Temporal trends of first time antihypertensive treatment among citizens over 75 years - a register-based, cohort study

Abstract

Abstract Background Hypertension is highly prevalent, particularly among the increasingly large elderly population. There is a need for investigating the use of antihypertensive drugs in elderly patients. Data on clinicians’ first drug of choice, effectiveness, and magnitude of use are sparse, partly due to older patients often being excluded from clinical trials which in turn limits knowledge about their cardiovascular drug safety. Furthermore, drug metabolism and pharmacokinetics are known to differ with increasing age. Purpose To investigate temporal trends for first-line drug choice for first time antihypertensive treatment among elderly patients over 75 years from 2000-2021. Methods Using nationwide registers, we identified all patients over 75 years initiated on either beta blockers (BB), calcium channel blockers (CCB), renin-angiotensin system inhibitors (RASi), thiazides, or a combination between 2000-2021. Patients treated earlier in life with any antihypertensive drug were excluded, as were patients with atrial fibrillation, heart failure, chronic kidney disease, and acute coronary syndrome. Patients were included on the date of their first claimed prescription and temporal trends were reported as proportions per calendar year. We described adherence, change or discontinuation of antihypertensive medication using additionally claimed prescriptions during the first 180 days following study entry. Only patients alive 180 days after initial inclusion contributed to the latter analysis. Results A total of 187,309 patients (median age 80 years [interquartile range (IQR) :77-84], 59.1% female) were eligible for inclusion. The first drug of choice for antihypertensive treatment in patients above 75 years of age has changed markedly between 2000 (BB 12.7%, CCB 22.3%, RASi 11.6%, thiazides 61.3%, and combinations 2.6%) and 2021 (BB 12.9% CCB 28.2%, RASi 48.2%, thiazides 8.0%, and combinations 2.7%), especially for RASi and thiazides (Figure 1). Following the first 180 days, 172,756 patients (median age 80 [IQR:77:84], 59.3% female) were still alive and eligible. Adherence, discontinuation, and shift varied according to first drug of choice. Discontinuation within 180 days was highest among patients initiated on thiazides 19,544 (28.4%) whereas most patients continued the same 1-drug regimen if they started on RASi (64.6%), BB (57.8%), and CCB (59.5%). The highest proportion who had a second drug added within 180 days were patients initiated on CCB (21.1%) and RASi (21.1%) (Figure 2). Conclusion Elderly patients initiated on antihypertensive medication for the first time after the age of 75 is a substantial patient group, and from 2000–2021 a preference for thiazides has largely been replaced by RASi and CCB. It seemed that patients initiated on thiazides were more likely to discontinue or shift shortly afterwards. Further evaluation of thiazides as an equal first drug of choice for hypertension in the elderly could be warranted.