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1.
Lancet ; 390(10104): 1758-1768, 2017 Oct 14.
Artículo en Inglés | MEDLINE | ID: mdl-28803710

RESUMEN

BACKGROUND: Niemann-Pick disease, type C1 (NPC1) is a lysosomal storage disorder characterised by progressive neurodegeneration. In preclinical testing, 2-hydroxypropyl-ß-cyclodextrins (HPßCD) significantly delayed cerebellar Purkinje cell loss, slowed progression of neurological manifestations, and increased lifespan in mouse and cat models of NPC1. The aim of this study was to assess the safety and efficacy of lumbar intrathecal HPßCD. METHODS: In this open-label, dose-escalation phase 1-2a study, we gave monthly intrathecal HPßCD to participants with NPC1 with neurological manifestation at the National Institutes of Health (NIH), Bethesda, MD, USA. To explore the potential effect of 2-week dosing, three additional participants were enrolled in a parallel study at Rush University Medical Center (RUMC), Chicago, IL, USA. Participants from the NIH were non-randomly, sequentially assigned in cohorts of three to receive monthly initial intrathecal HPßCD at doses of 50, 200, 300, or 400 mg per month. A fifth cohort of two participants received initial doses of 900 mg. Participants from RUMC initially received 200 or 400 mg every 2 weeks. The dose was escalated based on tolerance or safety data from higher dose cohorts. Serum and CSF 24(S)-hydroxycholesterol (24[S]-HC), which serves as a biomarker of target engagement, and CSF protein biomarkers were evaluated. NPC Neurological Severity Scores (NNSS) were used to compare disease progression in HPßCD-treated participants relative to a historical comparison cohort of 21 NPC1 participants of similar age range. FINDINGS: Between Sept 21, 2013, and Jan 19, 2015, 32 participants with NPC1 were assessed for eligibility at the National Institutes of Health. 18 patients were excluded due to inclusion criteria not met (six patients), declined to participate (three patients), pursued independent expanded access and obtained the drug outside of the study (three patients), enrolled in the RUMC cohort (one patient), or too late for the trial enrolment (five patients). 14 patients were enrolled and sequentially assigned to receive intrathecal HPßCD at a starting dose of 50 mg per month (three patients), 200 mg per month (three patients), 300 mg per month (three patients), 400 mg per month (three patients), or 900 mg per month (two patients). During the first year, two patients had treatment interrupted for one dose, based on grade 1 ototoxicity. All 14 patients were assessed at 12 months. Between 12 and 18 months, one participant had treatment interrupted at 17 months due to hepatocellular carcinoma, one patient had dose interruption for 2 doses based on caregiver hardship and one patient had treatment interrupted for 1 dose for mastoiditis. 11 patients were assessed at 18 months. Between Dec 11, 2013, and June 25, 2014, three participants were assessed for eligibility and enrolled at RUMC, and were assigned to receive intrathecal HPßCD at a starting dose of 200 mg every 2 weeks (two patients), or 400 mg every two weeks (one patient). There were no dropouts in this group and all 3 patients were assessed at 18 months. Biomarker studies were consistent with improved neuronal cholesterol homoeostasis and decreased neuronal pathology. Post-drug plasma 24(S)-HC area under the curve (AUC8-72) values, an indicator of neuronal cholesterol homoeostasis, were significantly higher than post-saline plasma 24(S)-HC AUC8-72 after doses of 900 mg (p=0·0063) and 1200 mg (p=0·0037). CSF 24(S)-HC concentrations in three participants given either 600 or 900 mg of HPßCD were increased about two fold (p=0·0032) after drug administration. No drug-related serious adverse events were observed. Mid-frequency to high-frequency hearing loss, an expected adverse event, was documented in all participants. When managed with hearing aids, this did not have an appreciable effect on daily communication. The NNSS for the 14 participants treated monthly increased at a rate of 1·22, SEM 0·34 points per year compared with 2·92, SEM 0·27 points per year (p=0·0002) for the 21 patient comparison group. Decreased progression was observed for NNSS domains of ambulation (p=0·0622), cognition (p=0·0040) and speech (p=0·0423). INTERPRETATION: Patients with NPC1 treated with intrathecal HPßCD had slowed disease progression with an acceptable safety profile. These data support the initiation of a multinational, randomised, controlled trial of intrathecal HPßCD. FUNDING: National Institutes of Health, Dana's Angels Research Trust, Ara Parseghian Medical Research Foundation, Hope for Haley, Samantha's Search for the Cure Foundation, National Niemann-Pick Disease Foundation, Support of Accelerated Research for NPC Disease, Vtesse, Janssen Research and Development, a Johnson & Johnson company, and Johnson & Johnson.


Asunto(s)
2-Hidroxipropil-beta-Ciclodextrina/administración & dosificación , Progresión de la Enfermedad , Enfermedad de Niemann-Pick Tipo C/tratamiento farmacológico , 2-Hidroxipropil-beta-Ciclodextrina/efectos adversos , Adolescente , Biomarcadores/sangre , Biomarcadores/líquido cefalorraquídeo , Calbindinas/líquido cefalorraquídeo , Niño , Preescolar , Relación Dosis-Respuesta a Droga , Proteína 3 de Unión a Ácidos Grasos/líquido cefalorraquídeo , Femenino , Pérdida Auditiva de Alta Frecuencia/inducido químicamente , Humanos , Hidroxicolesteroles/sangre , Hidroxicolesteroles/líquido cefalorraquídeo , Inyecciones Espinales , Masculino , Enfermedad de Niemann-Pick Tipo C/sangre , Enfermedad de Niemann-Pick Tipo C/líquido cefalorraquídeo , Enfermedades Raras/tratamiento farmacológico , Adulto Joven
2.
Stat Med ; 36(1): 81-91, 2017 01 15.
Artículo en Inglés | MEDLINE | ID: mdl-27538729

