Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 82
Filtrar
Más filtros

Tipo del documento
Intervalo de año de publicación
1.
Stat Med ; 40(24): 5174-5187, 2021 10 30.
Artículo en Inglés | MEDLINE | ID: mdl-34155676

RESUMEN

Approaches and guidelines for performing subgroup analysis to assess heterogeneity of treatment effect in clinical trials have been the topic of numerous papers in the statistical and clinical literature, but have been discussed predominantly in the context of conventional superiority trials. Concerns about treatment heterogeneity are the same if not greater in non-inferiority (NI) trials, especially since overall similarity between two treatment arms in a successful NI trial could be due to the existence of qualitative interactions that are more likely when comparing two active therapies. Even in unsuccessful NI trials, subgroup analyses can yield important insights about the potential reasons for failure to demonstrate non-inferiority of the experimental therapy. Recent NI trials have performed a priori subgroup analyses using standard statistical tests for interaction, but there is increasing interest in more flexible machine learning approaches for post-hoc subgroup discovery. The performance and practical application of such methods in NI trials have not been systematically explored, however. We considered the Virtual Twin method for the NI setting, an algorithm for subgroup identification that combines random forest with classification and regression trees, and conducted extensive simulation studies to examine its performance under different NI trial conditions and to devise decision rules for selecting the final subgroups. We illustrate the utility of the method with data from a NI trial that was conducted to compare two acupuncture treatments for chronic musculoskeletal pain.


Asunto(s)
Proyectos de Investigación , Simulación por Computador , Estudios de Equivalencia como Asunto , Humanos
2.
Ann Rheum Dis ; 79(2): 217-224, 2020 02.
Artículo en Inglés | MEDLINE | ID: mdl-31672776

RESUMEN

OBJECTIVES: Cardiac manifestations of neonatal lupus (NL) have been associated with significant morbidity and mortality; however, there is minimal information on long-term outcomes of affected individuals. This study was initiated to evaluate the presence of and the risk factors associated with cardiac dysfunction in NL after birth in multiple age groups to improve counselling, to further understand pathogenesis and to provide potential preventative strategies. METHODS: Echocardiogram reports were evaluated in 239 individuals with cardiac NL: 143 from age 0-1 year, 176 from age >1-17 years and 64 from age >17 years. Logistic regression analyses evaluated associations of cardiac dysfunction at each age group with demographic, fetal and postnatal factors, using imputation to address missing data. RESULTS: Cardiac dysfunction was identified in 22.4% at age 0-1 year, 14.8% at age >1-17 years and 28.1% at age >17 years. Dysfunction in various age groups was significantly associated with male sex, black race, lower fetal heart rates, fetal extranodal cardiac disease and length of time paced. In 106 children with echocardiograms at ages 0-1 year and >1-17 years, 43.8% with dysfunction at age 0-1 year were also affected at age >1-17 years, while the others reverted to normal. Of children without dysfunction at age 0-1 year, 8.9% developed new dysfunction between ages >1 and 17 years. Among 34 with echocardiograms at ages >1-17 years and >17 years, 6.5% with normal function at age >1-17 years developed dysfunction in adulthood. CONCLUSIONS: Risk factors in fetal life can influence cardiac morbidity into adulthood.Although limited by a small number of cases, cardiac dysfunction in the first year often normalises by later childhood. New-onset dysfunction, although rare, can occur de novo after the first year.


Asunto(s)
Ecocardiografía , Cardiopatías/diagnóstico por imagen , Lupus Eritematoso Sistémico/congénito , Factores de Tiempo , Adolescente , Adulto , Niño , Preescolar , Femenino , Cardiopatías/congénito , Humanos , Lactante , Recién Nacido , Modelos Logísticos , Lupus Eritematoso Sistémico/complicaciones , Lupus Eritematoso Sistémico/diagnóstico por imagen , Lupus Eritematoso Sistémico/fisiopatología , Masculino , Sistema de Registros , Factores de Riesgo , Adulto Joven
3.
Cancer Causes Control ; 30(4): 355-363, 2019 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-30788634

RESUMEN

BACKGROUND: Obesity is a strong risk factor for endometrial cancer, but it is unclear whether metabolic syndrome (MetS) contributes to endometrial cancer risk over and above the contribution of obesity. METHODS: We examined the association of MetS and its components with risk of endometrial cancer in a sub-cohort of 24,210 women enrolled in the Women's Health Initiative cohort study. Two variants of the National Cholesterol Education Program Adult Treatment Panel III definition of the MetS were used: one including and one excluding waist circumference (WC). Cox proportional hazards models were used to estimate the association of the study exposures with disease risk. RESULTS: When WC was included in the definition, MetS showed an approximately two-fold increase in endometrial cancer risk (HR 2.20; 95% CI 1.61-3.02); however, when WC was excluded, MetS was no longer associated with risk. We also observed that women with hyperglycemia, dyslipidemia and hypertension, in combination, had almost a twofold increased risk of endometrial cancer, independent of WC (HR 1.94; 95% CI 1.09, 3.46). Glucose, and, in particular, WC and body mass index were also positively associated with risk. CONCLUSIONS: Our findings suggest that MetS may predict risk of endometrial cancer independent of obesity among women with the remaining four Mets components.


