James H. Ware

Bio: James H. Ware is an academic researcher from Harvard University. The author has contributed to research in topics: Randomized controlled trial & Population. The author has an hindex of 73, co-authored 149 publications receiving 30966 citations.

An Association between Air Pollution and Mortality in Six U.S. Cities

Abstract: Background Recent studies have reported associations between particulate air pollution and daily mortality rates. Population-based, cross-sectional studies of metropolitan areas in the United States have also found associations between particulate air pollution and annual mortality rates, but these studies have been criticized, in part because they did not directly control for cigarette smoking and other health risks. Methods In this prospective cohort study, we estimated the effects of air pollution on mortality, while controlling for individual risk factors. Survival analysis, including Cox proportional-hazards regression modeling, was conducted with data from a 14-to-16-year mortality follow-up of 8111 adults in six U.S. cities. Results Mortality rates were most strongly associated with cigarette smoking. After adjusting for smoking and other risk factors, we observed statistically significant and robust associations between air pollution and mortality. The adjusted mortality-rate ratio for the most po...

Applied Longitudinal Analysis

Abstract: Preface.Acknowledgments.PART I: INTRODUCTION TO LONGITUDINAL AND CLUSTERED DATA.1. Longitudinal and Clustered Data.2. Longitudinal Data: Basic Concepts.PART II: LINEAR MODELS FOR LONGITUDINAL CONTINUOUS DATA.3. Overview of Linear Models for Longitudinal Data.4. Estimation and Statistical Inference.5. Modelling the Mean: Analyzing Response Profiles.6. Modelling the Mean: Parametric Curves.7. Modelling the Covariance.8. Linear Mixed Effects Models.9. Residual Analyses and Diagnostics.PART III: GENERALIZED LINEAR MODELS FOR LONGITUDINAL DATA.10. Review of Generalized Linear Models.11. Marginal Models: Generalized Estimating Equations (GEE).12. Generalized Linear Mixed Effects Models.13. Contrasting Marginal and Mixed Effects Models.PART IV: ADVANCED TOPICS FOR LONGITUDINAL AND CLUSTERED DATA.14. Missing Data and Dropout.15. Some Aspects of the Design of Longitudinal Studies.16. Repeated Measures and Related Designs.17. Multilevel Models.Appendix A: Gentle Introduction to Vectors and Matrices.Appendix B: Properties of Expectations and Variances.Appendix C: Critical Points for a 50:50 Mixture of Chi-Squared Distributions.References.Index.

Bivalirudin for Patients with Acute Coronary Syndromes

Abstract: Bivalirudin plus a glycoprotein IIb/IIIa inhibitor, as compared with heparin plus a glycoprotein IIb/IIIa inhibitor, was associated with noninferior 30-day rates of the composite ischemia end point (7.7% and 7.3%, respectively), major bleeding (5.3% and 5.7%), and the net clinical outcome end point (11.8% and 11.7%). Bivalirudin alone, as compared with heparin plus a glycoprotein IIb/IIIa inhibitor, was associated with a noninferior rate of the composite ischemia end point (7.8% and 7.3%, respectively; P = 0.32; relative risk, 1.08; 95% confidence interval [CI], 0.93 to 1.24) and significantly reduced rates of major bleeding (3.0% vs. 5.7%; P<0.001; relative risk, 0.53; 95% CI, 0.43 to 0.65) and the net clinical outcome end point (10.1% vs. 11.7%; P = 0.02; relative risk, 0.86; 95% CI, 0.77 to 0.97). Conclusions In patients with moderate- or high-risk acute coronary syndromes who were undergoing invasive treatment with glycoprotein IIb/IIIa inhibitors, bivalirudin was associated with rates of ischemia and bleeding that were similar to those with heparin. Bivalirudin alone was associated with similar rates of ischemia and significantly lower rates of bleeding. (ClinicalTrials.gov number, NCT00093158.)

Statistics in Medicine — Reporting of Subgroup Analyses in Clinical Trials

Abstract: The analysis of subgroups is often used as a way to glean additional information from data sets. The strengths and weaknesses of this approach and new Journal policies concerning the reporting of subgroup analyses are discussed in this article.

Physical activity, including walking, and cognitive function in older women.

Abstract: ContextPhysical activity may help maintain cognitive function in older adults.ObjectiveTo examine the relation of long-term regular physical activity, including walking, to cognitive function.DesignWomen reported participation in leisure-time physical activities on biennial mailed questionnaires beginning in 1986. We assessed long-term activity by averaging energy expenditures from questionnaires in 1986 through participants' baseline cognitive assessments (1995 to 2001). We used linear regression to estimate adjusted mean differences in baseline cognitive performance and cognitive decline over 2 years, across levels of physical activity and walking.Setting and ParticipantsNurses' Health Study, including 18 766 US women aged 70 to 81 years.Main Outcome MeasureValidated telephone assessments of cognition administered twice approximately 2 years apart (1995 to 2001 and 1997 to 2003), including tests of general cognition, verbal memory, category fluency, and attention.ResultsHigher levels of activity were associated with better cognitive performance. On a global score combining results of all 6 tests, women in the second through fifth quintiles of energy expenditure scored an average of 0.06, 0.06, 0.09, and 0.10 standard units higher than women in the lowest quintile (P for trend <.001). Compared with women in the lowest physical activity quintile, we found a 20% lower risk of cognitive impairment for women in the highest quintile of activity. Among women performing the equivalent of walking at an easy pace for at least 1.5 h/wk, mean global scores were 0.06 to 0.07 units higher compared with walking less than 40 min/wk (P≤.003). We also observed less cognitive decline among women who were more active, especially those in the 2 highest quintiles of energy expenditure. Women in the fourth and fifth quintiles had mean changes in global scores that were 0.04 (95% confidence interval, 0.02-0.10) and 0.06 (95% confidence interval, 0.02-0.11) standard units better than those in the lowest quintile.ConclusionLong-term regular physical activity, including walking, is associated with significantly better cognitive function and less cognitive decline in older women.

