PhD Student The University of Hong Kong Hong Kong, Hong Kong
Background: Ageing is one of the major global public health concerns as it increases the risk of neurodegenerative diseases, largely represented by dementia. Hypertension in the mid to late-life is also associated with an increased risk of incident dementia and whether the use of different classes of antihypertensive drugs affects the incidence of dementia is unclear.
Objectives: The study aims to compare the incidence of dementia in patients exposed to different classes of blood pressure-lowering drugs (BPLD).
Methods: This is a population-based cohort study using electronic health data from the Hong Kong (HK) Hospital Authority and the IQVIA Medical Research Database in the United Kingdom (UK). The target population were those aged 40 years or older and who were new users of BPLD. Individuals required two consecutive prescriptions of the same class of BPLD and were followed up from initiation until the earliest of outcome, death or last observation. The primary outcome was all-cause dementia with secondary outcomes of dementia subtypes. Patients were put into comparison groups based on the BPLD class initiated, with ACE inhibitors as the reference comparison group. Patients were classified into the combination group if they were initiated with two or more classes of BPLD. Inverse probability of treatment weighting (IPTW) was used to balance baseline characteristics between groups and adjusted Cox proportional hazards models with IPTW were used to generate hazard ratios (HRs).
Results: The study included 729,898 new users of BPLD in Hong Kong 762,034 in the United Kingdom. The mean age at initiation for all individuals was 63 and 64 years old in HK and UK, respectively, (Standard Deviation: 12 for both sites) and the median follow-up was 8.6 and 7.4 years, respectively. In HK, there was a lower incidence of all-cause dementia in the beta-blocker group (HR: 0.91, 95% CI: 0.87-0.96) and combination group (HR: 0.87, 95% CI: 0.82-0.91) when compared with the ACE inhibitor group. In UK, there was a lower incidence in the beta-blocker group (HR: 0.93, 95% CI: 0.89-0.97) and angiotensin-II receptor blocker group (HR: 0.91, 95% CI: 0.86-0.97). There was no difference for other BPLD classes without a lower incidence. Similar results were found when breaking down the outcome into dementia subtypes.
Conclusions: This study showed that among all BPLD classes, initiation with beta-blockers in HK and UK was associated with a lower risk of incident dementia when compared to initiation with ACE inhibitors. The lower risk was also found in initiation of two or more classes of BPLD in HK and angiotensin-II receptor blockers in UK. The results can inform decision-making when prescribers are faced with a choice of antihypertensives. Studies in more countries are warranted to further support these findings.
