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1.
Circ Res ; 120(12): 1947-1957, 2017 Jun 09.
Article in English | MEDLINE | ID: mdl-28490433

ABSTRACT

RATIONALE: Intracoronary infusion of bone marrow (BM) mononuclear cells after acute myocardial infarction (AMI) has led to limited improvement in left ventricular function. Although experimental AMI models have implicated cytokine-related impairment of progenitor cell function, this response has not been investigated in humans. OBJECTIVE: To test the hypothesis that peripheral blood (PB) cytokines predict BM endothelial progenitor cell colony outgrowth and cardiac function after AMI. METHODS AND RESULTS: BM and PB samples were collected from 87 participants 14 to 21 days after AMI and BM from healthy donors was used as a reference. Correlations between cytokine concentrations and cell phenotypes, cell functions, and post-AMI cardiac function were determined. PB interleukin-6 (IL-6) negatively correlated with endothelial colony-forming cell colony maximum in the BM of patients with AMI (estimate±SE, -0.13±0.05; P=0.007). BM from healthy individuals showed a dose-dependent decrease in endothelial colony-forming cell colony outgrowth in the presence of exogenous IL-1ß or IL-6 (P<0.05). Blocking the IL-1R or IL-6R reversed cytokine impairment. In AMI study participants, the angiogenic cytokine platelet-derived growth factor BB glycoprotein correlated positively with BM-derived colony-forming unit-endothelial colony maximum (estimate±SE, 0.01±0.002; P<0.001), multipotent mesenchymal stromal cell colony maximum (estimate±SE, 0.01±0.002; P=0.002) in BM, and mesenchymal stromal cell colony maximum in PB (estimate±SE, 0.02±0.005; P<0.001). CONCLUSIONS: Two weeks after AMI, increased PB platelet-derived growth factor BB glycoprotein was associated with increased BM function, whereas increased IL-6 was associated with BM impairment. Validation studies confirmed inflammatory cytokine impairment of BM that could be reversed by blocking IL-1R or IL-6R. Together, these studies suggest that blocking IL-1 or IL-6 receptors may improve the regenerative capacity of BM cells after AMI. CLINICAL TRIAL REGISTRATIONS: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00684060.


Subject(s)
Bone Marrow Cells/physiology , Cytokines/blood , Interleukin-1beta/blood , Interleukin-6/blood , Myocardial Infarction/blood , Bone Marrow/physiology , Cells, Cultured , Female , Humans , Male , Middle Aged , Myocardial Infarction/diagnosis
2.
Stat Med ; 38(18): O3505, 2019 08 15.
Article in English | MEDLINE | ID: mdl-30900282

ABSTRACT

Withdrawal: Shuster, JJ, Handler, M. How to investigate an accused serial sexual harasser. Statistics in Medicine. 2019; 1-4. https://doi.org/10.1002/sim.8145. The above article from Statistics in Medicine, published online on 21 March 2019 in Wiley Online Library (http://wileyonlinelibrary.com) has been withdrawn by agreement of the authors, the Journal Editors (Ralph D'Agostino, Simon Day, Els Goetghebeur and Joel Greenhouse) and John Wiley & Sons Ltd. The editors acknowledge that the original manuscript did not undergo the rigorous peer-review process that is customarily expected of a scholarly journal.

3.
Health Commun ; 33(12): 1410-1424, 2018 12.
Article in English | MEDLINE | ID: mdl-28872905

ABSTRACT

Many people living with Chronic Obstructive Pulmonary Disease (COPD) have low general health literacy; however, there is little information available on these patients' eHealth literacy, or their ability to seek, find, understand, and appraise online health information and apply this knowledge to address or solve disease-related health concerns. A nationally representative sample of patients registered in the COPD Foundation's National Research Registry (N = 1,270) was invited to complete a web-based survey to assess socio-demographic (age, gender, marital status, education), health status (generic and lung-specific health-related quality of life), and socio-cognitive (social support, self-efficacy, COPD knowledge) predictors of eHealth literacy, measured using the 8-item eHealth literacy scale (eHEALS). Over 50% of the respondents (n = 176) were female (n = 89), with a mean age of 66.19 (SD = 9.47). Overall, participants reported moderate levels of eHealth literacy, with more than 70% feeling confident in their ability to find helpful health resources on the Internet. However, respondents were much less confident in their ability to distinguish between high- and low-quality sources of web-based health information. Very severe versus less severe COPD (ß = 4.15), lower lung-specific health-related quality of life (ß = -0.19), and greater COPD knowledge (ß = 0.62) were significantly associated with higher eHealth literacy. Higher COPD knowledge was also significantly associated with greater knowledge (ρ = 0.24, p = .001) and use (ρ = 0.24, p = .001) of web-based health resources. Findings emphasize the importance of integrating skill-building activities into comprehensive patient education programs that enable patients with severe cases of COPD to identify high-quality sources of web-based health information. Additional research is needed to understand how new social technologies can be used to help medically underserved COPD patients benefit from web-based self-management support resources.