Asunto(s)
Neoplasias Endometriales/epidemiología , Síndrome Metabólico/complicaciones , Obesidad/complicaciones , Posmenopausia , Anciano , Índice de Masa Corporal , Estudios de Cohortes , Dislipidemias/complicaciones , Femenino , Humanos , Hipertensión/complicaciones , Persona de Mediana Edad , Estudios Prospectivos , Factores de Riesgo , Circunferencia de la Cintura
5.
Int J Cancer ; 143(3): 543-551, 2018 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-29488210

RESUMEN

Obesity has been postulated to increase the risk of colorectal cancer by mechanisms involving insulin resistance and the metabolic syndrome. We examined the associations of body mass index (BMI), waist circumference, the metabolic syndrome, metabolic obesity phenotypes and homeostasis model-insulin resistance (HOMA-IR-a marker of insulin resistance) with risk of colorectal cancer in over 21,000 women in the Women's Health Initiative CVD Biomarkers subcohort. Women were cross-classified by BMI (18.5-<25.0, 25.0-<30.0 and ≥30.0 kg/m2 ) and presence of the metabolic syndrome into 6 phenotypes: metabolically healthy normal weight (MHNW), metabolically unhealthy normal weight (MUNW), metabolically healthy overweight (MHOW), metabolically unhealthy overweight (MUOW), metabolically healthy obese (MHO) and metabolically unhealthy obese (MUO). Neither BMI nor presence of the metabolic syndrome was associated with risk of colorectal cancer, whereas waist circumference showed a robust positive association. Relative to the MHNW phenotype, the MUNW phenotype was associated with increased risk, whereas no other phenotype showed an association. Furthermore, HOMA-IR was not associated with increased risk. Overall, our results do not support a direct role of metabolic dysregulation in the development of colorectal cancer; however, they do suggest that higher waist circumference is a risk factor, possibly reflecting the effects of increased levels of cytokines and hormones in visceral abdominal fat on colorectal carcinogenesis.


Asunto(s)
Neoplasias Colorrectales/epidemiología , Neoplasias Colorrectales/etiología , Síndrome Metabólico/complicaciones , Obesidad/complicaciones , Fenotipo , Anciano , Biomarcadores , Índice de Masa Corporal , Femenino , Estudios de Seguimiento , Humanos , Resistencia a la Insulina , Síndrome Metabólico/metabolismo , Persona de Mediana Edad , Obesidad/metabolismo , Oportunidad Relativa , Vigilancia de la Población , Posmenopausia , Medición de Riesgo , Factores de Riesgo
6.
Cancer Causes Control ; 29(1): 13-24, 2018 01.
Artículo en Inglés | MEDLINE | ID: mdl-29197994

RESUMEN

PURPOSE: Obesity, which is commonly accompanied by dyslipidemia, is associated with an increased risk of certain cancers. However, the association of serum lipids with specific obesity-related cancers is unclear. METHODS: We examined the association of baseline lipids (total cholesterol, low-density lipoprotein cholesterol [LDL-C], high-density lipoprotein cholesterol [HDL-C], and triglycerides) with risk of developing seven obesity-related cancers in a subcohort of 24,208 participants in the Women's Health Initiative. We used Cox proportional hazards models to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for quartiles of lipids with cancers of the breast, colorectum, pancreas, endometrium, ovary, and kidney, and multiple myeloma. RESULTS: Total cholesterol and LDL-C showed no association with these outcomes. HDL-C was inversely associated, and triglycerides were positively associated, with several cancers. However, after adjustment for other lipids or insulin, consideration of preclinical disease, and exclusion of women taking statins, most associations were attenuated and no longer significant. Only the inverse association of HDL-C with pancreatic cancer (HR for highest vs. lowest quartile 0.52, 95% CI 0.32-0.85, p for trend 0.007) and the positive association of triglycerides with kidney cancer (HR for highest vs. lowest quartile 3.21, 95% CI 1.63-6.33, p for trend = 0.0001) remained significant. However, the inverse association of HDL-C with pancreatic cancer was no longer significant when women who lost substantial weight before diagnosis were excluded. CONCLUSIONS: Our results suggest that when possible sources of confounding and bias are taken into account there are few robust associations of lipids with obesity-related cancers.


Asunto(s)
Lípidos/sangre , Neoplasias/etiología , Obesidad/sangre , Obesidad/complicaciones , Anciano , Dislipidemias/sangre , Dislipidemias/complicaciones , Femenino , Humanos , Persona de Mediana Edad , Posmenopausia , Modelos de Riesgos Proporcionales , Estudios Prospectivos , Factores de Riesgo
7.
Ann Rheum Dis ; 77(4): 549-555, 2018 04.
Artículo en Inglés | MEDLINE | ID: mdl-29371202