RESUMEN

The linear mixed effects model based on a full likelihood is one of the few methods available to model longitudinal data subject to left censoring. However, a full likelihood approach is complicated algebraically because of the large dimension of the numeric computations, and maximum likelihood estimation can be computationally prohibitive when the data are heavily censored. Moreover, for mixed models, the complexity of the computation increases as the dimension of the random effects in the model increases. We propose a method based on pseudo likelihood that simplifies the computational complexities, allows a wide class of multivariate models, and that can be used for many different data structures including settings where the level of censoring is high. The motivation for this work comes from the need for a joint model to assess the joint effect of pro-inflammatory and anti-inflammatory biomarker data on 30-day mortality status while simultaneously accounting for longitudinal left censoring and correlation between markers in the analysis of Genetic and Inflammatory Markers for Sepsis study conducted at the University of Pittsburgh. Two markers, interleukin-6 and interleukin-10, which naturally are correlated because of a shared similar biological pathways and are left-censored because of the limited sensitivity of the assays, are considered to determine if higher levels of these markers is associated with an increased risk of death after accounting for the left censoring and their assumed correlation. Copyright © 2016 John Wiley & Sons, Ltd.


Asunto(s)
Biomarcadores/sangre , Interleucina-10/sangre , Interleucina-6/sangre , Funciones de Verosimilitud , Sepsis/sangre , Sepsis/mortalidad , Simulación por Computador , Humanos , Modelos Estadísticos
3.
Lancet Neurol ; 14(8): 804-813, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26139022

RESUMEN

BACKGROUND: The biomarker model of Alzheimer's disease postulates a dynamic sequence of amyloidosis, neurodegeneration, and cognitive decline as an individual progresses from preclinical Alzheimer's disease to dementia. Despite supportive evidence from cross-sectional studies, verification with long-term within-individual data is needed. METHODS: For this prospective cohort study, carriers of autosomal dominant Alzheimer's disease mutations (aged ≥21 years) were recruited from across the USA through referrals by physicians or from affected families. People with mutations in PSEN1, PSEN2, or APP were assessed at the University of Pittsburgh Alzheimer's Disease Research Center every 1-2 years, between March 23, 2003, and Aug 1, 2014. We measured global cerebral amyloid ß (Aß) load using (11)C-Pittsburgh Compound-B PET, posterior cortical metabolism with (18)F-fluorodeoxyglucose PET, hippocampal volume (age and sex corrected) with T1-weighted MRI, verbal memory with the ten-item Consortium to Establish a Registry for Alzheimer's Disease Word List Learning Delayed Recall Test, and general cognition with the Mini Mental State Examination. We estimated overall biomarker trajectories across estimated years from symptom onset using linear mixed models, and compared these estimates with cross-sectional data from cognitively normal control individuals (age 65-89 years) who were negative for amyloidosis, hypometabolism, and hippocampal atrophy. In the mutation carriers who had the longest follow-up, we examined the within-individual progression of amyloidosis, metabolism, hippocampal volume, and cognition to identify progressive within-individual changes (a significant change was defined as an increase or decrease of more than two Z scores standardised to controls). FINDINGS: 16 people with mutations in PSEN1, PSEN2, or APP, aged 28-56 years, completed between two and eight assessments (a total of 83 assessments) over 2-11 years. Significant differences in mutation carriers compared with controls (p<0·01) were detected in the following order: increased amyloidosis (7·5 years before expected onset), decreased metabolism (at time of expected onset), decreased hippocampal volume and verbal memory (7·5 years after expected onset), and decreased general cognition (10 years after expected onset). Among the seven participants with longest follow-up (seven or eight assessments spanning 6-11 years), three individuals had active amyloidosis without progressive neurodegeneration or cognitive decline, two amyloid-positive individuals showed progressive neurodegeneration and cognitive decline without further progressive amyloidosis, and two amyloid-positive individuals showed neither active amyloidosis nor progressive neurodegeneration or cognitive decline. INTERPRETATION: Our results support amyloidosis as the earliest component of the biomarker model in autosomal dominant Alzheimer's disease. Our within-individual examination suggests three sequential phases in the development of autosomal dominant Alzheimer's disease-active amyloidosis, a stable amyloid-positive period, and progressive neurodegeneration and cognitive decline-indicating that Aß accumulation is largely complete before progressive neurodegeneration and cognitive decline occur. These findings offer supportive evidence for efforts to target early Aß deposition for secondary prevention in individuals with autosomal dominant Alzheimer's disease. FUNDING: National Institutes of Health and Howard Hughes Medical Institute.


Asunto(s)
Enfermedad de Alzheimer , Péptidos beta-Amiloides/metabolismo , Amiloidosis/metabolismo , Biomarcadores , Corteza Cerebral , Progresión de la Enfermedad , Adulto , Anciano , Anciano de 80 o más Años , Enfermedad de Alzheimer/genética , Enfermedad de Alzheimer/metabolismo , Enfermedad de Alzheimer/patología , Enfermedad de Alzheimer/fisiopatología , Compuestos de Anilina , Corteza Cerebral/metabolismo , Corteza Cerebral/patología , Corteza Cerebral/fisiopatología , Femenino , Hipocampo/patología , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Tiazoles
4.
Crit Care Med ; 42(5): 1037-46, 2014 May.
Artículo en Inglés | MEDLINE | ID: mdl-24368344

