Cardiovascular outcome in treatment-resistant hypertension: results from the Swedish Primary Care Cardiovascular Database (SPCCD)

Objective: To assess cardiovascular outcome in patients with treatment-resistant hypertension (TRH) compared with patients with nontreatment-resistant hypertension (HTN). Methods: Cohort study with data from 2006 to 2012 derived from the Swedish Primary Care Cardiovascular Database with hypertensive patients aged at least 30 years. TRH was defined as blood pressure at least 140/90mmHg despite medication adherence to three or more dispensed antihypertensive drug classes. Patients with cardiovascular comorbidity were excluded. The association between TRH and cardiovascular events with adjustment for important confounders was analyzed. Results: We included 4317 TRH patients and 32 282 HTN patients. TRH patients (61% women) were older (70 vs. 66 years), had higher SBP (152 vs. 141 mmHg) and more diabetes (30 vs. 20%) (P<0.001 for all) compared with HTN patients. Mean follow-up time was 4.3 years. In the adjusted analysis, TRH patients had an increased risk for total mortality [hazard ratio 1.12; 95% confidence interval (CI), 1.03-1.23], cardiovascular mortality (hazard ratio 1.20; 95% CI, 1.03-1.40) and incident heart failure (hazard ratio 1.34; 95% CI, 1.17-1.54) but not for incident stroke (hazard ratio 1.03; 95% CI, 0.90-1.19) or transitoric ischemic attack (hazard ratio 1.12; 95% CI, 0.86-1.46) compared with HTN patients. Conclusion: Patients with TRH have a poor prognosis beyond blood pressure level, compared with hypertensive patients without TRH. In particular, the high risk for heart failure is of clinical importance and merits further investigation.