Thiazide diuretics and the risk of osteoporotic fractures in hypertensive patients. Results from the Swedish Primary Care Cardiovascular Database

OBJECTIVE: The objective is to investigate if treatment with thiazides reduces the risk of osteoporotic fractures in hypertensive patients in primary healthcare. Further we aimed to examine the impact of duration of thiazide use, the consequences of discontinuation of treatment, and the possible difference in effect between men and women. METHOD: This retrospective cohort study includes 57 822 individuals, 45 years and older, diagnosed with hypertension during 2001-2008 in the Swedish Primary Care Cardiovascular Database. Patients were followed from 1 January 2006 (or the date of their first diagnosis of hypertension if that date came later), until they had an incident osteoporotic fracture, died, or reached the end of the study at 31 December 2012. Patients exposed to thiazides were compared with patients never exposed to thiazides. RESULTS: Current use of thiazides was associated with significantly reduced risk of osteoporotic fractures [hazards ratio 0.89; 95% confidence interval (CI) 0.81-0.98], and increased with longer treatment periods (hazards ratio 0.87; 95% CI 0.78-0.97 after 2 years). However, discontinuation of thiazides increased the risk of osteoporotic fractures (hazards ratio 1.18; 95% CI 1.04-1.33), but attenuated with longer duration past treatment period. When analyzing men and women separately, similar results were seen, although only significant in men. CONCLUSION: This large observational study confirms that thiazide therapy in hypertensive patients is associated with a reduced risk of osteoporotic fractures. The protective effect increased with longer treatment periods. However, discontinuation of treatment increased the risk of fractures, which emphasizes the importance of continuous treatment.