RESUMEN

OBJECTIVES: Severe infections, often requiring ICU admission, have been associated with persistent cognitive dysfunction. Less severe infections are more common and whether they are associated with an increased risk of dementia is unclear. We determined the association of pneumonia hospitalization with risk of dementia in well-functioning older adults. DESIGN: Secondary analysis of a randomized multicenter trial to determine the effect of Gingko biloba on incident dementia. SETTING: Five academic medical centers in the United States. SUBJECTS: Healthy community volunteers (n = 3,069) with a median follow-up of 6.1 years. INTERVENTIONS: None. MEASUREMENT AND MAIN RESULTS: We identified pneumonia hospitalizations using International Classification of Diseases, 9th Edition-Coding Manual codes and validated them in a subset. Less than 3% of pneumonia cases necessitated ICU admission, mechanical ventilation, or vasopressor support. Dementia was adjudicated based on neuropsychological evaluation, neurological examination, and MRI. Two hundred twenty-one participants (7.2%) incurred at least one hospitalization with pneumonia (mean time to pneumonia = 3.5 yr). Of these, dementia was developed in 38 (17%) after pneumonia, with half of these cases occurring 2 years after the pneumonia hospitalization. Hospitalization with pneumonia was associated with increased risk of time to dementia diagnosis (unadjusted hazard ratio = 2.3; CI, 1.6-3.2; p < 0.0001). The association remained significant when adjusted for age, sex, race, study site, education, and baseline mini-mental status examination (hazard ratio = 1.9; CI, 1.4-2.8; p < 0.0001). Results were unchanged when additionally adjusted for smoking, hypertension, diabetes, heart disease, and preinfection functional status. Results were similar using propensity analysis where participants with pneumonia were matched to those without pneumonia based on age, probability of developing pneumonia, and similar trajectories of cognitive and physical function prior to pneumonia (adjusted prevalence rates, 91.7 vs 65 cases per 1,000 person-years; adjusted prevalence rate ratio = 1.6; CI, 1.06-2.7; p = 0.03). Sensitivity analyses showed that the higher risk also occurred among those hospitalized with other infections. CONCLUSION: Hospitalization with pneumonia is associated with increased risk of dementia.


Asunto(s)
Demencia/etiología , Hospitalización , Neumonía/complicaciones , Anciano , Anciano de 80 o más Años , Demencia/diagnóstico , Demencia/epidemiología , Femenino , Humanos , Masculino , Prevalencia , Puntaje de Propensión , Escalas de Valoración Psiquiátrica , Riesgo , Factores de Riesgo , Estados Unidos/epidemiología
5.
Chest ; 144(3): 1008-1017, 2013 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-23744106

RESUMEN

BACKGROUND: Preventing pneumonia requires better understanding of incidence, mortality, and long-term clinical and biologic risk factors, particularly in younger individuals. METHODS: This was a cohort study in three population-based cohorts of community-dwelling individuals. A derivation cohort (n = 16,260) was used to determine incidence and survival and develop a risk prediction model. The prediction model was validated in two cohorts (n = 8,495). The primary outcome was 10-year risk of pneumonia hospitalization. RESULTS: The crude and age-adjusted incidences of pneumonia were 6.71 and 9.43 cases/1,000 person-years (10-year risk was 6.15%). The 30-day and 1-year mortality were 16.5% and 31.5%. Although age was the most important risk factor (range of crude incidence rates, 1.69-39.13 cases/1,000 person-years for each 5-year increment from 45-85 years), 38% of pneumonia cases occurred in adults < 65 years of age. The 30-day and 1-year mortality were 12.5% and 25.7% in those < 65 years of age. Although most comorbidities were associated with higher risk of pneumonia, reduced lung function was the most important risk factor (relative risk = 6.61 for severe reduction based on FEV1 by spirometry). A clinical risk prediction model based on age, smoking, and lung function predicted 10-year risk (area under curve [AUC] = 0.77 and Hosmer-Lemeshow [HL] C statistic = 0.12). Model discrimination and calibration were similar in the internal validation cohort (AUC = 0.77; HL C statistic, 0.65) but lower in the external validation cohort (AUC = 0.62; HL C statistic, 0.45). The model also calibrated well in blacks and younger adults. C-reactive protein and IL-6 were associated with higher pneumonia risk but did not improve model performance. CONCLUSIONS: Pneumonia hospitalization is common and associated with high mortality, even in younger healthy adults. Long-term risk of pneumonia can be predicted in community-dwelling adults with a simple clinical risk prediction model.


Asunto(s)
Infecciones Comunitarias Adquiridas/epidemiología , Neumonía/epidemiología , Medición de Riesgo , Factores de Edad , Anciano , Anciano de 80 o más Años , Comorbilidad , Femenino , Estudios de Seguimiento , Hospitalización/estadística & datos numéricos , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Pronóstico , Estudios Prospectivos , Factores de Riesgo , Tasa de Supervivencia/tendencias , Factores de Tiempo
6.
Neuroimage ; 71: 207-15, 2013 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-23353602

RESUMEN

UNLABELLED: An important research application of amyloid imaging with positron emission tomography (PET) is detection of the earliest evidence of fibrillar amyloid-beta (Aß) deposition. Use of amyloid PET for this purpose, requires a reproducible method for defining a cutoff that separates individuals with no significant Aß deposition from those in which Aß deposition has begun. We previously reported the iterative outlier approach (IO) for the analysis of Pittsburgh Compound-B (PiB) PET data. Developments in amyloid imaging since the initial report of IO have led us to re-examine the generalizability of this method. IO was developed using full-dynamic atrophy-corrected PiB PET data obtained from a group of control subjects with a fairly distinct separation between PiB-positive [PiB(+)] and PiB-negative [PiB(-)] subjects. METHODS: We tested the performance of IO using late-summed tissue ratio data with atrophy correction or with an automated template method without atrophy correction and tested the robustness of the method when applied to a cohort of older subjects in which separation between PiB(+) and PiB(-) subjects was not so distinct. RESULTS: The IO method did not perform consistently across analyses and performed particularly poorly when separation was less clear. We found that a sparse k-means (SKM) cluster analysis approach performed significantly better; performing more consistently across methods and subject cohorts. We also compared SKM to a consensus visual read approach and found very good correspondence. CONCLUSION: The visual read and SKM methods, applied together, may optimize the identification of early Aß deposition. These methods have the potential to provide a standard approach to the detection of PiB-positivity that is generalizable across centers.


