Changes in the Use of Hydrochlorothiazide and Other Antihypertensive Drugs in Switzerland in Association With the Swissmedic Safety Alert Regarding Non-melanoma Skin Cancer: An Interrupted Time-Series Analysis Using Swiss Claims Data.

Purpose: Long-term use of hydrochlorothiazide increases the risk of non-melanoma skin cancer. We aimed to evaluate potential changes in the use of hydrochlorothiazide in Switzerland after a direct healthcare professional communication (DHPC) in November 2018 by Swissmedic.
Methods: We performed interrupted time-series analyses using a large Swiss healthcare claims database (2015-2021). Within monthly intervals, we quantified the total number of claims and the total dispensed 'defined daily doses' (DDD) for preparations containing (1) hydrochlorothiazide, (2) angiotensin-converting enzyme (ACE) inhibitors and angiotensin-II-receptor blockers (ARB), (3) calcium-channel blockers (CCB) and (4) thiazide-like diuretics per 10 000 persons. Using segmented linear regression, we quantified the pre-DHPC trend, the immediate change and the post-DHPC change in trend for total claims and DDD for the four drug classes weighted for the demographic distribution of the Swiss population.
Results: ACE inhibitors and ARB were the most frequently claimed antihypertensive drugs with 300-400 claims per 10 000 persons, which increased by 5.4% during the study period. The average number of hydrochlorothiazide claims (157/10 000 persons in 2015) declined by 35% between 2015 and 2021. The decrease started prior to the DHPC, but the DHPC was associated with an immediate 6.1% decline and an accelerated decline in claims over time after the DHPC (similar results for DDD). This coincided with a 23% increase in claims of CCB (dihydropyridine type) over 7 years, whereas use of other antihypertensives increased less.
Conclusion: Our results suggest that the DHPC by Swissmedic in 2018 accelerated a pre-existing decline in the use of hydrochlorothiazide in Switzerland.
(© 2024 The Author(s). Pharmacoepidemiology and Drug Safety published by John Wiley & Sons Ltd.)