Impact of COVID-19 pandemic on mortality rate in memory clinic patients

INTRODUCTION: We investigated whether mortality in memory clinic patients changed due to coronavirus disease 2019 (COVID-19) pandemic. METHODS: We included patients from the Amsterdam Dementia Cohort: (1) n = 923 pandemic patients (baseline visit: 2017–2018, follow-up: until 2021), and (2) n = 830 historical control patients (baseline visit: 2015–2016, follow-up: until 2019). Groups were well-balanced. We compared mortality during pandemic with historical control patients using Cox regression. Differences in cause of death between groups were explored using Fisher's exact test. RESULTS: Pandemic patients had a higher risk of mortality than historical control patients (hazard ratio [HR] [95% confidence interval {CI}] = 1.34 [1.05–1.70]). Stratified for syndrome diagnosis, the effect remained significant in dementia patients (HR [95% CI] = 1.35 [1.03–1.78]). Excluding patients who died of COVID-19-infection, the higher mortality risk in pandemic patients attenuated (HR [95% CI] = 1.24 [0.97–1.58]). Only the difference in cause of death between pandemic patients and historical control patients for death to COVID-19-infection (p = 0.001) was observed. CONCLUSION: Memory clinic patients had increased mortality risk during COVID-19 compared to historical control patients, attributable to dementia patients. Highlights: We investigated if mortality rates in memory clinic patients changed due to COVID-19 pandemic. We included patients along the cognitive continuum, including SCD, MCI, and dementia. We used a well-balanced historical control group. Memory clinic patients had higher risk for mortality during COVID-19 lockdown. Our results indicate that excess mortality is mainly caused by death to COVID-19 infection.