Subject(s)
Health Knowledge, Attitudes, Practice , Health Literacy , Information Seeking Behavior , Pulmonary Disease, Chronic Obstructive/psychology , Adult , Aged , Aged, 80 and over , Female , Health Literacy/statistics & numerical data , Humans , Internet , Linear Models , Male , Middle Aged , Patients , Quality of Life , Registries , Surveys and Questionnaires , Telemedicine
4.
Stat Med ; 36(24): 3910-3918, 2017 Oct 30.
Article in English | MEDLINE | ID: mdl-28685497

ABSTRACT

Before learning anything about statistical inference in beginning service courses in biostatistics, students learn how to calculate the mean and variance of linear combinations of random variables. Practical precalculus examples of the importance of these exercises can be helpful for instructors, the target audience of this paper. We shall present applications to the "1-sample" and "2-sample" methods for randomized short-term 2-treatment crossover studies, where patients experience both treatments in random order with a "washout" between the active treatment periods. First, we show that the 2-sample method is preferred as it eliminates "conditional bias" when sample sizes by order differ and produces a smaller variance. We also demonstrate that it is usually advisable to use the differences in posttests (ignoring baseline and post washout values) rather than the differences between the changes in treatment from the start of the period to the end of the period ("delta of delta"). Although the intent is not to provide a definitive discussion of crossover designs, we provide a section and references to excellent alternative methods, where instructors can provide motivation to students to explore the topic in greater detail in future readings or courses.


Subject(s)
Cross-Over Studies , Randomized Controlled Trials as Topic/methods , Biostatistics/methods , Humans , Linear Models , Research Design , Sample Size , Treatment Outcome
5.
Pediatr Diabetes ; 18(4): 311-314, 2017 06.
Article in English | MEDLINE | ID: mdl-27174580

ABSTRACT

OBJECTIVE: To determine the effects of omitting meal time insulin on arterial stiffness in children with type 1 diabetes. RESEARCH DESIGN AND METHODS: In this prospective, randomized, crossover study, radial artery tonometry and augmentation index adjusted to heart rate 75 (AI75 ) were used to measure arterial stiffness. Children were randomized to receive or omit premeal insulin and completed the crossover portion of the study on a subsequent day. AI75 was determined when fasting, 1, and 2 h postmeal. RESULTS: When comparing change in AI75 from baseline to 1 h and baseline to 2 h, when subjects received premeal insulin vs. no insulin, AI75 was 4.5 units lower at 1 h (p = 0.011, 95% CI:1.1 lower to 8 lower) and 4.3 units lower at 2 h (p = 0.062, 95% CI: 0.2 higher to 8.9 lower) (n = 40). CONCLUSIONS: Arterial stiffness is decreased by premeal insulin in children with type 1 diabetes.


Subject(s)
Diabetes Mellitus, Type 1/drug therapy , Diabetic Angiopathies/prevention & control , Hyperglycemia/prevention & control , Hypoglycemic Agents/administration & dosage , Insulin/administration & dosage , Meals , Vascular Stiffness/drug effects , Adolescent , Cardiovascular Diseases/complications , Cardiovascular Diseases/epidemiology , Cardiovascular Diseases/prevention & control , Child , Cross-Over Studies , Diabetes Mellitus, Type 1/blood , Diabetes Mellitus, Type 1/complications , Diabetic Angiopathies/epidemiology , Diabetic Cardiomyopathies/epidemiology , Diabetic Cardiomyopathies/prevention & control , Drug Administration Schedule , Female , Florida/epidemiology , Glycated Hemoglobin/analysis , Humans , Hypoglycemic Agents/therapeutic use , Insulin/therapeutic use , Male , Radial Artery , Risk
6.
Childs Nerv Syst ; 33(2): 329-335, 2017 Feb.
Article in English | MEDLINE | ID: mdl-27988879

ABSTRACT

INTRODUCTION: Therapeutic hypothermia for the treatment of moderate to severe neonatal hypoxic ischemic encephalopathy has been shown to reduce death and disability, but the effects on seizures after discharge from the Neonatal ICU are not known. METHODS: A retrospective cohort study was conducted involving 56 neonates admitted to the Neonatal ICU at Children's Hospital of Orange County, CA from January 1, 2007 to September 1, 2013 with hypoxic ischemic encephalopathy who met criteria for selective brain cooling. Fifteen patients received supportive care. Forty-one patients received cooling, of whom 25 were included for analysis. Sixteen patients from the hypothermia group and 12 from the no hypothermia group developed clinical seizures while inpatient. Up to 6 months, four patients (16%) had continued seizures in the therapeutic hypothermia group compared to eight (53%) patients who did not receive hypothermia. DISCUSSION: Our study shows an association between therapeutic hypothermia and reduced seizures after discharge from the neonatal intensive care unit. The short duration of follow-up, 6 months, is a limitation of this study. Another limitation is its observational nature, where reasons for treatment selection and exclusions are unmeasurable confounding factors. Further studies are needed to determine long-term effects.