RESUMEN

OBJECTIVE: Studies in mouse models implicate complement activation as a causative factor in adverse pregnancy outcomes (APOs). We investigated whether activation of complement early in pregnancy predicts APOs in women with systemic lupus erythematosus (SLE) and/or antiphospholipid (aPL) antibodies. METHODS: The PROMISSE Study enrolled pregnant women with SLE and/or aPL antibodies (n=487) and pregnant healthy controls (n=204) at <12 weeks gestation and evaluated them monthly. APOs were: fetal/neonatal death, preterm delivery <36 weeks because of placental insufficiency or preeclampsia and/or growth restriction <5th percentile. Complement activation products were measured on serial blood samples obtained at each monthly visit. RESULTS: APO occurred in 20.5% of SLE and/or aPL pregnancies. As early as 12-15 weeks, levels of Bb and sC5b-9 were significantly higher in patients with APOs and remained elevated through 31 weeks compared with those with normal outcomes. Moreover, Bb and sC5b-9 were significantly higher in patients with SLE and/or aPL without APOs compared with healthy controls. In logistic regression analyses, Bb and sC5b-9 at 12-15 weeks remained significantly associated with APO (ORadj=1.41 per SD increase; 95% CI 1.06 to 1.89; P=0.019 and ORadj=1.37 per SD increase; 95% CI 1.05 to 1.80; P=0.022, respectively) after controlling for demographic and clinical risk factors for APOs in PROMISSE. When analyses were restricted to patients with aPL (n=161), associations between Bb at 12-15 weeks and APOs became stronger (ORadj=2.01 per SD increase; 95% CI 1.16 to 3.49; P=0.013). CONCLUSION: In pregnant patients with SLE and/or aPL, increased Bb and sC5b-9 detectable early in pregnancy are strongly predictive of APOs and support activation of complement, particularly the alternative pathway, as a contributor to APOs.


Asunto(s)
Anticuerpos Antifosfolípidos/inmunología , Activación de Complemento/inmunología , Lupus Eritematoso Sistémico/inmunología , Complicaciones del Embarazo/inmunología , Resultado del Embarazo , Adulto , Estudios de Casos y Controles , Factor B del Complemento/análisis , Factor B del Complemento/inmunología , Complejo de Ataque a Membrana del Sistema Complemento/análisis , Complejo de Ataque a Membrana del Sistema Complemento/inmunología , Femenino , Humanos , Embarazo
8.
Am J Epidemiol ; 186(1): 63-72, 2017 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-28369251

RESUMEN

White blood cell (WBC) count appears to predict total mortality and coronary heart disease (CHD) mortality, but it is unclear to what extent the association reflects confounding by smoking, underlying illness, or comorbid conditions. We used data from the Women's Health Initiative to examine the associations of WBC count with total mortality, CHD mortality, and cancer mortality. WBC count was measured at baseline in 160,117 postmenopausal women and again in year 3 in 74,375 participants. Participants were followed for a mean of 16 years. Cox proportional hazards models were used to estimate the relative mortality hazards associated with deciles of baseline WBC count and of the mean of baseline + year 3 WBC count. High deciles of both baseline and mean WBC count were positively associated with total mortality and CHD mortality, whereas the association with cancer mortality was weaker. The association of WBC count with mortality was independent of smoking and did not appear to be influenced by previous disease history. The potential clinical utility of this common laboratory test in predicting mortality risk warrants further study.


Asunto(s)
Enfermedad Coronaria/mortalidad , Recuento de Leucocitos/estadística & datos numéricos , Mortalidad , Neoplasias/mortalidad , Salud de la Mujer , Factores de Edad , Anciano , Causas de Muerte , Femenino , Conductas Relacionadas con la Salud , Estado de Salud , Humanos , Persona de Mediana Edad , Posmenopausia , Modelos de Riesgos Proporcionales , Estudios Prospectivos , Factores de Riesgo , Fumar/epidemiología , Factores Socioeconómicos , Estados Unidos
9.
BMC Med Res Methodol ; 17(1): 155, 2017 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-29191174

RESUMEN

BACKGROUND: The follow-up rate, a standard index of the completeness of follow-up, is important for assessing the validity of a cohort study. A common method for estimating the follow-up rate, the "Percentage Method", defined as the fraction of all enrollees who developed the event of interest or had complete follow-up, can severely underestimate the degree of follow-up. Alternatively, the median follow-up time does not indicate the completeness of follow-up, and the reverse Kaplan-Meier based method and Clark's Completeness Index (CCI) also have limitations. METHODS: We propose a new definition for the follow-up rate, the Person-Time Follow-up Rate (PTFR), which is the observed person-time divided by total person-time assuming no dropouts. The PTFR cannot be calculated directly since the event times for dropouts are not observed. Therefore, two estimation methods are proposed: a formal person-time method (FPT) in which the expected total follow-up time is calculated using the event rate estimated from the observed data, and a simplified person-time method (SPT) that avoids estimation of the event rate by assigning full follow-up time to all events. Simulations were conducted to measure the accuracy of each method, and each method was applied to a prostate cancer recurrence study dataset. RESULTS: Simulation results showed that the FPT has the highest accuracy overall. In most situations, the computationally simpler SPT and CCI methods are only slightly biased. When applied to a retrospective cohort study of cancer recurrence, the FPT, CCI and SPT showed substantially greater 5-year follow-up than the Percentage Method (92%, 92% and 93% vs 68%). CONCLUSIONS: The Person-time methods correct a systematic error in the standard Percentage Method for calculating follow-up rates. The easy to use SPT and CCI methods can be used in tandem to obtain an accurate and tight interval for PTFR. However, the FPT is recommended when event rates and dropout rates are high.


