Who's really hypertensive?--Quality control issues in the assessment of blood pressure for randomized trials.

The characterization of blood pressure in treatment trials assessing the benefits of blood pressure lowering regimens is a critical factor for the appropriate interpretation of study results. With numerous operators involved in the measurement of blood pressure in many thousands of patients being screened for entry into clinical trials, it is essential that operators follow pre-defined measurement protocols involving multiple measurements and standardized techniques. Blood pressure measurement protocols have been developed by international societies and emphasize the importance of appropriate choice of cuff size, identification of Korotkoff sounds, and digit preference. Training of operators and auditing of blood pressure measurement may assist in reducing the operator-related errors in measurement. This paper describes the quality control activities adopted for the screening stage of the 2nd Australian National Blood Pressure Study (ANBP2). ANBP2 is cardiovascular outcome trial of the treatment of hypertension in the elderly that was conducted entirely in general practices in Australia. A total of 54 288 subjects were screened; 3688 previously untreated subjects were identified as having blood pressure >140/90 mmHg at the initial screening visit, 898 (24%) were not eligible for study entry after two further visits due to the elevated reading not being sustained. For both systolic and diastolic blood pressure recording, observed digit preference fell within 7 percentage points of the expected frequency. Protocol adherence, in terms of the required minimum blood pressure difference between the last two successive recordings, was 99.8%. These data suggest that adherence to blood pressure recording protocols and elimination of digit preferences can be achieved through appropriate training programs and quality control activities in large multi-centre community-based trials in general practice. Repeated blood pressure measurement prior to initial diagnosis and study entry is essential to appropriately characterize hypertension in these elderly patients.

The effect of alcohol intake on insulin sensitivity in men: a randomized controlled trial.

OBJECTIVE: Population data suggest that alcohol consumption may influence the risk of diabetes in a biphasic manner, but this has not been tested by any controlled interventions. The object of this study was to determine whether reducing alcohol intake in moderate-to-heavy drinkers (40-110 g/day) results in improvement in insulin sensitivity. RESEARCH DESIGN AND METHODS: A 4-week run-in period where subjects maintained their usual drinking pattern was followed by randomization to a two-way cross-over intervention study. In each of two 4-week treatment interventions, subjects either substituted their usual alcohol intake with a 0.9% alcohol beer or maintained their usual alcohol intake. At the end of each 4-week period, insulin sensitivity as determined by the low-dose insulin glucose infusion test and the homeostasis model assessment (HOMA) score, and biomarkers of alcohol consumption (gamma-glutamyl transpeptidase [gamma-GT] and HDL cholesterol) were measured. RESULTS: A total of 16 healthy men aged 51.0 +/- 2.7 (mean +/- SEM) years with a BMI of 26.4 +/- 0.61 kg/m(2) completed the study. There was a large reduction in alcohol intake (72.4 +/- 5.0 vs. 7.9 +/- 1.6 g/day, P < 0.001) and significant reductions in gamma-GT (geometric mean 24.4 units/l [95% CI 19.7-30.2] vs. 18.6 units/l [15.5-22.2], P < 0.01) and HDL cholesterol (1.36 +/- 0.07 vs. 1.13 +/- 0.07 mmol/l, P < 0.001). There was no effect of alcohol on insulin sensitivity index (ISI), fasting insulin, glucose, or HOMA score. CONCLUSIONS: A substantial reduction in alcohol intake from 7.2 to 0.8 standard drinks per day in healthy men did not change insulin sensitivity as measured by ISI or HOMA score.