Subject(s)
Hypothermia, Induced/methods , Hypoxia-Ischemia, Brain/complications , Intensive Care Units, Neonatal , Patient Discharge/statistics & numerical data , Seizures/complications , Seizures/therapy , Child, Preschool , Cohort Studies , Female , Humans , Infant , Infant, Newborn , Male
7.
Eur Heart J ; 37(19): 1504-13, 2016 05 14.
Article in English | MEDLINE | ID: mdl-26614823

ABSTRACT

AIMS: The mechanistic basis of the symptoms and signs of myocardial ischaemia in patients without obstructive coronary artery disease (CAD) and evidence of coronary microvascular dysfunction (CMD) is unclear. The aim of this study was to mechanistically test short-term late sodium current inhibition (ranolazine) in such subjects on angina, myocardial perfusion reserve index, and diastolic filling. MATERIALS AND RESULTS: Randomized, double-blind, placebo-controlled, crossover, mechanistic trial in subjects with evidence of CMD [invasive coronary reactivity testing or non-invasive cardiac magnetic resonance imaging myocardial perfusion reserve index (MPRI)]. Short-term oral ranolazine 500-1000 mg twice daily for 2 weeks vs. placebo. Angina measured by Seattle Angina Questionnaire (SAQ) and SAQ-7 (co-primaries), diary angina (secondary), stress MPRI, diastolic filling, quality of life (QoL). Of 128 (96% women) subjects, no treatment differences in the outcomes were observed. Peak heart rate was lower during pharmacological stress during ranolazine (-3.55 b.p.m., P < 0.001). The change in SAQ-7 directly correlated with the change in MPRI (correlation 0.25, P = 0.005). The change in MPRI predicted the change in SAQ QoL, adjusted for body mass index (BMI), prior myocardial infarction, and site (P = 0.0032). Low coronary flow reserve (CFR <2.5) subjects improved MPRI (P < 0.0137), SAQ angina frequency (P = 0.027), and SAQ-7 (P = 0.041). CONCLUSIONS: In this mechanistic trial among symptomatic subjects, no obstructive CAD, short-term late sodium current inhibition was not generally effective for SAQ angina. Angina and myocardial perfusion reserve changes were related, supporting the notion that strategies to improve ischaemia should be tested in these subjects. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01342029.


Subject(s)
Myocardial Ischemia/drug therapy , Ranolazine/administration & dosage , Sodium Channel Blockers/administration & dosage , Administration, Oral , Angina Pectoris/drug therapy , Angina Pectoris/physiopathology , Coronary Disease/drug therapy , Coronary Disease/physiopathology , Cross-Over Studies , Double-Blind Method , Drug Administration Schedule , Female , Hemodynamics/physiology , Humans , Magnetic Resonance Angiography , Male , Medication Adherence , Microvessels , Middle Aged , Quality of Life , Ranolazine/adverse effects , Sodium Channel Blockers/adverse effects , Treatment Outcome
8.
Diabetologia ; 59(1): 217-221, 2016 Jan.
Article in English | MEDLINE | ID: mdl-26358584

ABSTRACT

AIMS/HYPOTHESIS: Previous studies of pancreases obtained at autopsy or by radiography note reduced pancreas weight (PW) and size, respectively, in type 1 diabetes; this finding is widely considered to be the result of chronic insulinopenia. This literature is, however, limited with respect to the influence of age, sex, anthropometric factors and disease duration on these observations. Moreover, data are sparse for young children, a group of particular interest for type 1 diabetes. We hypothesised that the pancreas-to-body weight ratio would normalise confounding inter-subject factors, thereby permitting better characterisation of PW in type 1 diabetes. METHODS: Transplant-grade pancreases were recovered from 216 organ donors with type 1 diabetes (n = 90), type 2 diabetes (n = 40) and no diabetes (n = 86). Whole-organ and head, body and tail weights were determined. The relative PW (RPW; PW [g] / body weight [kg]) was calculated and tested for normalisation of potential differences due to age, sex and BMI. RESULTS: PW significantly correlated with body weight in control donors (R (2) = 0.76, p < 0.001) while RPW (1.03 ± 0.36, mean ± SD) did not significantly differ across ages (0-58 years). Donors with type 1 diabetes (0.57 ± 0.18, p < 0.001), but not those with type 2 diabetes (0.93 ± 0.30), had significantly lower RPW. The relative weights of each pancreatic region from donors with type 1 diabetes were significantly smaller than those of regions from control donors and donors with type 2 diabetes (p < 0.001). Perhaps most interestingly, the RPW was not significantly associated with duration of type 1 diabetes or type 2 diabetes. CONCLUSIONS/INTERPRETATION: RPW allows for comparisons across a wide range of donor ages by eliminating confounding variables. These data validate an interesting feature of the type 1 diabetes pancreas and underscore the need for additional studies to identify the mechanistic basis for this finding, including those beyond the chronic loss of endogenous insulin secretion.