Asunto(s)
Estudios de Seguimiento , Algoritmos , Interpretación Estadística de Datos , Humanos , Estimación de Kaplan-Meier , Masculino , Recurrencia Local de Neoplasia/mortalidad , Neoplasias de la Próstata/mortalidad
10.
Am J Epidemiol ; 183(10): 911-9, 2016 05 15.
Artículo en Inglés | MEDLINE | ID: mdl-27076671

RESUMEN

Anemia and low and high levels of hemoglobin have been associated with increased mortality and morbidity. However, most studies have measured hemoglobin at only 1 time point, and few studies have considered possible reverse causation. We used data from the Women's Health Initiative, in which baseline hemoglobin was measured in 160,081 postmenopausal women and year 3 hemoglobin was measured in 75,658 participants, to examine the associations of hemoglobin concentration with total mortality, coronary heart disease mortality, and cancer mortality. Women were enrolled from 1993 to 1998 and followed for a median of 16 years. Cox proportional hazards models were used to estimate the relative mortality hazards associated with deciles of baseline hemoglobin and the mean of baseline + year 3 hemoglobin. Both low and high deciles of baseline hemoglobin were positively associated with all 3 outcomes in the total cohort. In analyses restricted to women with 2 measurements, a low mean hemoglobin level was robustly and positively associated with all 3 outcomes, after exclusion of the early years of follow-up. High mean hemoglobin was also associated with increased risk of total mortality, whereas associations with heart disease mortality and cancer mortality were weaker and inconsistent. Our results provide evidence that low and high levels of hemoglobin are associated with increased risk of mortality in otherwise healthy women.


Asunto(s)
Enfermedad Coronaria/mortalidad , Hemoglobinas/análisis , Mortalidad , Neoplasias/mortalidad , Posmenopausia/sangre , Factores de Edad , Anciano , Anemia/epidemiología , Índice de Masa Corporal , Femenino , Conductas Relacionadas con la Salud , Humanos , Persona de Mediana Edad , Modelos de Riesgos Proporcionales , Estudios Prospectivos , Factores de Riesgo , Fumar/epidemiología , Factores Socioeconómicos , Encuestas y Cuestionarios , Salud de la Mujer
11.
Ann Rheum Dis ; 75(6): 1161-5, 2016 06.
Artículo en Inglés | MEDLINE | ID: mdl-26835701

RESUMEN

OBJECTIVES: Extension of disease beyond the atrioventricular (AV) node is associated with increased mortality in cardiac neonatal lupus (NL). Treatment of isolated heart block with fluorinated steroids to prevent disease progression has been considered but published data are limited and discordant regarding efficacy. This study evaluated whether fluorinated steroids given to manage isolated advanced block prevented development of disease beyond the AV node and conferred a survival benefit. METHODS: In this retrospective study of cases enrolled in the Research Registry for NL, inclusion was restricted to anti-SSA/Ro-exposed cases presenting with isolated advanced heart block in utero who either received fluorinated steroids within 1 week of detection (N=71) or no treatment (N=85). Outcomes evaluated were: development of endocardial fibroelastosis, dilated cardiomyopathy and/or hydrops fetalis; mortality and pacemaker implantation. RESULTS: In Cox proportional hazards regression analyses, fluorinated steroids did not significantly prevent development of disease beyond the AV node (adjusted HR=0.90; 95% CI 0.43 to 1.85; p=0.77), reduce mortality (HR=1.63; 95% CI 0.43 to 6.14; p=0.47) or forestall/prevent pacemaker implantation (HR=0.87; 95% CI 0.57 to 1.33; p=0.53). No risk factors for development of disease beyond the AV node were identified. CONCLUSIONS: These data do not provide evidence to support the use of fluorinated steroids to prevent disease progression or death in cases presenting with isolated heart block.


Asunto(s)
Anticuerpos Antinucleares/sangre , Enfermedades Fetales/tratamiento farmacológico , Bloqueo Cardíaco/tratamiento farmacológico , Esteroides Fluorados/uso terapéutico , Adulto , Progresión de la Enfermedad , Femenino , Enfermedades Fetales/diagnóstico por imagen , Enfermedades Fetales/mortalidad , Bloqueo Cardíaco/congénito , Bloqueo Cardíaco/diagnóstico por imagen , Bloqueo Cardíaco/etiología , Bloqueo Cardíaco/mortalidad , Humanos , Recién Nacido , Estimación de Kaplan-Meier , Lupus Eritematoso Sistémico/complicaciones , Lupus Eritematoso Sistémico/congénito , Masculino , Marcapaso Artificial , Atención Prenatal/métodos , Sistema de Registros , Estudios Retrospectivos , Ultrasonografía Prenatal , Estados Unidos/epidemiología
12.
Am J Obstet Gynecol ; 214(1): 108.e1-108.e14, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-26432463

