Evaluation of risk equations for prediction of short-term coronary heart disease events in patients with long-standing type 2 diabetes: the Translating Research into Action for Diabetes (TRIAD) study.

BACKGROUND: To evaluate the U.K. Prospective Diabetes Study (UKPDS) and Framingham risk equations for predicting short-term risk of coronary heart disease (CHD) events among adults with long-standing type 2 diabetes, including those with and without preexisting CHD. METHODS: Prospective cohort of U.S. managed care enrollees aged ≥ 18 years and mean diabetes duration of more than 10 years, participating in the Translating Research into Action for Diabetes (TRIAD) study, was followed for the first occurrence of CHD events from 2000 to 2003. The UKPDS and Framingham risk equations were evaluated for discriminating power and calibration. RESULTS: A total of 8303 TRIAD participants, were identified to evaluate the UKPDS (n = 5914, 120 events), Framingham-initial (n = 5914, 218 events) and Framingham-secondary (n = 2389, 374 events) risk equations, according to their prior CHD history. All of these equations exhibited low discriminating power with Harrell's c-index <0.65. All except the Framingham-initial equation for women and the Framingham-secondary equation for men had low levels of calibration. After adjsusting for the average values of predictors and event rates in the TRIAD population, the calibration of these equations greatly improved. CONCLUSIONS: The UKPDS and Framingham risk equations may be inappropriate for predicting the short-term risk of CHD events in patients with long-standing type 2 diabetes, partly due to changes in medications used by patients with diabetes and other improvements in clinical care since the Frmaingham and UKPDS studies were conducted. Refinement of these equations to reflect contemporary CHD profiles, diagnostics and therapies are needed to provide reliable risk estimates to inform effective treatment.

Physicians' perceptions of barriers to cardiovascular disease risk factor control among patients with diabetes: results from the translating research into action for diabetes (TRIAD) study.

INTRODUCTION: Many patients with diabetes have poorly controlled blood glucose, lipid, or blood pressure levels, increasing their risk for cardiovascular disease (CVD) and other complications. Relatively little is known about what physicians perceive to be barriers to good CVD risk factor control or their own role in helping patients achieve good control. METHODS: We interviewed 34 primary care physicians in 4 states to assess their perceptions of patients' barriers to CVD risk factor control. Interviews were coded and analyzed for emergent themes. RESULTS: Physicians attributed barriers primarily to patients (socioeconomic issues, competing medical conditions, and lack of motivation) or to health system barriers (cost of care or lack of a multidisciplinary team). Physicians also expressed high levels of frustration with their efforts to address barriers. CONCLUSIONS: Physicians felt that barriers to CVD risk factor control often were beyond their abilities to address. Training physicians or other members of the primary health care team to address patients' personal barriers and health system barriers to good control could help alleviate high frustration levels, improve relationships with patients, and improve the treatment of diabetes. Supporting such efforts with adequate reimbursement should be a focus of health care reform.

Identifying risk factors for racial disparities in diabetes outcomes: the translating research into action for diabetes study.

BACKGROUND: Versus whites, blacks with diabetes have poorer control of hemoglobin A1c (HbA1c), higher systolic blood pressure (SBP), and higher low-density lipoprotein (LDL) cholesterol as well as higher rates of morbidity and microvascular complications. OBJECTIVE: To examine whether several mutable risk factors were more strongly associated with poor control of multiple intermediate outcomes among blacks with diabetes than among similar whites. DESIGN: Case-control study. SUBJECTS: A total of 764 blacks and whites with diabetes receiving care within 8 managed care health plans. MEASURES: Cases were patients with poor control of at least 2 of 3 intermediate outcomes (HbA1c > or =8.0%, SBP > or =140 mmHg, LDL cholesterol > or =130 mg/dL) and controls were patients with good control of all 3 (HbA1c <8.0%, SBP <140 mmHg, LDL cholesterol <130 mg/dL). In multivariate analyses, we determined whether each of several potentially mutable risk factors, including depression, poor adherence to medications, low self-efficacy for reducing cardiovascular risk, and poor patient-provider communication, predicted case or control status. RESULTS: Among blacks but not whites, in multivariate analyses depression (odds ratio: 2.28; 95% confidence interval: 1.09-4.75) and having missed medication doses (odds ratio: 1.96; 95% confidence interval: 1.01-3.81) were associated with greater odds of being a case rather than a control. None of the other risk factors were associated for either blacks or whites. CONCLUSIONS: Depression and missing medication doses are more strongly associated with poor diabetes control among blacks than in whites. These 2 risk factors may represent important targets for patient-level interventions to address racial disparities in diabetes outcomes.

Effect of sampling strategy on measures of VO2peak obtained using commercial breath-by-breath systems.

The purpose of this study was to determine the effect of sampling strategy (i.e., number of breaths) on measured peak rate of oxygen uptake ( VO(2peak)) elicited by a range of severe intensity exercise bouts. The hypothesis was that a smaller sample (i.e., fewer breaths) would produce a higher measure of VO(2peak) and that this effect would be greater in shorter tests than in longer tests. Thirty-three university students performed constant-power cycle ergometer tests at intensities selected to elicit fatigue in ~3.0 min (short duration), approximately 5.5 min (medium duration), and approximately 8.0 min (long duration). Values for VO(2peak) were the highest rates of oxygen uptake obtained using the following sampling methods: single breath, and 3-, 5-, 15- and 30-breath rolling averages. As hypothesized, measures of VO(2peak) increased systematically with decreasing sample size. Contrary to the hypothesis, the effect of sample size was greater in medium duration and long duration tests than in the short duration tests. The interaction between test duration and sample size on measures of VO(2peak) highlights the importance of standardizing the analysis protocol for exercise in the severe domain. If such standardization is not feasible, it should be recognized that specific analysis protocols may exert a substantial effect upon the reported VO(2peak).