Asunto(s)
Amiloide/análisis , Amiloidosis/diagnóstico por imagen , Compuestos de Anilina , Encéfalo/diagnóstico por imagen , Tomografía de Emisión de Positrones/métodos , Radiofármacos , Tiazoles , Adulto , Anciano , Encéfalo/patología , Análisis por Conglomerados , Humanos , Persona de Mediana Edad
7.
Stat Med ; 31(17): 1838-48, 2012 Jul 30.
Artículo en Inglés | MEDLINE | ID: mdl-22359320

RESUMEN

Biomarkers, increasingly used in biomedical studies for the diagnosis and prognosis of acute and chronic diseases, provide insight into the effectiveness of treatments and potential pathways that can be used to guide future treatment targets. The measurement of these markers is often limited by the sensitivity of the given assay, resulting in data that are censored either at the lower or at the upper limit of detection. For the Genetic and Inflammatory Markers of Sepsis (GenIMS) study, many different biomarkers were measured to examine the effect of different pathways on the development of sepsis. In this study, the left-censoring of several important inflammatory markers has led to the need for statistical methods that can incorporate this censoring into any analysis of the biomarker data. This paper focuses on the development of multiple imputation methods for the inclusion of multiple left-censored biomarkers in a logistic regression analysis. We assume a multivariate normal distribution to account for the correlations between biomarkers and use the Gibbs sampler for the estimation of the distributional parameters and the imputation of the censored markers. We evaluate and compare the proposed methods with some simple imputation methods through simulation. We use a data set of inflammatory and coagulation markers from the GenIMS study for illustration.


Asunto(s)
Interpretación Estadística de Datos , Biomarcadores/análisis , Biomarcadores/sangre , Simulación por Computador , Humanos , Interleucina-10/sangre , Interleucina-6/sangre , Análisis de Regresión , Sepsis/sangre , Sepsis/diagnóstico , Sepsis/inmunología , Factor de Necrosis Tumoral alfa/sangre
8.
Cancer Epidemiol Biomarkers Prev ; 20(11): 2429-37, 2011 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-21890746

RESUMEN

BACKGROUND: Germline variation in DNA damage response may explain variable treatment outcomes in squamous cell carcinoma of the head and neck (SCCHN). By grouping patients according to stage and radiation treatment, we compared SCCHN survival with regard to ERCC2 A35931C (Lys751Gln, rs13181) and CCND1 G870A (Pro241Pro, rs9344) genotypes. METHODS: In a hospital-based SCCHN case series (all white, 24.7% female, mean age 58.4 years), this treatment-outcome cohort study genotyped 275 stage III-IV cases that were initially treated with radiation (with or without chemotherapy) and 80 stage III-IV and 130 stage I-II cases that were initially treated without radiation or chemotherapy and used Kaplan-Meier and Cox regression analyses to compare genotype groups on the basis of overall, disease-specific, progression-free, and recurrence-free survival rates. RESULTS: ERCC2 35931 AA predicted worse survival in stage III-IV cases treated with radiation [multiply-adjusted HR = 1.66, 95% confidence interval (CI), 1.15-2.40; HR over the first 3 follow-up years = 1.92; 95% CI, 1.28-2.88] and better survival in stage III-IV cases not treated with radiation (HR = 0.26; 95% CI, 0.11-0.62). Although not associated with survival in stage III-IV cancers treated with radiation (HR = 1.00; 95% CI, 0.67-1.51), CCND1-870 GG predicted better survival in stage III-IV cancers not treated with radiation (HR = 0.14; 95% CI, 0.04-0.50). Survival in stage I-II did not depend on ERCC2 A35931C or CCND1 G870A genotype. CONCLUSIONS: Although promoting tumor progression in untreated patients, germline differences in DNA-repair or cell-cycle control may improve treatment outcome in patients treated with DNA-damaging agents. IMPACT: ERCC2 A35931C may help distinguish advanced stage SCCHN with better outcomes from radiation treatment.


Asunto(s)
Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/radioterapia , Ciclina D1/genética , Neoplasias de Cabeza y Cuello/genética , Neoplasias de Cabeza y Cuello/radioterapia , Proteína de la Xerodermia Pigmentosa del Grupo D/genética , Adulto , Anciano , Carcinoma de Células Escamosas/tratamiento farmacológico , Carcinoma de Células Escamosas/patología , Estudios de Cohortes , Terapia Combinada , Daño del ADN , Reparación del ADN , Femenino , Predisposición Genética a la Enfermedad , Genotipo , Neoplasias de Cabeza y Cuello/tratamiento farmacológico , Neoplasias de Cabeza y Cuello/patología , Humanos , Masculino , Persona de Mediana Edad , Estadificación de Neoplasias , Polimorfismo de Nucleótido Simple , Carcinoma de Células Escamosas de Cabeza y Cuello , Análisis de Supervivencia , Resultado del Tratamiento
9.
Stat Med ; 30(27): 3167-80, 2011 Nov 30.
Artículo en Inglés | MEDLINE | ID: mdl-21898524

RESUMEN

In a longitudinal study with response data collected during a hospital stay, observations may be missing because of the subject's discharge from the hospital prior to completion of the study or the death of the subject, resulting in non-ignorable missing data. In addition to non-ignorable missingness, there is left-censoring in the response measurements because of the inherent limit of detection. For analyzing non-ignorable missing and left-censored longitudinal data, we have proposed to extend the theory of random effects tobit regression model to weighted random effects tobit regression model. The weights are computed on the basis of inverse probability weighted augmented methodology. An extensive simulation study was performed to compare the performance of the proposed model with a number of competitive models. The simulation study shows that the estimates are consistent and that the root mean square errors of the estimates are minimal for the use of augmented inverse probability weights in the random effects tobit model. The proposed method is also applied to the non-ignorable missing and left-censored interleukin-6 biomarker data obtained from the Genetic and Inflammatory Markers of Sepsis study.