RESUMEN

BACKGROUND: Over 20% of pregnancies in patients with systemic lupus erythematosus (SLE) and/or antiphospholipid antibodies (APL) result in an adverse pregnancy outcome (APO) related to abnormal placentation. The ability to identify, early in pregnancy, patients who are destined for poor outcomes would significantly impact care of this high-risk population. In nonautoimmune patients, circulating angiogenic factors are dysregulated in disorders of placentation, such as preeclampsia (PE) and fetal growth restriction. OBJECTIVE: We sought to determine whether early dysregulation of circulating angiogenic factors can predict APO in high-risk SLE and/or APL pregnancies. STUDY DESIGN: We used data and samples from the Predictors of Pregnancy Outcome: Biomarkers in APL Syndrome and SLE (PROMISSE), a multicenter prospective study that enrolled 492 pregnant women with SLE and/or APL from September 2003 through August 2013. Patients were followed through pregnancy from <12 weeks gestation. Circulating levels of soluble fms-like tyrosine kinase-1 (sFlt1), placental growth factor (PlGF), and soluble endoglin were measured monthly and subjects followed up for APO, classified as severe (PE <34 weeks, fetal/neonatal death, indicated preterm delivery <30 weeks) or moderate (PE ≥34 weeks, indicated preterm delivery 30-36 weeks, growth restriction without PE). RESULTS: Severe APOs occurred in 12% and moderate APOs in 10% of patients. By 12-15 weeks, sFlt1, PlGF, and soluble endoglin levels were markedly altered in women who developed severe APO. After adjusting for clinical risk factors, sFlt1 was the strongest predictor of severe APO among 12-15 week measures (odds ratio, 17.3 comparing highest and lowest quartiles; 95% confidence interval [CI], 3.5-84.8; positive predictive value [PPV], 61%; negative predictive value [NPV], 93%). At 16-19 weeks, the combination of sFlt1 and PlGF was most predictive of severe APO, with risk greatest for subjects with both PlGF in lowest quartile (<70.3 pg/mL) and sFlt1 in highest quartile (>1872 pg/mL; odds ratio, 31.1; 95% CI, 8.0-121.9; PPV, 58%; NPV, 95%). Severe APO rate in this high-risk subgroup was 94% (95% CI, 70-99.8%), if lupus anticoagulant or history of high blood pressure was additionally present. In contrast, among patients with both sFlt1 <1872 pg/mL and PlGF >70.3 pg/mL, rate of severe APO was only 4.6% (95% CI, 2.1-8.6%). CONCLUSION: Circulating angiogenic factors measured during early gestation have a high NPV in ruling out the development of severe adverse outcomes among patients with SLE and/or APL syndrome. Timely risk stratification of patients is important for effective clinical care and optimal allocation of health care resources.


Asunto(s)
Antígenos CD/sangre , Síndrome Antifosfolípido/sangre , Retardo del Crecimiento Fetal/sangre , Lupus Eritematoso Sistémico/sangre , Preeclampsia/sangre , Proteínas Gestacionales/sangre , Receptores de Superficie Celular/sangre , Receptor 1 de Factores de Crecimiento Endotelial Vascular/sangre , Adulto , Antiinflamatorios no Esteroideos/uso terapéutico , Anticuerpos Antifosfolípidos/sangre , Anticoagulantes/uso terapéutico , Síndrome Antifosfolípido/tratamiento farmacológico , Aspirina/uso terapéutico , Biomarcadores/sangre , Endoglina , Femenino , Edad Gestacional , Heparina/uso terapéutico , Humanos , Lupus Eritematoso Sistémico/tratamiento farmacológico , Factor de Crecimiento Placentario , Valor Predictivo de las Pruebas , Embarazo , Resultado del Embarazo , Primer Trimestre del Embarazo/sangre , Segundo Trimestre del Embarazo/sangre , Embarazo de Alto Riesgo , Estudios Prospectivos , Índice de Severidad de la Enfermedad , Adulto Joven
13.
Ann Intern Med ; 163(3): 153-63, 2015 Aug 04.
Artículo en Inglés | MEDLINE | ID: mdl-26098843

RESUMEN

BACKGROUND: Because systemic lupus erythematosus (SLE) affects women of reproductive age, pregnancy is a major concern. OBJECTIVE: To identify predictors of adverse pregnancy outcomes (APOs) in patients with inactive or stable active SLE. DESIGN: Prospective cohort. SETTING: Multicenter. PATIENTS: 385 patients (49% non-Hispanic white; 31% with prior nephritis) with SLE in the PROMISSE (Predictors of Pregnancy Outcome: Biomarkers in Antiphospholipid Antibody Syndrome and Systemic Lupus Erythematosus) study. Exclusion criteria were urinary protein-creatinine ratio greater than 1000 mg/g, creatinine level greater than 1.2 mg/dL, prednisone use greater than 20 mg/d, and multifetal pregnancy. MEASUREMENTS: APOs included fetal or neonatal death; birth before 36 weeks due to placental insufficiency, hypertension, or preeclampsia; and small-for-gestational-age (SGA) neonate (birthweight below the fifth percentile). Disease activity was assessed with the Systemic Lupus Erythematosus Pregnancy Disease Activity Index and the Physician's Global Assessment (PGA). RESULTS: APOs occurred in 19.0% (95% CI, 15.2% to 23.2%) of pregnancies; fetal death occurred in 4%, neonatal death occurred in 1%, preterm delivery occurred in 9%, and SGA neonate occurred in 10%. Severe flares in the second and third trimesters occurred in 2.5% and 3.0%, respectively. Baseline predictors of APOs included presence of lupus anticoagulant (LAC) (odds ratio [OR], 8.32 [CI, 3.59 to 19.26]), antihypertensive use (OR, 7.05 [CI, 3.05 to 16.31]), PGA score greater than 1 (OR, 4.02 [CI, 1.84 to 8.82]), and low platelet count (OR, 1.33 [CI, 1.09 to 1.63] per decrease of 50 × 109 cells/L). Non-Hispanic white race was protective (OR, 0.45 [CI, 0.24 to 0.84]). Maternal flares, higher disease activity, and smaller increases in C3 level later in pregnancy also predicted APOs. Among women without baseline risk factors, the APO rate was 7.8%. For those who either were LAC-positive or were LAC-negative but nonwhite or Hispanic and using antihypertensives, the APO rate was 58.0% and fetal or neonatal mortality was 22.0%. LIMITATION: Patients with high disease activity were excluded. CONCLUSION: In pregnant patients with inactive or stable mild/moderate SLE, severe flares are infrequent and, absent specific risk factors, outcomes are favorable. PRIMARY FUNDING SOURCE: National Institutes of Health.


