Influence of Obesity on Blood Pressure Responses to Antihypertensive Drug Therapy in an Urban Hypertension Specialty Clinic

BACKGROUND: Previous studies have reported that lean hypertensives have worse clinical outcomes than obese hypertensives as obesity confers pharmacological resistance to antihypertensive therapy. We explored whether the higher prescribed doses of antihypertensives in obese hypertensives were adequate for the attainment of similar on-treatment blood pressure (BP) versus leaner hypertensives. METHODS: A retrospective chart review of predominantly African American females from a deidentified urban referral clinic was conducted (N = 851; median follow-up = 11.3 months). Body mass index (BMI, kg/m2) was categorized as either below or above or equal to 30. Antihypertensive therapeutic intensity score (TIS) was calculated as the total daily antihypertensive dose/maximum United States Food and Drug Administration (USFDA) approved daily dose, summed across all hypertensive drugs. General linear models were used to estimate the significance of continuous variables across BMI categories. RESULTS: At baseline, systolic blood pressure (SBP) was similar between groups (P = 0.14), though 2.7 mm Hg higher in the highest BMI group. Antihypertensive TIS was greater in the highest BMI category at both baseline and end of follow-up (both P < 0.001). After covariate adjustment end of follow-up SBP and diastolic blood pressure was higher in the obese group by 3.4 (0.6-6.1) and 1.8 (0.1-3.53) mm Hg, respectively (P = 0.02, P = 0.04). CONCLUSIONS: Attained on-treatment BP is higher in obese than non-obese hypertensives despite greater prescription of antihypertensive medications. Whether even more prescription of medications or other interventions will equalize BP responses relative to non obese hypertensives merits further study.