AB022. Angiotensin receptor blocker (ARB) versus angiotensin-converting enzyme inhibitor (ACE-I) use for new-onset pneumonia and lung infections: a propensity score-matched population-based cohort study with competing risk analyses

Background: The effects of angiotensin receptor blockers (ARB) and angiotensin-converting enzyme inhibitors (ACE-I) on new-onset respiratory tract infections remain unclear. This study aimed to compare the risks of pneumonia and lung infections between ARB and ACE-I users. Methods: This retrospective cohort study included patients who were prescribed ARB/ACE-I in Hong Kong between 1st January 2000 and 31st August 2020. The primary outcomes were new-onset pneumonia and new-onset bacterial, viral, and influenza lung infections. The secondary outcomes were pneumonia, cardiovascular, and all-cause mortality. Patients <18 years old or with prior diagnoses of the above events were excluded. A one-year lag time since initial ARB/ACE-I use was introduced to account for the latency of outcomes and reverse causality. 1:1 propensity score matching was performed based on demographics, prior comorbidities, use of other medications, and laboratory tests. Results: After 1:1 propensity score matching, the study cohort consisted of 54,436 ARB users (45.9% male, mean age: 69.3±13.6 years, median follow-up time: 4.8 years [interquartile range (IQR): 3.1–7.8)] and 54,436 matched ACE-I users [54.0% male, mean age: 68.3±13.6 years, median follow-up time: 7.6 years (IQR: 4.3–13.5)]. ARB use was associated with higher risks of pneumonia [hazard ratio (HR): 5.73, 95% confidence interval (CI): 4.49–7.32, P<0.0001], bacterial lung infection (HR: 4.17, 95% CI: 2.94–5.91, P<0.0001), viral lung infection (HR: 4.02, 95% CI: 1.83–8.83, P=0.0005), influenza lung infection (HR: 9.84, 95% CI: 6.61–14.63, P<0.0001), pneumonia mortality (HR: 2.86. 95% CI: 2.78–2.95, P<0.0001), cardiovascular mortality (HR: 2.36, 95% CI: 2.30–2.42, P<0.0001), and all-cause mortality (HR: 1.82, 95% CI: 2.30–2.42, P<0.0001) than ACE-I use. These associations remained significant across follow-up times since initial ARB/ACE-I use. However, in the first three years, there were no significant differences in the risks of bacterial and viral lung infections, and mortality between ARB and ACE-I users. The results were confirmed by sensitivity analyses with cause-specific hazard models and sub-distribution hazard models. Conclusions: The use of ARB was associated with higher risks of pneumonia, lung infections, and mortality than ACE-I use. The decision whether to prescribe ARB or ACE-I for short-term treatment should be made by weighing pneumonia and mortality risks.