Subject(s)
Diabetes Mellitus, Type 1/physiopathology , Pancreas/physiopathology , Adolescent , Adult , Age Factors , Anthropometry , Autopsy , Body Mass Index , Body Weight , Child , Child, Preschool , Diabetes Mellitus, Type 2/physiopathology , Female , Humans , Infant , Infant, Newborn , Male , Middle Aged , Organ Size , Young Adult
9.
Stat Med ; 35(14): 2467-78, 2016 06 30.
Article in English | MEDLINE | ID: mdl-26728099

ABSTRACT

Meta-analysis of clinical trials is a methodology to summarize information from a collection of trials about an intervention, in order to make informed inferences about that intervention. Random effects allow the target population outcomes to vary among trials. Since meta-analysis is often an important element in helping shape public health policy, society depends on biostatisticians to help ensure that the methodology is sound. Yet when meta-analysis involves randomized binomial trials with low event rates, the overwhelming majority of publications use methods currently not intended for such data. This statistical practice issue must be addressed. Proper methods exist, but they are rarely applied. This tutorial is devoted to estimating a well-defined overall relative risk, via a patient-weighted random-effects method. We show what goes wrong with methods based on 'inverse-variance' weights, which are almost universally used. To illustrate similarities and differences, we contrast our methods, inverse-variance methods, and the published results (usually inverse-variance) for 18 meta-analyses from 13 Journal of the American Medical Association articles. We also consider the 2007 case of rosiglitazone (Avandia), where important public health issues were at stake, involving patient cardiovascular risk. The most widely used method would have reached a different conclusion. © 2016 The Authors. Statistics in Medicine published by John Wiley & Sons Ltd.


Subject(s)
Clinical Trials as Topic/statistics & numerical data , Meta-Analysis as Topic , Biostatistics , Cardiovascular Diseases/etiology , Diabetes Mellitus, Type 2/drug therapy , Humans , Hypoglycemic Agents/adverse effects , Models, Statistical , Risk , Risk Factors , Rosiglitazone , Thiazolidinediones/adverse effects
10.
Stat Med ; 35(20): 3537-48, 2016 09 10.
Article in English | MEDLINE | ID: mdl-26999553

ABSTRACT

Propensity score (PS) methods have been used extensively to adjust for confounding factors in the statistical analysis of observational data in comparative effectiveness research. There are four major PS-based adjustment approaches: PS matching, PS stratification, covariate adjustment by PS, and PS-based inverse probability weighting. Though covariate adjustment by PS is one of the most frequently used PS-based methods in clinical research, the conventional variance estimation of the treatment effects estimate under covariate adjustment by PS is biased. As Stampf et al. have shown, this bias in variance estimation is likely to lead to invalid statistical inference and could result in erroneous public health conclusions (e.g., food and drug safety and adverse events surveillance). To address this issue, we propose a two-stage analytic procedure to develop a valid variance estimator for the covariate adjustment by PS analysis strategy. We also carry out a simple empirical bootstrap resampling scheme. Both proposed procedures are implemented in an R function for public use. Extensive simulation results demonstrate the bias in the conventional variance estimator and show that both proposed variance estimators offer valid estimates for the true variance, and they are robust to complex confounding structures. The proposed methods are illustrated for a post-surgery pain study. Copyright © 2016 John Wiley & Sons, Ltd.


Subject(s)
Confounding Factors, Epidemiologic , Propensity Score , Bias , Humans , Observational Studies as Topic
11.
J Nucl Cardiol ; 23(4): 680-9, 2016 08.
Article in English | MEDLINE | ID: mdl-26253327

ABSTRACT

BACKGROUND: The relationship between inappropriate MPI and cardiovascular outcomes is poorly understood. We sought to systematically review the literature on appropriate use criteria (AUC) for MPI, including temporal trend of inappropriate testing and resulting cardiovascular outcomes. METHODS: We searched the MEDLINE database for studies related to AUC and MPI. The co-primary outcomes were abnormal test results and the presence of cardiac ischemia. Random effects odds ratios (OR) were constructed using DerSimonian-Laird method. RESULTS: A total of 22 studies with 23,443 patients were included. The prevalence of inappropriate testing was 14.8% [95% confidence interval (CI) 11.6%-18.7%]. Inappropriate MPI studies were less likely to be abnormal (OR 0.41 95% CI 0.35-0.49, P < .0001) and to demonstrate ischemia (OR 0.40, 95% CI 0.24-0.67, P < .0001) compared to appropriate testing. No difference in the rate of inappropriate tests was detected based on the midpoint of the enrollment year (P = .54). The pattern of ordering inappropriate studies was not different between cardiology and non-cardiology providers (OR 0.74, 95% CI 0.51-1.06, P = .10). CONCLUSION: Inappropriate MPI studies are less likely to yield abnormal results or demonstrate myocardial ischemia. The rate of inappropriate MPI has not decreased over time.


