β1 selectivity of β-blockers and reduced risk of fractures in elderly hypertension patients

Introduction: Hypertension and osteoporosis are prevalent in the elderly population. Treatments beneficial to both conditions would be helpful. We examined the protective effect of β-blockers (BBs) and their receptor selectivity against fractures compared to other antihypertensives. Materials and methods: A retrospective cohort was assembled using the Korean Health Insurance Review and Assessment Service database from January 2005 to June 2006. The cohort consisted of 501,924 patients (ages 65 and older) on single-drug therapy for hypertension. Participants were followed to either the date of the first fracture, date of death or end of the study period (30 June 2006), whichever came first. Cox's proportional hazard model was used to calculate the adjusted hazard ratio (aHR) and 95% confidence interval (CI) by sex, adjusting for confounders. Risk of fractures by BBs according to β1 selectivity was compared to non BBs measured in aHR. Results: Among 501,924 (65% female), the incidence density of fractures in non BB users was 29.3 and 48.2 per 1000 person-years for men and women, respectively, which was higher than in BB users (17.2 for men and 30.5 for women). Compared to BB users, non BB users showed an increased risk of all fracture [aHR 1.56 (95% CI, 1.42-1.72) in men and 1.44 (95% CI, 1.36-1.51) in women] and hip fracture [aHR 2.17 (95% CI 1.45-3.24) in men and 1.61 (95% CI 1.31-1.98) in women] after adjusting for confounding variables. Compared to BBs, the risks of all fractures in α-blockers, calcium channel blockers, diuretics, and renin-angiotensin-aldosterone system blockers were significantly higher (1.72, 1.77, 1.58, 1.29 in men; 2.11, 1.50, 1.46, 1.22 in women, respectively). Compared to non BBs, β1 selective BBs showed a lower risk of fracture (39% for men and 33% for women) after adjusting for confounding factors. On the contrary, non-selective BBs were not protective against fracture. Conclusion: Our results suggested that β1 selective BBs reduce the risk of fractures compared to other classes of antihypertensives in an elderly population, which could have practical applications for strategies to control and prevent adverse outcomes from both hypertension and osteoporosis in this population.