Benefits of strict adherence to an intensive structured care approach to blood pressure management in primary care within the intervention arm of a multicentre randomised controlled trial

Purpose: We sought the predictors and consequences of adherence to a structured care approach to the management of hypertension within the Valsartan Intensified Primary carE Reduction of Blood Pressure (VIPER-BP) Study. Methods: Prospective, multi-centre randomised controlled trial (119 primary care clinics and 2185 participants). Prospectively derived criteria for assessing adherence to the VIPER-BP intervention including treatment prescription and up-titration of therapy plus adherence to scheduled visits at 6, 10, 14 and 18weeks post randomization were applied to assess BP control within 26 weeks in 1085 intervention participants. Results: Mean age was 59.2±11.8 years, 61.7% were male and 66.7% had longstanding hypertension. Mean initial BP was 150±17/88±11mmHg with individual BP targets of ≤140/90mmHg, ≤130/80mmHg and ≤125/75mmHg in 29.3%, 53.7% and 17.1% participants, respectively. Adherence to the structured clinic visits ranged from 83 to 91% (59-86%±7 days). Overall, 27.1% had an adverse event. Minimum and maximal perprotocol adherence occurred in 19.3% and 26.0% participants respectively: with significantly (p < 0.001) lower BP levels (132±14/79±9mmHg vs. 141±15/83±11mmHg) and attainment of BP target (51.1% vs. 19.0%) in the latter group. Independent correlates (adjusted p < 0.05) of per-protocol adherence were the BP target, initial systolic BP, treatment group (mono- versus combination ARB therapy), race, type of clinic and presence of a practice nurse. Increasing per-protocol adherence was independently correlated with BP control (OR 1.41, 95% 1.27-1.58). Conclusions: Strict adherence to an intensive/ structured approach to hypertension management in primary care was associated with significantly improved BP control in the VIPER-BP Study intervention arm.