Background: Both COVID-19 infection and COVID-19 vaccines have been associated with the development of myopericarditis. The objective of this study is to (1) analyse the rates of myopericarditis after COVID-19 infection and COVID-19 vaccination in Hong Kong, (2) compared to the background rates, and (3) compare the rates of myopericarditis after COVID-19 vaccination to those reported in other countries. Methods: This was a population-based cohort study from Hong Kong, China. Patients with positive RT-PCR test for COVID-19 between 1st January 2020 and 30th June 2021 or individuals who received COVID-19 vaccination until 31st August were included. The main exposures were COVID-19 positivity or COVID-19 vaccination. The primary outcome was myopericarditis. Results: This study included 11,441 COVID-19 patients from Hong Kong, four of whom suffered from myopericarditis (rate per million: 326; 95% confidence interval [CI] 127–838). The rate was higher than the pre-COVID-19 background rate in 2019 (rate per million: 5.5, 95% CI 4.1–7.4) with a rate ratio of 55.0 (95% CI 21.4–141). Compared to the background rate, the rate of myopericarditis among vaccinated subjects in Hong Kong was similar (rate per million: 5.5; 95% CI 4.1–7.4) with a rate ratio of 0.93 (95% CI 0.69–1.26). The rates of myocarditis after vaccination in Hong Kong were comparable to those vaccinated in the United States, Israel, and the United Kingdom. Conclusions: COVID-19 infection was associated with significantly higher rate of myopericarditis compared to the vaccine-associated myopericarditis. Graphical

Introduction: The risk of new onset depression associated with sodium-glucose co-transporter 2 inhibitor (SGLT2I) use in patients with type 2 diabetes mellitus (T2DM) remains unclear. This study investigated the risk of new onset depression between SGLT2I and dipeptidyl peptidase 4 inhibitor (DPP4I) users. Methods: This was a population-based cohort study of T2DM patients in Hong Kong between January 1st, 2015, and December 31st, 2019. T2DM patients over 18 with either SGLT2I or DPP4I use were included. 1:1 propensity-score matching using the nearest-neighbour method was conducted based on demographics, past comorbidities and non-DPP4I/SGLT2I medication use. Cox regression analysis models were used to identify significant predictors for new onset depression. Results: The study cohort included a total of 18,309 SGLT2I users and 37,269 DPP4I users (55.57% male, mean age: 63.5 ± 12.9 years) with a median follow-up duration of 5.56 (IQR: 5.23–5.8) years. After propensity score matching, SGLT2I use was associated with a lower risk of new onset depression compared to DPP4I use (HR: 0.52, 95% CI: [0.35, 0.77], P = 0.0011). These findings were confirmed by Cox multivariable analysis and sensitive analyses. Conclusion: SGLT2I use is associated with significantly lower risk of depression compared to DPP4 use in T2DM patients using propensity score matching and Cox regression analyses.