Relation between insufficient response to antihypertensive treatment and poor compliance with treatment: a prospective case-control study

OBJECTIVES: To prospectively compare compliance with treatment in patients with hypertension responsive to treatment versus patients with treatment resistant hypertension. DESIGN: Prospective case-control study. SETTING: Outpatient department in a large city hospital in Switzerland, providing primary, secondary, and tertiary care. PARTICIPANTS: 110 consecutive medical outpatients with hypertension and taking stable treatment with at least two antihypertensive drugs for at least four weeks. MAIN OUTCOME MEASURES: Treatment compliance assessed with MEMS devices; blood pressure determined by 12 hour daytime ambulatory monitoring (pressure <135/85 mm Hg in patients aged ⩽60 years and <155/90 mm Hg in patients aged >60 indicated hypertension responsive to treatment). RESULTS: Complete data were available for 103 patients, of whom 86 took ⩾80% of their prescribed doses (“compliant”) and 17 took <80% (“non-compliant”). Of the 49 patients with treatment resistant hypertension, 40 (82%) were compliant, while 46 (85%) of the 54 patients responsive to treatment were compliant. CONCLUSION: Non-compliance with treatment was not more prevalent in patients with treatment resistant hypertension than in treatment responsive patients.