Subject(s)
Diagnostic Errors/statistics & numerical data , Myocardial Ischemia/diagnosis , Myocardial Ischemia/epidemiology , Myocardial Perfusion Imaging/statistics & numerical data , Tomography, Emission-Computed, Single-Photon/statistics & numerical data , Unnecessary Procedures/statistics & numerical data , Unnecessary Procedures/trends , Aged , Diagnostic Errors/prevention & control , Female , Humans , MEDLINE/statistics & numerical data , Male , Middle Aged , Prevalence , Reproducibility of Results , Risk Factors , Sensitivity and Specificity , Utilization Review
12.
Pharmacoepidemiol Drug Saf ; 25(6): 678-86, 2016 06.
Article in English | MEDLINE | ID: mdl-26597624

ABSTRACT

PURPOSE: To explore changes in stimulant utilization and pre-treatment electrocardiography (ECG) screening in response to cardiovascular (CV) safety concerns. METHODS: Two source populations were established from Florida Medicaid Fee-for-service beneficiaries between 2001 and 2008: approximately 44 571 newly diagnosed attention deficit/hyperactivity disorder patients and 33 000 new stimulant users. Time-series design and Joinpoint analysis were used to describe monthly trend changes in stimulant initiation, persistence, dosing, and pre-treatment ECG screening. RESULTS: Initial and maintenance daily dose declined 6 mg (95% confidence interval [CI] -14 to -1.9) methylphenidate (MPH) equivalent dose from a steady 27 mg after Canada withdrew Adderall XR in February 2005; the trend rebounded to a daily dose of 23 mg, after the remarketing of Adderall XR and a debate in the US over issuing a boxed warning on stimulant CV safety in early 2006. Monthly initiation increased 3.9% (CI -1.0 to 9.1) after the boxed warning debate to 54 per 100 patients per month (CI 44 to 68), but declined 2.4% (CI -3.6 to -1.2) after requirement of medication guides in February 2007. Monthly ECG screening increased 3.2% (CI 2.3 to 4.2) after Adderall XR withdrawal and further increased 13% (CI 4 to 23) after the American Heart Association recommended pre-treatment ECG screening to 40 per 100 patients per month (CI 17 to 48). CONCLUSIONS: The first signal of stimulant CV safety concerns was followed by varying responses depending on the outcome measure used, suggesting that patients and physicians responded at different times after the publicity of safety concerns. Clinical consequences of the changes are uncertain. Copyright © 2015 John Wiley & Sons, Ltd.


Subject(s)
Attention Deficit Disorder with Hyperactivity/drug therapy , Cardiovascular Diseases/prevention & control , Central Nervous System Stimulants/administration & dosage , Methylphenidate/administration & dosage , Amphetamines/administration & dosage , Amphetamines/adverse effects , Cardiovascular Diseases/chemically induced , Central Nervous System Stimulants/adverse effects , Child , Dose-Response Relationship, Drug , Drug Labeling , Electrocardiography/methods , Female , Florida , Humans , Male , Medicaid , Methylphenidate/adverse effects , Outcome Assessment, Health Care , Time Factors , United States
13.
Am J Med Genet A ; 167A(1): 69-79, 2015 Jan.
Article in English | MEDLINE | ID: mdl-25355237

ABSTRACT

Circulating total ghrelin levels are elevated in older children and adults with Prader-Willi syndrome (PWS). However, the presence or absence of hyperghrelinemia in young children with PWS remains controversial. We hypothesized that a more robust way to analyze appetite-regulating hormones in PWS would be by nutritional phases rather than age alone. Our objectives were to compare total serum ghrelin levels in children with PWS by nutritional phase as well as to compare total ghrelin levels in PWS (5 weeks to 21 years of age) to normal weight controls and individuals with early-onset morbid obesity (EMO) without PWS. Fasting serum total ghrelin levels were measured in 60 subjects with PWS, 39 subjects with EMO of unknown etiology, and in 95 normal non-obese sibling controls of PWS or EMO subjects (SibC) in this 12 year longitudinal study. Within PWS, total ghrelin levels were significantly (P < 0.001) higher in earlier nutritional phases: phase 1a (7,906 ± 5,887); 1b (5,057 ± 2,624); 2a (2,905 ± 1,521); 2b (2,615 ± 1,370) and 3 (2,423 ± 1,350). Young infants with PWS also had significantly (P = 0.009) higher total ghrelin levels than did the sibling controls. Nutritional phase is an important independent prognostic factor of total ghrelin levels in individuals with PWS. Circulating ghrelin levels are elevated in young children with PWS long before the onset of hyperphagia, especially during the early phase of poor appetite and feeding. Therefore, it seems unlikely that high ghrelin levels are directly responsible for the switch to the hyperphagic nutritional phases in PWS.


Subject(s)
Ghrelin/blood , Hyperphagia/blood , Prader-Willi Syndrome/blood , Age Distribution , Child , Child, Preschool , Fasting/blood , Female , Humans , Infant , Insulin Resistance , Male , Obesity, Morbid/blood , Prader-Willi Syndrome/classification , Siblings , Young Adult
14.
Stat Med ; 34(10): 1621-33, 2015 May 10.
Article in English | MEDLINE | ID: mdl-25645442

ABSTRACT

Repeated measurement designs have been widely used in various randomized controlled trials for evaluating long-term intervention efficacies. For some clinical trials, the primary research question is how to compare two treatments at a fixed time, using a t-test. Although simple, robust, and convenient, this type of analysis fails to utilize a large amount of collected information. Alternatively, the mixed-effects model is commonly used for repeated measurement data. It models all available data jointly and allows explicit assessment of the overall treatment effects across the entire time spectrum. In this paper, we propose an analytic strategy for longitudinal clinical trial data where the mixed-effects model is coupled with a model selection scheme. The proposed test statistics not only make full use of all available data but also utilize the information from the optimal model deemed for the data. The performance of the proposed method under various setups, including different data missing mechanisms, is evaluated via extensive Monte Carlo simulations. Our numerical results demonstrate that the proposed analytic procedure is more powerful than the t-test when the primary interest is to test for the treatment effect at the last time point. Simulations also reveal that the proposed method outperforms the usual mixed-effects model for testing the overall treatment effects across time. In addition, the proposed framework is more robust and flexible in dealing with missing data compared with several competing methods. The utility of the proposed method is demonstrated by analyzing a clinical trial on the cognitive effect of testosterone in geriatric men with low baseline testosterone levels.


