End-Digit Preference and the Quality of Blood Pressure Monitoring in Diabetic Adults

OBJECTIVE: Although tight blood pressure (BP) control is proven to reduce diabetes-related cardiovascular risk, it has been difficult to achieve in practice, perhaps in part because of low-quality monitoring data. We hypothesized that low-quality BP data, reflected in end-digit preference (EDP), remains common in primary care of diabetic adults. RESEARCH DESIGN AND METHODS: Data were abstracted from the charts of 404 adults with type 2 diabetes seen at 16 academically affiliated clinics from 1999 to 2001. End-digits of systolic and diastolic BPs taken with nonautomated sphygmomanometers were extracted, and prevalence of EDP for zero was calculated. Associations between EDP and selected patient characteristics were determined using multiple logistic regressions. RESULTS: EDP was highly prevalent in the BP measurements taken by nonphysicians (4,333 BPs; 50% of systolic, 50% of diastolic readings ended in zero; P < 0.001) and physicians (1,347 BPs; 69% of systolic, 64% of diastolic readings ended in zero; P < 0.001). In multivariate analysis, nonphysicians showed greater EDP for systolic BP in older patients (odds ratio OR 1.07 per 5 years) and women (OR 1.36 vs. men) and for diastolic BP in African-Americans (OR 1.25 vs. whites; all P < 0.05); physicians showed greater EDP for diastolic BP in less obese patients (OR 0.97 per 5 kg/m2 increment in BMI; P = 0.02). CONCLUSIONS: Low-quality BP measurement is common in primary care of diabetic adults. Procedural and technological improvements to BP measurement deserve attention as part of an overall strategy to tighten BP control and reduce cardiovascular risk.