Asunto(s)
Interpretación Estadística de Datos , Estudios Longitudinales , Modelos Estadísticos , Biomarcadores/sangre , Simulación por Computador , Humanos , Interleucina-6/sangre , Sepsis/sangre , Sepsis/genética , Sepsis/inmunología
10.
Crit Care Med ; 39(8): 1871-8, 2011 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-21516038

RESUMEN

OBJECTIVE: To examine the association of statin use with clinical outcomes and circulating biomarkers in community-acquired pneumonia and sepsis. DESIGN: Multicenter inception cohort study. SETTING: Emergency departments of 28 U.S. hospitals. PATIENTS: A total of 1895 subjects hospitalized with community-acquired pneumonia. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Our approach consisted of two different comparison cohorts, each reflecting methods used in prior publications in this area. We first compared subjects with prior statin use (prior use cohort), defined as a history of statin use in the week before admission, with those with no prior use. We then compared prior statin users whose statins were continued inhospital (continued use cohort) with those with either no prior use or no inhospital use. We adjusted for patient characteristics, including demographics, comorbid conditions, and illness severity, and accounted for healthy user effect and indication bias using propensity analysis. We determined risk of severe sepsis and 90-day mortality. We measured markers inflammation (tumor necrosis factor, interleukin-6, interleukin-10), coagulation (antithrombin, factor IX, plasminogen activator inhibitor, d-dimer, thrombin antithrombin complex), and lymphocyte cell surface protein expression during the first week of hospitalization. There were no differences in severe sepsis risk between statin users and nonusers for prior (30.8% vs. 30.7%, p = .98) or continued statin use (30.2% vs. 30.8%, p = .85) in univariate analyses and after adjusting for patient characteristics and propensity for statin use. Ninety-day mortality was similar in prior statin users (9.2% vs. 12.0%, p = .11) and lower in continued statin users (7.9% vs. 12.1%, p = .02). After adjusting for patient characteristics and propensity for statin use, there was no mortality benefit for prior (odds ratio, 0.90 [0.63-1.29]; p = .57) or continued statin use (odds ratio, 0.73 [0.47-1.13]; p = .15). Only antithrombin activity over time was higher in statin subjects, yet the magnitude of the difference was modest. There were no differences in other coagulation, inflammatory, or lymphocyte cell surface markers. CONCLUSIONS: We found no evidence of a protective effect for statin use on clinical outcomes and only modest differences in circulating biomarkers in community-acquired pneumonia, perhaps as a result of healthy user effects and indication bias.


Asunto(s)
Mortalidad Hospitalaria/tendencias , Inhibidores de Hidroximetilglutaril-CoA Reductasas/administración & dosificación , Neumonía Bacteriana/tratamiento farmacológico , Neumonía Bacteriana/mortalidad , Sepsis/tratamiento farmacológico , Sepsis/mortalidad , Adulto , Anciano , Estudios de Cohortes , Infecciones Comunitarias Adquiridas/tratamiento farmacológico , Infecciones Comunitarias Adquiridas/mortalidad , Infecciones Comunitarias Adquiridas/prevención & control , Intervalos de Confianza , Cuidados Críticos/métodos , Enfermedad Crítica , Relación Dosis-Respuesta a Droga , Esquema de Medicación , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Neumonía Bacteriana/prevención & control , Estudios Prospectivos , Medición de Riesgo , Rol , Sepsis/prevención & control , Tasa de Supervivencia , Resultado del Tratamiento
11.
Crit Care Med ; 37(5): 1655-62, 2009 May.
Artículo en Inglés | MEDLINE | ID: mdl-19325487

RESUMEN

OBJECTIVE: Lower life expectancy in men is generally attributed to higher likelihood of risky behavior and because men develop chronic conditions earlier. If sex-related differences in survival are independent of preinfection chronic health and health behavior, it would suggest that survival differences may occur because of sex differences in quality of care and biological response to infection, and these differences may contribute to sex differences in life expectancy. We assessed if sex-related survival difference following community-acquired pneumonia (CAP) is due to differences in clinical characteristics, quality of care, or immune response. DESIGN, SETTING, AND SUBJECTS: Prospective observational cohort of 2183 subjects with CAP. MEASUREMENTS AND MAIN RESULTS: Mean age was 64.9 years. Men were more likely to smoke and had more comorbidity compared with women. At emergency department presentation, men had different biomarker patterns, as evidenced by higher inflammation (tumor necrosis factor, interleukin [IL]-6, and IL-10) and fibrinolysis (d-dimer), and lower coagulation biomarkers (antithrombin-III and factor IX) (p < 0.05). Small differences in favor of men were seen in care quality, including antibiotic timing and compliance with American Thoracic Society guidelines. Men had lower survival at 30, 90, and 365 days. The higher 1-year mortality was not attenuated when adjusted for differences in demographics, smoking, resuscitation, insurance, and vaccination status, comorbidity, hospital characteristics, and illness severity (unadjusted hazard ratio [HR] = 1.35, p = 0.003; and adjusted HR = 1.29, p = 0.004). HR was no longer statistically significant when additionally adjusted for differences in emergency department concentrations of tumor necrosis factor, IL-6, IL-10, d-dimer, antithrombin-III, and factor IX (adjusted HR = 1.27, p = 0.17). Patterns of biomarkers observed in men were associated with worse survival for 1 year. CONCLUSIONS: Lower survival among men following CAP was not explained by differences in chronic diseases, health behaviors, and quality of care. Patterns of inflammatory, coagulation, and fibrinolysis biomarkers among men may explain reduced short-term and long-term survival.


Asunto(s)
Causas de Muerte , Enfermedad Crítica/mortalidad , Mortalidad Hospitalaria/tendencias , Fenómenos del Sistema Inmunológico/fisiología , Neumonía/inmunología , Neumonía/mortalidad , Sepsis/inmunología , Sepsis/mortalidad , Factores de Edad , Anciano , Anciano de 80 o más Años , Actitud Frente a la Salud , Estudios de Cohortes , Servicio de Urgencia en Hospital , Femenino , Humanos , Modelos Lineales , Modelos Logísticos , Masculino , Persona de Mediana Edad , Análisis Multivariante , Neumonía/diagnóstico , Probabilidad , Estudios Prospectivos , Factores de Riesgo , Sepsis/diagnóstico , Factores Sexuales , Análisis de Supervivencia
12.
Commun Stat Theory Methods ; 38(15): 2604-2619, 2009 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-20523912

RESUMEN

Non ignorable missing data is a common problem in longitudinal studies. Latent class models are attractive for simplifying the modeling of missing data when the data are subject to either a monotone or intermittent missing data pattern. In our study, we propose a new two-latent-class model for categorical data with informative dropouts, dividing the observed data into two latent classes; one class in which the outcomes are deterministic and a second one in which the outcomes can be modeled using logistic regression. In the model, the latent classes connect the longitudinal responses and the missingness process under the assumption of conditional independence. Parameters are estimated by the method of maximum likelihood estimation based on the above assumptions and the tetrachoric correlation between responses within the same subject. We compare the proposed method with the shared parameter model and the weighted GEE model using the areas under the ROC curves in the simulations and the application to the smoking cessation data set. The simulation results indicate that the proposed two-latent-class model performs well under different missing procedures. The application results show that our proposed method is better than the shared parameter model and the weighted GEE model.

13.
Pediatrics ; 122(1): e172-80, 2008 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-18595962

RESUMEN

OBJECTIVES: Traumatic brain injury is a leading cause of death in children. On the basis of evidence of better outcomes, the American College of Surgery Committee on Trauma recommends that children with severe traumatic brain injury receive care at high-level trauma centers. We assessed rates of adherence to these recommendations and factors associated with adherence. METHODS: We studied population and hospital discharge data from 2001 from all of the health care referral regions (n = 68) in 6 US states (Florida, Massachusetts, New Jersey, New York, Texas, and Virginia). We identified children with severe traumatic brain injury by using International Classification of Diseases, Ninth Revision, Clinical Modification, codes and American College of Surgery Committee on Trauma criteria. We defined "high-level centers" as either level I or pediatric trauma centers. We considered an area to be well regionalized if >or=90% of severe traumatic brain injury hospitalizations were in high-level centers. We also explored how use of level II trauma centers affected rates of care at high-level centers. RESULTS: Of 2117 admissions for severe pediatric traumatic brain injury, 67.3% were in high-level centers, and 87.3% were in either high-level or level II centers. Among states, 56.4% to 93.6% of severe traumatic brain injury admissions were in high-level centers. Only 2 states, Massachusetts and Virginia, were well regionalized. Across health care referral regions, 0% to 100% of severe traumatic brain injury admissions were in high-level centers, and only 19.1% of health care referral regions were well regionalized. Only a weak relationship existed between the distance to the nearest high-level center and regionalization. The age of statewide trauma systems had no relationship to the extent of regionalization. CONCLUSIONS: Despite evidence for improved outcomes of severely injured children admitted to high-level trauma centers, we found that almost one third of the children with severe traumatic brain injury failed to receive care in such centers. Only 2 of 6 states and less than one fifth of 68 health care referral regions were well regionalized. This study highlights problems with current pediatric trauma care that can serve as a basis for additional research and health care policy.


Asunto(s)
Lesiones Encefálicas/terapia , Adhesión a Directriz , Admisión del Paciente/estadística & datos numéricos , Centros Traumatológicos/organización & administración , Adolescente , Áreas de Influencia de Salud , Niño , Preescolar , Femenino , Humanos , Lactante , Puntaje de Gravedad del Traumatismo , Masculino , Admisión del Paciente/normas , Guías de Práctica Clínica como Asunto , Evaluación de Procesos, Atención de Salud , Centros Traumatológicos/estadística & datos numéricos , Estados Unidos
14.
Am J Respir Crit Care Med ; 177(11): 1242-7, 2008 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-18369199

RESUMEN

RATIONALE: Survivors of hospitalization for community-acquired pneumonia (CAP) are at increased risk of cardiovascular events, repeat infections, and death in the following months but the cause is unknown. OBJECTIVES: To investigate whether persistent inflammation, defined as elevating circulating inflammatory markers at hospital discharge, is associated with subsequent outcomes. METHODS: Prospective cohort study at 28 sites. MEASUREMENTS AND MAIN RESULTS: We used standard criteria to define CAP and the National Death Index to determine all-cause and cause-specific 1-year mortality. At hospital discharge, 1,799 subjects (77.5%) were alive and vital signs had returned to normal in 1,512 (87%) subjects. The geometric means (+/-SD) for circulating IL-6 and IL-10 concentrations were 6.9 (+/-1) pg/ml and 1.2 (+/-1.1) pg/ml. At 1 year, 307 (17.1%) subjects had died. Higher IL-6 and IL-10 concentrations at hospital discharge were associated with an increased risk of death, which gradually fell over time. Using Gray's survival model, the associations were independent of demographics, comorbidities, and severity of illness (for each log-unit increase, the range of adjusted hazard ratios [HRs] for IL-6 were 1.02-1.46, P < 0.0001, and for IL-10 were 1.17-1.44, P = 0.01). The ranges of HRs for each log-unit increase in IL-6 and IL-10 concentrations among subjects who did and did not develop severe sepsis were 0.95-1.27 and 1.07-1.55, respectively. High IL-6 concentrations were associated with death due to cardiovascular disease, cancer, infections, and renal failure (P = 0.008). CONCLUSIONS: Despite clinical recovery, many patients with CAP leave hospital with ongoing subclinical inflammation, which is associated with an increased risk of death.