Subject(s)
Models, Statistical , Randomized Controlled Trials as Topic/statistics & numerical data , Research Design/statistics & numerical data , Aged , Analysis of Variance , Androgens/pharmacology , Bias , Cognition/drug effects , Computer Simulation , Data Interpretation, Statistical , Humans , Longitudinal Studies , Male , Randomized Controlled Trials as Topic/methods , Randomized Controlled Trials as Topic/standards , Research Design/standards , Testosterone/pharmacology
15.
Ann Allergy Asthma Immunol ; 114(1): 58-62.e2, 2015 Jan.
Article in English | MEDLINE | ID: mdl-25528738

ABSTRACT

BACKGROUND: Omalizumab, an anti-IgE monoclonal antibody, is administered by injection once or twice monthly in offices and clinics. It offers a potential alternative intervention for patients with allergic asthma that is not well controlled because of recalcitrant poor adherence to inhaled corticosteroid therapy. OBJECTIVE: To assess the effect of omalizumab therapy by measuring airway responsiveness to adenosine, a marker of allergic airway inflammation, and resource use. METHODS: Patients (N = 17) aged 6 to 26 years (mean age, 16.4 years) with poorly controlled persistent allergic asthma, less than 50% adherence to inhaled corticosteroid therapy, a forced expiratory volume in 1 second (FEV1) of 60% predicted or higher, and adenosine provocation concentration that caused a decrease in FEV1 of 20% (PC20) of 60 mg/mL or less were randomized to receive 4 months of omalizumab or placebo in a double-blind, crossover trial with a 3- to 4-month washout between treatments. Patients were instructed to continue taking inhaled corticosteroids throughout the study. The PC20 was measured before and after each period. RESULTS: Fifteen patients completed the study. The mean baseline PC20 was 14.1 mg/mL (95% CI, 10.8-18.4 mg/mL). The fold change PC20 was 0.9 (95% CI, 0.5-1.7) during placebo and 3.1 (95% CI, 1.6-6.2) during omalizumab treatment; the estimated ratio was 3.4 (95% CI, 1.2-9.3; P = .02). Six patients required one or more short courses of oral corticosteroids for asthma exacerbations during placebo, but none required this intervention during omalizumab. During the study, the median prescription refills for inhaled corticosteroids was 0.15 (95% CI, 0.00-0.33) canisters per month. CONCLUSION: Omalizumab therapy is an alternative for patients with more severe poorly controlled asthma in whom adherence does not improve with conventional interventions. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00133042.


Subject(s)
Adrenal Cortex Hormones/therapeutic use , Antibodies, Anti-Idiotypic/administration & dosage , Antibodies, Monoclonal, Humanized/administration & dosage , Asthma/drug therapy , Administration, Inhalation , Adolescent , Adult , Antibodies, Anti-Idiotypic/adverse effects , Antibodies, Monoclonal, Humanized/adverse effects , Child , Cross-Over Studies , Double-Blind Method , Female , Humans , Male , Medication Adherence , Omalizumab , United States , Young Adult
16.
Am J Physiol Endocrinol Metab ; 307(5): E456-61, 2014 Sep 01.
Article in English | MEDLINE | ID: mdl-25074984

ABSTRACT

Testosterone (T) stimulates erythropoiesis and regulates iron homeostasis. However, it remains unknown whether the (type II) 5α-reduction of T to dihydrotestosterone (DHT) mediates these androgenic effects, as it does in some other tissues. Our purpose was to determine whether inhibition of type II 5α-reductase (via finasteride) alters red blood cell (RBC) production and serum markers of iron homeostasis subsequent to testosterone-enanthate (TE) administration in older hypogonadal men. Sixty men aged ≥60 yr with serum T <300 ng/dl or bioavailable T <70 ng/dl received treatment with TE (125 mg/wk) vs. vehicle paired with finasteride (5 mg/day) vs. placebo using a 2 × 2 factorial design. Over the course of 12 mo, TE increased RBC count 9%, hematocrit 4%, and hemoglobin 8% while suppressing serum hepcidin 57% (P < 0.001 for all measurements). Most of the aforementioned changes occurred in the first 3 mo of treatment, and finasteride coadministration did not significantly alter any of these effects. TE also reduced serum ferritin 32% (P = 0.002) within 3 mo of treatment initiation without altering iron, transferrin, or transferrin saturation. We conclude that TE stimulates erythropoiesis and alters iron homeostasis independently of the type II 5α-reductase enzyme. These results demonstrate that elevated DHT is not required for androgen-mediated erythropoiesis or for alterations in iron homeostasis that would appear to support iron incorporation into RBCs.