Asunto(s)
Lupus Eritematoso Sistémico/complicaciones , Complicaciones del Embarazo , Resultado del Embarazo , Adolescente , Adulto , Femenino , Muerte Fetal , Estudios de Seguimiento , Humanos , Lactante , Mortalidad Infantil , Recien Nacido Prematuro , Persona de Mediana Edad , Complicaciones del Trabajo de Parto , Embarazo , Estudios Prospectivos , Factores de Riesgo , Adulto Joven
14.
Cancer Causes Control ; 25(12): 1697-706, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-25307804

RESUMEN

PURPOSE: To examine the association of adult height with risk of cancer at different anatomic sites in a cohort of men and women. METHODS: The association of self-reported height with subsequent cancer risk was assessed in 288,683 men and 192,514 women enrolled in the National Institutes of Health-AARP Diet and Health Study. After a median follow-up of 10.5 years, incident cancer was diagnosed in 51,139 men and 23,407 women. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95 % confidence intervals (95 % CIs) for the association of height with cancer risk. RESULTS: After adjustment for covariates, height was positively associated with increased risk of all cancers combined in both men [HR10 cm increase = 1.05 (95 % CI 1.04-1.06)] and women [HR10 cm increase = 1.08 (95 % CI 1.06-1.10)]. Several sites common to men and women showed significant positive associations with height: colon, rectum, kidney, melanoma, and non-Hodgkin's lymphoma. For other shared sites, the association differed by sex. For still other sites, there was no clear association with height. Positive associations were also observed with cancers of the breast, endometrium, and prostate. CONCLUSIONS: Different patterns were observed in the height-cancer association by sex. Studies investigating the biological mechanisms underlying the association of height with cancer risk should focus on those sites that show a reproducible association with attained height.


Asunto(s)
Estatura , Dieta , Neoplasias/epidemiología , Anciano , Estudios de Cohortes , Femenino , Servicios de Salud para Ancianos , Humanos , Incidencia , Masculino , Persona de Mediana Edad , National Institutes of Health (U.S.) , Neoplasias/etiología , Modelos de Riesgos Proporcionales , Factores de Riesgo , Factores Sexuales , Encuestas y Cuestionarios , Estados Unidos/epidemiología
15.
Clin Trials ; 11(4): 503-507, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-24837325

RESUMEN

BACKGROUND: When randomizations are assigned at the cluster level for longitudinal cluster randomized trials (longitudinal-CRTs) with a continuous outcome, formulae for determining the required sample size to detect a two-way interaction effect between time and intervention are available. PURPOSE: To show that (1) those same formulae can also be applied to longitudinal trials when randomizations are assigned at the subject level within clusters and (2) this property can be extended to 2-by-2 factorial longitudinal-CRTs with two treatments and different levels of randomization for which testing a three-way interaction between time and the two interventions is of primary interest. METHODS: We show that slope estimates from different treatment arms are uncorrelated, regardless of whether randomization occurs at the third or second level and also regardless of whether slopes are considered fixed or random in the mixed-effects model for testing two-way or three-way interactions. Sample size formulae are extended to unbalanced designs. Simulation studies were applied to verify the findings. RESULTS: Sample size formulae for testing two-way and three-way interactions in longitudinal-CRTs with second-level randomization are identical to those for trials with third-level randomization. In addition, the total number of observations required for testing a three-way interaction is demonstrated to be four times as large as that required for testing a two-way interaction, regardless of the level of randomization for both fixed- and random-slope models. LIMITATIONS: The findings may be only applicable to longitudinal-CRTs with normally distributed continuous outcome. CONCLUSION: All of the findings are validated by simulation studies and enable the design of longitudinal clinical trials to be more flexible in regard to the level of randomization and allocation of clusters and subjects.

16.
J Biopharm Stat ; 24(3): 579-99, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24697506

RESUMEN

Clinical trials in the context of comparative effectiveness research (CER) are often conducted to evaluate health outcomes under real-world conditions and standard health care settings. In such settings, three-level hierarchical study designs are increasingly common. For example, patients may be nested within treating physicians, who in turn are nested within an urgent care center or hospital. While many trials randomize the third-level units (e.g., centers) to intervention, in some cases randomization may occur at lower levels of the hierarchy, such as patients or physicians. In this article, we present and verify explicit closed-form sample size and power formulas for three-level designs assuming randomization is at the first or second level. The formulas are based on maximum likelihood estimates from mixed-effect linear models and verified by simulation studies. Results indicate that even with smaller sample sizes, theoretical power derived with known variances is nearly identical to empirically estimated power for the more realistic setting when variances are unknown. In addition, we show that randomization at the second or first level of the hierarchy provides an increasingly statistically efficient alternative to third-level randomization. Power to detect a treatment effect under second-level randomization approaches that of patient-level randomization when there are few patients within each randomized second-level cluster and, most importantly, when the correlation attributable to second-level variation is a small proportion of the overall correlation between patient outcomes.