Asunto(s)
Interleucina-10/sangre , Interleucina-6/sangre , Neumonía/sangre , Neumonía/mortalidad , Sepsis/sangre , Sepsis/mortalidad , Anciano , Anciano de 80 o más Años , Estudios de Cohortes , Infecciones Comunitarias Adquiridas/sangre , Infecciones Comunitarias Adquiridas/mortalidad , Infecciones Comunitarias Adquiridas/terapia , Femenino , Humanos , Masculino , Persona de Mediana Edad , Alta del Paciente , Neumonía/terapia , Valor Predictivo de las Pruebas , Recuperación de la Función/fisiología , Sepsis/terapia , Tasa de Supervivencia , Resultado del Tratamiento
15.
Arch Intern Med ; 167(15): 1655-63, 2007.
Artículo en Inglés | MEDLINE | ID: mdl-17698689

RESUMEN

BACKGROUND: Severe sepsis is common and frequently fatal, and community-acquired pneumonia (CAP) is the leading cause. Although severe sepsis is often attributed to uncontrolled and unbalanced inflammation, evidence from humans with infection syndromes across the breadth of disease is lacking. In this study we describe the systemic cytokine response to pneumonia and determine if specific patterns, including the balance of proinflammatory and anti-inflammatory markers, are associated with severe sepsis and death. METHODS: This is a cohort study of 1886 subjects hospitalized with CAP through the emergency departments in 28 US academic and community hospitals. We defined severe sepsis as CAP complicated by new-onset organ dysfunction, following international consensus conference criteria. We measured plasma tumor necrosis factor, IL-6 (interleukin 6), and IL-10 levels daily for the first week and weekly thereafter. Our main outcome measures were severe sepsis and 90-day mortality. RESULTS: A total of 583 patients developed severe sepsis (31%), of whom 149 died (26%). Systemic cytokine level elevation occurred in 82% of all subjects with CAP. Mean cytokine concentrations were highest at presentation, declined rapidly over the first few days, but remained elevated throughout the first week, beyond resolution of clinical signs of infection. Cytokine levels were highest in fatal severe sepsis and lowest in CAP with no severe sepsis. Unbalanced (high/low) cytokine patterns were unusual (4.6%) and not associated with decreased survival. Highest risk of death was with combined high levels of the proinflammatory IL-6 and anti-inflammatory IL-10 cytokine activity (hazard ratio, 20.5; 95% confidence interval, 10.8-39.0) (P<.001). CONCLUSIONS: The circulating cytokine response to pneumonia is heterogeneous and continues for more than a week after presentation, with considerable overlap between those who do and do not develop severe sepsis. Unbalanced activation is uncommon, and mortality is highest when both proinflammatory and anti-inflammatory cytokine levels are high.


Asunto(s)
Interleucina-10/sangre , Interleucina-6/sangre , Neumonía Bacteriana/sangre , Neumonía Bacteriana/inmunología , Sepsis/sangre , Sepsis/inmunología , Factor de Necrosis Tumoral alfa/sangre , Anciano , Estudios de Cohortes , Infecciones Comunitarias Adquiridas/sangre , Infecciones Comunitarias Adquiridas/inmunología , Femenino , Humanos , Inflamación/complicaciones , Masculino , Índice de Severidad de la Enfermedad
16.
Am J Psychiatry ; 164(2): 328-34; quiz 374, 2007 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-17267797

RESUMEN

OBJECTIVE: The present study was designed to document psychiatric disorders among candidates for weight loss surgery and to examine the relationship of psychopathology to degree of obesity and functional health status. METHOD: The authors collected demographic and clinical information from 288 individuals seeking surgery. Assessments were administered independently of the preoperative screening and approval process. The study group was mostly female (83.3%) and white (88.2%). Mean body mass index (BMI) of the group was 52.2 kg/m(2) (SD=9.7), and the mean age was 46.2 years (SD=9.4). RESULTS: Approximately 66% of the participants had a lifetime history of at least one axis I disorder, and 38% met diagnostic criteria at the time of preoperative evaluation. In addition, 29% met criteria for one or more axis II disorders. Axis I psychopathology, but not axis II, was positively related to BMI, and both axis I and axis II psychopathology were associated with lower scores on the Medical Outcomes Study 36-item Short-Form Health Survey. CONCLUSIONS: Current and past DSM-IV psychiatric disorders are prevalent among bariatric surgery candidates and are associated with greater obesity and lower functional health status, highlighting the need to understand potential implications for surgery preparation and outcome. Future work also will focus on the course of psychiatric disorder during the post-surgery period and its relationship to weight loss and maintenance.


Asunto(s)
Cirugía Bariátrica , Estado de Salud , Trastornos Mentales/epidemiología , Obesidad/epidemiología , Obesidad/cirugía , Índice de Masa Corporal , Comorbilidad , Manual Diagnóstico y Estadístico de los Trastornos Mentales , Femenino , Humanos , Masculino , Trastornos Mentales/diagnóstico , Persona de Mediana Edad , Obesidad/psicología , Selección de Paciente , Trastornos de la Personalidad/diagnóstico , Trastornos de la Personalidad/epidemiología , Cuidados Preoperatorios , Prevalencia , Pronóstico , Escalas de Valoración Psiquiátrica , Resultado del Tratamiento
17.
Stat Med ; 26(10): 2137-53, 2007 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-16981225

RESUMEN

This paper addresses the modelling of missing covariate data with the logistic regression model. The aim of this paper is to evaluate the properties of an efficient score for logistic regression in a two-phase design. Simulation studies show that the efficient score is more efficient than two other pseudo-likelihood methods when the correlation between the missing covariate and its surrogate is high or the sampling proportion is small. These methods are illustrated with data from the National Wilms Tumor Study Group. Results from the example confirm the simulation study findings with the exception that the pseudo-likelihood approach produces more reliable estimates than the weighted pseudo-likelihood approach.


Asunto(s)
Investigación Biomédica/estadística & datos numéricos , Interpretación Estadística de Datos , Modelos Logísticos , Humanos , Funciones de Verosimilitud , Neoplasias , Estados Unidos
18.
Ann Behav Med ; 32(2): 147-53, 2006 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-16972812

RESUMEN

BACKGROUND: Although many women quit smoking during pregnancy, most resume smoking postpartum. One factor that may be important in postpartum relapse is a pregnant woman's motivation to remain abstinent after delivery. PURPOSE: We assessed motivation for postpartum abstinence among pregnant women who had quit smoking and examined the relationship of weight concerns and mood to abstinence motivation. METHODS: Pregnant former smokers, recruited between February 2000 and November 2004, completed assessments of smoking, weight concerns, depressive symptoms, and perceived stress. RESULTS: Sixty-five percent were highly motivated to remain abstinent postpartum. Women who were and were not motivated were similar in age, race, and nicotine dependence. However, motivated women reported more stress, greater self-efficacy for weight management, less hunger, and less smoking for weight control than did less motivated women. After controlling for intention to breast-feed, nicotine dependence, years of smoking, partner smoking, and race, self-efficacy for weight control was related to motivation to maintain postpartum abstinence. CONCLUSIONS: These data suggest that weight concerns are associated with motivation for postpartum smoking abstinence, and interventions designed to prevent postpartum smoking relapse may need to target eating, weight, and shape concerns.