Subject(s)
Dihydrotestosterone/metabolism , Erythrocytes/drug effects , Erythrocytes/metabolism , Iron/metabolism , Testosterone/analogs & derivatives , Aged , Aged, 80 and over , Double-Blind Method , Drug Interactions , Erythrocyte Count , Ferritins/blood , Finasteride/pharmacology , Humans , Iron/blood , Male , Middle Aged , Placebos , Testosterone/pharmacology , Transferrin/analysis
17.
Am J Physiol Endocrinol Metab ; 306(4): E433-42, 2014 Feb 15.
Article in English | MEDLINE | ID: mdl-24326421

ABSTRACT

Testosterone acts directly at androgen receptors and also exerts potent actions following 5α-reduction to dihydrotestosterone (DHT). Finasteride (type II 5α-reductase inhibitor) lowers DHT and is used to treat benign prostatic hyperplasia. However, it is unknown whether elevated DHT mediates either beneficial musculoskeletal effects or prostate enlargement resulting from higher-than-replacement doses of testosterone. Our purpose was to determine whether administration of testosterone plus finasteride to older hypogonadal men could produce musculoskeletal benefits without prostate enlargement. Sixty men aged ≥60 yr with a serum testosterone concentration of ≤300 ng/dl or bioavailable testosterone ≤70 ng/dl received 52 wk of treatment with testosterone enanthate (TE; 125 mg/wk) vs. vehicle, paired with finasteride (5 mg/day) vs. placebo using a 2 × 2 factorial design. Over the course of 12 mo, TE increased upper and lower body muscle strength by 8-14% (P = 0.015 to <0.001), fat-free mass 4.04 kg (P = 0.032), lumbar spine bone mineral density (BMD) 4.19% (P < 0.001), and total hip BMD 1.96% (P = 0.024) while reducing total body fat -3.87 kg (P < 0.001) and trunk fat -1.88 kg (P = 0.0051). In the first 3 mo, testosterone increased hematocrit 4.13% (P < 0.001). Coadministration of finasteride did not alter any of these effects. Over 12 mo, testosterone also increased prostate volume 11.4 cm(3) (P = 0.0051), an effect that was completely prevented by finasteride (P = 0.0027). We conclude that a higher-than-replacement TE combined with finasteride significantly increases muscle strength and BMD and reduces body fat without causing prostate enlargement. These results demonstrate that elevated DHT mediates testosterone-induced prostate enlargement but is not required for benefits in musculoskeletal or adipose tissue.


Subject(s)
Bone Density/drug effects , Finasteride/therapeutic use , Hypogonadism/drug therapy , Muscle, Skeletal/drug effects , Prostate/drug effects , Testosterone/analogs & derivatives , Aged , Body Composition/drug effects , Drug Therapy, Combination , Finasteride/pharmacology , Humans , Male , Middle Aged , Muscle Strength/drug effects , Testosterone/pharmacology , Testosterone/therapeutic use , Treatment Outcome
18.
BMC Med ; 12: 211, 2014 Nov 27.
Article in English | MEDLINE | ID: mdl-25428524

ABSTRACT

BACKGROUND: Potential cardiovascular (CV) risks of testosterone replacement therapy (TRT) are currently a topic of intense interest. However, no studies have addressed CV risk as a function of the route of administration of TRT. METHODS: Two meta-analyses were conducted, one of CV adverse events (AEs) in 35 randomized controlled trials (RCTs) of TRT lasting 12 weeks or more, and one of 32 studies reporting the effect of TRT on serum testosterone and dihydrotestosterone (DHT). RESULTS: CV risks of TRT: Of 2,313 studies identified, 35 were eligible and included 3,703 mostly older men who experienced 218 CV-related AEs. No significant risk for CV AEs was present when all TRT administration routes were grouped (relative risk (RR) = 1.28, 95% confidence interval (CI): 0.76 to 2.13, P = 0.34). When analyzed separately, oral TRT produced significant CV risk (RR = 2.20, 95% CI: 1.45 to 3.55, P = 0.015), while neither intramuscular (RR = 0.66, 95% CI: 0.28 to 1.56, P = 0.32) nor transdermal (gel or patch) TRT (RR = 1.27, 95% CI: 0.62 to 2.62, P = 0.48) significantly altered CV risk. Serum testosterone/DHT following TRT: Of 419 studies identified, 32 were eligible which included 1,152 men receiving TRT. No significant difference in the elevation of serum testosterone was present between intramuscular or transdermal TRT. However, transdermal TRT elevated serum DHT (5.46-fold, 95% CI: 4.51 to 6.60) to a greater magnitude than intramuscular TRT (2.20-fold, 95% CI: 1.74 to 2.77). CONCLUSIONS: Oral TRT produces significant CV risk. While no significant effects on CV risk were observed with either injected or transdermal TRT, the point estimates suggest that further research is needed to establish whether administration by these routes is protective or detrimental, respectively. Differences in the degree to which serum DHT is elevated may underlie the varying CV risk by TRT administration route, as elevated serum dihydrotestosterone has been shown to be associated with CV risk in observational studies.