Asunto(s)
Modelos Estadísticos , Distribución Aleatoria , Ensayos Clínicos Controlados Aleatorios como Asunto/estadística & datos numéricos , Tamaño de la Muestra , Análisis por Conglomerados , Simulación por Computador , Humanos , Funciones de Verosimilitud
17.
Teach Learn Med ; 26(1): 64-71, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24405348

RESUMEN

BACKGROUND: The varying treatment of different patients by the same physician are referred to as within provider disparities. These differences can contribute to health disparities and are thought to be the result of implicit bias due to unintentional, unconscious assumptions. PURPOSES: The purpose is to describe an educational intervention addressing both health disparities and physician implicit bias and the results of a subsequent survey exploring medical students' attitudes and beliefs toward subconscious bias and health disparities. METHODS: A single session within a larger required course was devoted to health disparities and the physician's potential to contribute to health disparities through implicit bias. Following the session the students were anonymously surveyed on their Implicit Association Test (IAT) results, their attitudes and experiences regarding the fairness of the health care system, and the potential impact of their own implicit bias. The students were categorized based on whether they disagreed ("deniers") or agreed ("accepters") with the statement "Unconscious bias might affect some of my clinical decisions or behaviors." Data analysis focused specifically on factors associated with this perspective. RESULTS: The survey response rate was at least 69%. Of the responders, 22% were "deniers" and 77% were "accepters." Demographics between the two groups were not significantly different. Deniers were significantly more likely than accepters to report IAT results with implicit preferences toward self, to believe the IAT is invalid, and to believe that doctors and the health system provide equal care to all and were less likely to report having directly observed inequitable care. CONCLUSIONS: The recognition of bias cannot be taught in a single session. Our experience supports the value of teaching medical students to recognize their own implicit biases and develop skills to overcome them in each patient encounter, and in making this instruction part of the compulsory, longitudinal undergraduate medical curriculum.


Asunto(s)
Actitud del Personal de Salud , Disparidades en Atención de Salud , Prejuicio , Estudiantes de Medicina/psicología , Curriculum , Educación de Pregrado en Medicina , Femenino , Humanos , Masculino , Ciudad de Nueva York , Encuestas y Cuestionarios
18.
Arthritis Res Ther ; 26(1): 54, 2024 02 20.
Artículo en Inglés | MEDLINE | ID: mdl-38378664

RESUMEN

BACKGROUND: Leveraging the Accelerating Medicines Partnership (AMP) Lupus Nephritis (LN) dataset, we evaluated longitudinal patterns, rates, and predictors of response to standard-of-care therapy in patients with lupus nephritis. METHODS: Patients from US academic medical centers with class III, IV, and/or V LN and a baseline urine protein/creatinine (UPCR) ratio ≥ 1.0 (n = 180) were eligible for this analysis. Complete response (CR) required the following: (1) UPCR < 0.5; (2) normal serum creatinine (≤ 1.3 mg/dL) or, if abnormal, ≤ 125% of baseline; and (3) prednisone ≤ 10 mg/day. Partial response (PR) required the following: (1) > 50% reduction in UPCR; (2) normal serum creatinine or, if abnormal, ≤ 125% of baseline; and (3) prednisone dose ≤ 15 mg/day. RESULTS: Response rates to the standard of care at week 52 were CR = 22.2%; PR = 21.7%; non-responder (NR) = 41.7%, and not determined (ND) = 14.4%. Only 8/180 (4.4%) patients had a week 12 CR sustained through week 52. Eighteen (10%) patients attained a week 12 PR or CR and sustained their responses through week 52 and 47 (26.1%) patients achieved sustained PR or CR at weeks 26 and 52. Week 52 CR or PR attainment was associated with baseline UPCR > 3 (ORadj = 3.71 [95%CI = 1.34-10.24]; p = 0.012), > 25% decrease in UPCR from baseline to week 12 (ORadj = 2.61 [95%CI = 1.07-6.41]; p = 0.036), lower chronicity index (ORadj = 1.33 per unit decrease [95%CI = 1.10-1.62]; p = 0.003), and positive anti-dsDNA antibody (ORadj = 2.61 [95%CI = 0.93-7.33]; p = 0.069). CONCLUSIONS: CR and PR rates at week 52 were consistent with the standard-of-care response rates observed in prospective registrational LN trials. Low sustained response rates underscore the need for more efficacious therapies and highlight how critically important it is to understand the molecular pathways associated with response and non-response.