Asunto(s)
Actitud Frente a la Salud , Peso Corporal , Conductas Relacionadas con la Salud , Motivación , Periodo Posparto/psicología , Fumar/epidemiología , Fumar/psicología , Adulto , Femenino , Humanos , Embarazo , Cese del Hábito de Fumar/estadística & datos numéricos , Aumento de Peso
19.
Crit Care Med ; 34(10): 2547-53, 2006 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-16932230

RESUMEN

OBJECTIVE: One in five Americans dies following treatment in an intensive care unit (ICU), and evidence indicates the need to improve end-of-life care for ICU patients. We conducted this study to elicit the views and experiences of ICU directors regarding barriers to optimal end-of-life care and to identify the type, availability, and perceived benefit of specific strategies that may improve this care. DESIGN: Self-administered mail survey. SETTING: Six hundred intensive care units. PARTICIPANTS: A random, nationally representative sample of nursing and physician directors of 600 adult ICUs in the United States. INTERVENTIONS: Mail survey. MEASUREMENTS AND MAIN RESULTS: We asked participants about barriers to end-of-life care (1 = huge to 5 = not at all a barrier), perceived benefit of strategies to improve end-of-life care, and availability of these strategies. From 468 ICUs (78.0% of sample), 590 ICU directors participated (406 nurses [65.1% response] and 184 physicians [31.7% response]). Respondents had a mean of 16.6 yrs (sd 7.6 yrs) of ICU experience. Important barriers to better end-of-life care included patient/family factors, including unrealistic patient/family expectations 2.5 (1.0), inability of patients to participate in discussions 2.7 (0.9), and lack of advance directives 2.9 (1.0); clinician factors, which included insufficient physician training in communication 2.9 (1.1) and competing demands on physicians' time 3.0 (1.1); and institution/ICU factors, such as suboptimal space for family meetings 3.5 (1.2) and lack of a palliative care service 3.4 (1.2). More than 80% of respondents rated 14 of 14 strategies as likely to improve end-of-life care, including trainee role modeling by experienced clinicians, clinician training in communication and symptom management, regular meetings of senior clinicians with families, bereavement programs, and end-of-life care quality monitoring. However, few of these strategies were widely available. CONCLUSIONS: Intensive care unit directors perceive important barriers to optimal end-of-life care but also universally endorse many practical strategies for quality improvement.


Asunto(s)
Actitud del Personal de Salud , Unidades de Cuidados Intensivos/normas , Cuidados Paliativos/métodos , Calidad de la Atención de Salud , Cuidado Terminal/métodos , Femenino , Encuestas de Atención de la Salud , Humanos , Unidades de Cuidados Intensivos/estadística & datos numéricos , Masculino , Persona de Mediana Edad , Enfermeras Administradoras/psicología , Cuidados Paliativos/organización & administración , Ejecutivos Médicos/psicología , Garantía de la Calidad de Atención de Salud , Cuidado Terminal/organización & administración , Estados Unidos
20.
J Am Geriatr Soc ; 53(9): 1532-7, 2005 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-16137283

RESUMEN

OBJECTIVES: To study the levels of systemic markers for inflammation with parameters of periodontal diseases in older people. DESIGN: A cross-sectional study was conducted in a cohort that is being followed prospectively on the effects of aging and body composition on morbidity. SETTING: University of Pittsburgh, Pittsburgh, and University of Tennessee, Memphis. PARTICIPANTS: One thousand one hundred thirty-one participants (mean age+/-standard deviation 72.7+/-2.8); 66% white and 50% male. MEASUREMENTS: Periodontal examination, including probing depth and attachment loss, was performed. Periodontal disease extent was divided into 0% of sites with probing depth of 6 mm or more, 1% to 10% of sites with probing depth of 6 mm or more and more than 10% of sites with probing depth of 6 mm or more. Subgingival plaque samples were collected from four molar teeth, and the levels of periodontal pathogens were determined using the benzoyl-DL-arginine-naphthylamide (BANA) test. Plasma interleukin-6 (IL-6), C-reactive protein (CRP), plasminogen activator inhibitor type-1 (PAI-1), and tumor necrosis factor alpha (TNF-alpha) levels were measured in all participants. Assessments of risk factors associated with elevated levels of markers of systemic inflammation were also determined. Multiple regression analysis was employed to analyze the data. RESULTS: IL-6 levels were significantly higher in participants with more-extensive periodontal disease than in other participants. Periodontal disease extent was significantly associated with higher TNF-alpha plasma levels, controlling for established risk factors for elevated TNF-alpha levels. Participants with BANA-positive species had significantly higher CRP plasma levels when controlling for risk factors for elevated CRP levels. CONCLUSION: Periodontal disease and infection may be modifiable risk indicators for elevated levels of systemic inflammatory markers in older people.


Asunto(s)
Biomarcadores/sangre , Infecciones/etiología , Inflamación/sangre , Enfermedades Periodontales/etiología , Anciano , Benzoilarginina-2-Naftilamida , Proteína C-Reactiva/análisis , Estudios de Cohortes , Estudios Transversales , Femenino , Humanos , Interleucina-6/sangre , Masculino , Enfermedades Periodontales/sangre , Inhibidor 1 de Activador Plasminogénico/sangre , Estudios Prospectivos , Factor de Necrosis Tumoral alfa/análisis
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