Encounter frequency and blood pressure in hypertensive patients with diabetes mellitus.

The relationship between encounter frequency (average number of provider-patient encounters over a period of time) and blood pressure for hypertensive patients is unknown. We tested the hypothesis that shorter encounter intervals are associated with faster blood pressure normalization. We performed a retrospective cohort study of 5042 hypertensive patients with diabetes mellitus treated at primary care practices affiliated with 2 academic hospitals between 2000 and 2005. Distinct periods of continuously elevated blood pressure (>or=130/85 mm Hg) were studied. We evaluated the association of the average encounter interval with time to blood pressure normalization and rate of blood pressure decrease. Blood pressure of the patients with the average interval between encounters <or=1 month normalized after a median of 1.5 months at the rate of 28.7 mm Hg/month compared with 12.2 months at 2.6 mm Hg/month for the encounter interval >1 month (P<0.0001 for all). Median time to blood pressure normalization was 0.7 versus 1.9 months for the average encounter interval <or=2 weeks versus between 2 weeks and 1 month, respectively (P<0.0001). In proportional hazards analysis adjusted for patient demographics, initial blood pressure, and treatment intensification rate, a 1 month increase in the average encounter interval was associated with a hazard ratio of 0.764 for blood pressure normalization (P<0.0001). Shorter encounter intervals are associated with faster decrease in blood pressure and earlier blood pressure normalization. Greatest benefits were observed at encounter intervals (<or=2 weeks) shorter than what is currently recommended.