Longitudinal data analysis using generalized linear models

Abstract: SUMMARY This paper proposes an extension of generalized linear models to the analysis of longitudinal data. We introduce a class of estimating equations that give consistent estimates of the regression parameters and of their variance under mild assumptions about the time dependence. The estimating equations are derived without specifying the joint distribution of a subject's observations yet they reduce to the score equations for multivariate Gaussian outcomes. Asymptotic theory is presented for the general class of estimators. Specific cases in which we assume independence, m-dependence and exchangeable correlation structures from each subject are discussed. Efficiency of the proposed estimators in two simple situations is considered. The approach is closely related to quasi-likelih ood. Some key ironh: Estimating equation; Generalized linear model; Longitudinal data; Quasi-likelihood; Repeated measures.

Ventilation with lower tidal volumes as compared with traditional tidal volumes for acute lung injury and the acute respiratory distress syndrome.

Abstract: Background Traditional approaches to mechanical ventilation use tidal volumes of 10 to 15 ml per kilogram of body weight and may cause stretch-induced lung injury in patients with acute lung injury and the acute respiratory distress syndrome. We therefore conducted a trial to determine whether ventilation with lower tidal volumes would improve the clinical outcomes in these patients. Methods Patients with acute lung injury and the acute respiratory distress syndrome were enrolled in a multicenter, randomized trial. The trial compared traditional ventilation treatment, which involved an initial tidal volume of 12 ml per kilogram of predicted body weight and an airway pressure measured after a 0.5-second pause at the end of inspiration (plateau pressure) of 50 cm of water or less, with ventilation with a lower tidal volume, which involved an initial tidal volume of 6 ml per kilogram of predicted body weight and a plateau pressure of 30 cm of water or less. The primary outcomes were death before a patient was discharged home and was breathing without assistance and the number of days without ventilator use from day 1 to day 28. Results The trial was stopped after the enrollment of 861 patients because mortality was lower in the group treated with lower tidal volumes than in the group treated with traditional tidal volumes (31.0 percent vs. 39.8 percent, P=0.007), and the number of days without ventilator use during the first 28 days after randomization was greater in this group (mean [+/-SD], 12+/-11 vs. 10+/-11; P=0.007). The mean tidal volumes on days 1 to 3 were 6.2+/-0.8 and 11.8+/-0.8 ml per kilogram of predicted body weight (P Conclusions In patients with acute lung injury and the acute respiratory distress syndrome, mechanical ventilation with a lower tidal volume than is traditionally used results in decreased mortality and increases the number of days without ventilator use.

Standards of Medical Care in Diabetes

Abstract: XI. STRATEGIES FOR IMPROVING DIABETES CARE D iabetes is a chronic illness that requires continuing medical care and patient self-management education to prevent acute complications and to reduce the risk of long-term complications. Diabetes care is complex and requires that many issues, beyond glycemic control, be addressed. A large body of evidence exists that supports a range of interventions to improve diabetes outcomes. These standards of care are intended to provide clinicians, patients, researchers, payors, and other interested individuals with the components of diabetes care, treatment goals, and tools to evaluate the quality of care. While individual preferences, comorbidities, and other patient factors may require modification of goals, targets that are desirable for most patients with diabetes are provided. These standards are not intended to preclude more extensive evaluation and management of the patient by other specialists as needed. For more detailed information, refer to Bode (Ed.): Medical Management of Type 1 Diabetes (1), Burant (Ed): Medical Management of Type 2 Diabetes (2), and Klingensmith (Ed): Intensive Diabetes Management (3). The recommendations included are diagnostic and therapeutic actions that are known or believed to favorably affect health outcomes of patients with diabetes. A grading system (Table 1), developed by the American Diabetes Association (ADA) and modeled after existing methods, was utilized to clarify and codify the evidence that forms the basis for the recommendations. The level of evidence that supports each recommendation is listed after each recommendation using the letters A, B, C, or E.

ACC/AHA 2006 Guidelines for the Management of Patients With Valvular Heart Disease

Abstract: PREAMBLE......e4 APPENDIX 1......e121 APPENDIX 2......e122 APPENDIX 3......e124 REFERENCES......e124 It is important that the medical profession play a significant role in critically evaluating the use of diagnostic procedures and therapies as they are introduced in the detection, management,