Blood pressure lowering medication initiation and fracture risk: a SWAN pharmacoepidemiology study

We examined the fracture risk after initiation of blood pressure-lowering drugs compared with initiation of antidepressants. Multivariable regression models demonstrated an increased risk of fracture among women initiating a blood pressure-lowering medication (HR 1.73, 95% CI 1.02-2.95). This is likely related to an increased risk of falls. Initiation of blood pressure-lowering drugs has been associated with fractures in several studies, presumably due to an increase in the risk of falls. However, these studies used self-controlled designs without active comparators. We examined the risk of fractures after initiation of blood pressure lowering drugs compared with initiation of antidepressants. Women participants in the Study of Women Across the Nation (SWAN) were potentially eligible if they initiated blood pressure-lowering or antidepressant drugs during follow-up. To reduce the risk of confounding, we estimated a propensity score that included potential confounders including age, menopausal status, osteoporosis, and osteoporosis medication use. The propensity score was used to match subjects in both groups and we then constructed multivariable logistic regression models comparing the risk of any fracture. Sensitivity analyses assessed a limited range of fractures less likely related to trauma. Among the 3302 potentially eligible women participating in the SWAN cohort, we were able to propensity-score match 289 women who initiated a blood pressure-lowering medication with 289 who initiated an antidepressant. Multivariable logistic regression models demonstrated an increased risk of fracture among women initiating a blood pressure lowering medication (OR 1.74, 95% CI 1.02-2.95). After excluding fractures of the digits and face, the results were similar (OR 1.57, 95% CI 0.88-2.81). There was evidence of an increased risk in fractures among women initiating blood pressure-lowering medications compared to those initiating antidepressants. This is likely related to an increased risk of falling.

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