Subject(s)
Cardiovascular Diseases/etiology , Dihydrotestosterone/blood , Testosterone/administration & dosage , Administration, Cutaneous , Adult , Cardiovascular Diseases/blood , Hormone Replacement Therapy , Humans , Injections, Intramuscular , Male , Randomized Controlled Trials as Topic , Risk Factors
19.
J Pediatr Hematol Oncol ; 36(5): 353-61, 2014 Jul.
Article in English | MEDLINE | ID: mdl-24608079

ABSTRACT

PURPOSE: To determine the efficacy and toxicity of higher dose versus standard dose intravenous methotrexate (MTX) and pulses of high-dose cytosine arabinoside with asparaginase versus standard dose cytosine arabinoside and teniposide during intensified continuation therapy for higher risk pediatric B-precursor acute lymphoblastic leukemia (ALL). PATIENTS AND METHODS: From 1994 to 1999, the Pediatric Oncology Group conducted a randomized phase III clinical trial in higher risk pediatric B-precursor ALL. A total of 784 patients were randomized in a 2×2 factorial design to receive MTX 1 g/m versus 2.5 g/m and to cytosine arabinoside/teniposide versus high-dose cytosine arabinoside/asparaginase during intensified continuation therapy. RESULTS: Patients receiving standard dose MTX had a 5-year disease-free survival (DFS) of 71.8±2.4%; patients receiving higher dose MTX had a 5-year DFS of 71.7±2.4% (P=0.55). Outcomes on cytosine arabinoside/teniposide (DFS of 70.4±2.4) were similar to higher dose cytosine arabinoside/asparaginase (DFS of 73.1±2.3%) (P=0.41). Overall survival rates were not different between MTX doses or cytosine arabinoside/teniposide versus cytosine arabinoside/asparaginase. CONCLUSIONS: Increasing MTX dosing to 2.5 g/m did not improve outcomes in higher risk pediatric B-precursor ALL. Giving high-dose cytarabine and asparaginase pulses instead of standard dose cytarabine and teniposide produced nonsignificant differences in outcomes, allowing for teniposide to be removed from ALL therapy.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Precursor Cell Lymphoblastic Leukemia-Lymphoma/drug therapy , Asparaginase/administration & dosage , Child , Cytarabine/administration & dosage , Dose-Response Relationship, Drug , Female , Follow-Up Studies , Humans , Male , Methotrexate/administration & dosage , Precursor Cell Lymphoblastic Leukemia-Lymphoma/mortality , Precursor Cell Lymphoblastic Leukemia-Lymphoma/pathology , Prognosis , Remission Induction , Risk Factors , Survival Rate , Teniposide/administration & dosage
20.
Postgrad Med J ; 90(1069): 630-7, 2014 Nov.
Article in English | MEDLINE | ID: mdl-25214540

ABSTRACT

BACKGROUND/OBJECTIVES: Obesity has been declared a 21st century pandemic by WHO. Yet surveys reveal physicians-in-training are uncomfortable managing obesity. One major barrier is the lack of residency education on obesity management. This study incorporates an obesity-specific didactic curriculum into an internal medicine (IM) residency programme and assesses its impact on residents' knowledge, attitudes, practice behaviours, and clinical outcomes in patients with obesity. METHODS: The intervention consisted of four, 1 h, obesity-specific lectures in the University of Florida Resident Noon Conference. Lectures were taught by multidisciplinary experts and offered to 75 IM residents every 2 weeks from 5 November 2010 to 17 December 2010. Impact on IM residents' knowledge and attitudes was assessed by a pre- and post-intervention Obesity Awareness Questionnaire (OAQ). IM residents' clinical performance was assessed by chart reviews of 238 patients with body mass index >25 kg/m(2) in residents' clinics 4 months pre- and 6 months post-intervention for three clinical outcomes and seven practice behaviours on obesity management. Pre- and post-intervention outcomes were compared via paired t tests (quantitative data) or McNemar's test (binary data). RESULTS: Mean lecture attendance was 25/75 residents (33%) per lecture. Survey response was 67/75 residents (89%) pre-OAQ and 63/75 residents (84%) post-OAQ. While most attitudes remained unchanged, IM residents gained significant confidence in exercise counselling, safety of bariatric surgery, and patients' weight loss potential; they were more likely to address obesity in the plan and referrals to bariatric surgery. Clinical outcomes and IM residents' knowledge demonstrated no improvement. CONCLUSIONS: Our brief lecture-based curriculum has the potential to improve IM residents' attitudes and practice behaviours towards obesity. The lack of improvement in clinical outcomes and resident knowledge prompts the need for multimodal, longitudinal curricula with experiential application of obesity medicine.


Subject(s)
Health Knowledge, Attitudes, Practice , Internship and Residency/methods , Obesity/psychology , Chronic Disease/rehabilitation , Curriculum , Education, Medical, Graduate , Educational Measurement , Humans , Obesity/therapy
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