Asunto(s)
Nefritis Lúpica , Humanos , Nefritis Lúpica/tratamiento farmacológico , Inmunosupresores/uso terapéutico , Estudios Prospectivos , Creatinina , Prednisona/uso terapéutico , Resultado del Tratamiento , Inducción de Remisión , Estudios Retrospectivos , Riñón
19.
Circulation ; 126(1): 76-82, 2012 Jul 03.
Artículo en Inglés | MEDLINE | ID: mdl-22626746

RESUMEN

BACKGROUND: A recent case-control study suggested a benefit of hydroxychloroquine (HCQ) in lowering the risk of cardiac manifestations of neonatal lupus (cardiac-NL) in pregnancies of anti-SSA/Ro-positive patients with systemic lupus erythematosus. A historical cohort assembled from 3 international databases was used to evaluate whether HCQ reduces the nearly 10-fold increase in risk of recurrence of cardiac-NL independently of maternal health status. METHODS AND RESULTS: Two hundred fifty-seven pregnancies of anti-SSA/Ro-positive mothers (40 exposed and 217 unexposed to HCQ) subsequent to the birth of a child with cardiac-NL were identified from 3 databases (United States, England, and France). Exposure was defined as the sustained use of HCQ throughout pregnancy with initiation before 10 weeks of gestation. The recurrence rate of cardiac-NL in fetuses exposed to HCQ was 7.5% (3 of 40) compared with 21.2% (46 of 217) in the unexposed group (P=0.050). Although there were no deaths in the exposed group, the overall case fatality rate of the cardiac-NL fetuses in the unexposed group was 21.7%. In a multivariable analysis that adjusted for database source, maternal race/ethnicity, and anti-SSB/La status, HCQ use remained significantly associated with a decreased risk of cardiac-NL (odds ratio, 0.23; 95% confidence interval, 0.06-0.92; P=0.037). Similar results were obtained with propensity score analysis, an alternative approach to adjust for possible confounding by indication. CONCLUSION: Aggregate data from a multinational effort show that in mothers at high risk of having a child with cardiac-NL, the use of HCQ may protect against recurrence of disease in a subsequent pregnancy.


Asunto(s)
Anticuerpos Antinucleares/sangre , Hidroxicloroquina/uso terapéutico , Lupus Eritematoso Sistémico/congénito , Complicaciones Cardiovasculares del Embarazo/sangre , Complicaciones Cardiovasculares del Embarazo/prevención & control , Adulto , Estudios de Cohortes , Bases de Datos Factuales , Femenino , Francia/epidemiología , Humanos , Lupus Eritematoso Sistémico/sangre , Lupus Eritematoso Sistémico/epidemiología , Lupus Eritematoso Sistémico/prevención & control , Masculino , Embarazo , Complicaciones Cardiovasculares del Embarazo/epidemiología , Factores de Riesgo , Prevención Secundaria , Reino Unido/epidemiología , Estados Unidos/epidemiología
20.
J Immunol ; 187(1): 520-6, 2011 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-21602492

RESUMEN

One mechanism to molecularly explain the strong association of maternal anti-Ro60 Abs with cardiac disease in neonatal lupus (NL) is that these Abs initiate injury by binding to apoptotic cardiomyocytes in the fetal heart. Previous studies have demonstrated that ß(2)-glycoprotein I (ß(2)GPI) interacts with Ro60 on the surface of apoptotic Jurkat cells and prevents binding of anti-Ro60 IgG. Accordingly, the current study was initiated to test two complementary hypotheses, as follows: 1) competition between ß(2)GPI and maternal anti-Ro60 Abs for binding apoptotic induced surface-translocated Ro60 occurs on human fetal cardiomyocytes; and 2) circulating levels of ß(2)GPI influence injury in anti-Ro60-exposed fetuses. Initial flow cytometry experiments conducted on apoptotic human fetal cardiomyocytes demonstrated dose-dependent binding of ß(2)GPI. In competitive inhibition experiments, ß(2)GPI prevented opsonization of apoptotic cardiomyocytes by maternal anti-Ro60 IgG. ELISA was used to quantify ß(2)GPI in umbilical cord blood from 97 neonates exposed to anti-Ro60 Abs, 53 with cardiac NL and 44 with no cardiac disease. ß(2)GPI levels were significantly lower in neonates with cardiac NL. Plasmin-mediated cleavage of ß(2)GPI prevented binding to Ro60 and promoted the formation of pathogenic anti-Ro60 IgG-apoptotic cardiomyocyte complexes. In aggregate these data suggest that intact ß(2)GPI in the fetal circulation may be a novel cardioprotective factor in anti-Ro60-exposed pregnancies.


Asunto(s)
Anticuerpos Antinucleares/efectos adversos , Autoantígenos/inmunología , Miocitos Cardíacos/inmunología , Miocitos Cardíacos/patología , ARN Citoplasmático Pequeño/inmunología , Ribonucleoproteínas/inmunología , beta 2 Glicoproteína I/fisiología , beta 2 Glicoproteína I/uso terapéutico , Anticuerpos Antinucleares/metabolismo , Apoptosis/inmunología , Autoantígenos/metabolismo , Unión Competitiva/inmunología , Células Cultivadas , Femenino , Sangre Fetal/citología , Sangre Fetal/inmunología , Sangre Fetal/metabolismo , Fibrinolisina/metabolismo , Humanos , Inmunoglobulina G/efectos adversos , Inmunoglobulina G/metabolismo , Recién Nacido , Células Jurkat , Lupus Eritematoso Sistémico/congénito , Lupus Eritematoso Sistémico/inmunología , Lupus Eritematoso Sistémico/patología , Lupus Eritematoso Sistémico/terapia , Masculino , Miocitos Cardíacos/metabolismo , Unión Proteica/inmunología , ARN Citoplasmático Pequeño/metabolismo , Ribonucleoproteínas/metabolismo , beta 2 Glicoproteína I/metabolismo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA