Risk of falls associated with antihypertensive medication: population-based case-control study

Background: antihypertensive medications have long been implicated as a potential cause of falls in older people but, despite their widespread prescribing, the size of class-specific adverse effects remains unclear. Aim: to determine the role of antihypertensive medications in older people with a recorded fall in primary care. Design: case-control study. Setting: UK general practices contributing data to The Health Improvement Network primary care database. Methods: patients over 60 years of age with a first fall recorded between 2003 and 2006 were selected, and up to six controls per case matched by age, gender and general practice. We used conditional logistic regression to estimate odds ratios for ever exposure, and current/previous exposure to the main classes of antihypertensives, adjusting for co-morbidity. We also examined the effect of the time interval from first prescription to first fall. Results: amongst our 9,682 cases, we found an increased risk of current prescribing of thiazides (odds ratio (OR) 1.25; 95% confidence interval 1.15-1.36). At 3 weeks after first prescribing the risk remained 4.28 (1.19-15.42). We found a reduced risk for current prescribing of beta blockers (OR 0.90; 0.85-0.96). There was no significant association with current prescribing of any other class of antihypertensive. Conclusions: the study provides evidence that current prescribing of thiazides is associated with an increased risk of falling and that this is strongest in the 3 weeks following the first prescription.