The impact of polypharmacy on 30-day COVID-related mortality in nursing home residents: a multicenter retrospective cohort study

PURPOSE: Both the coronavirus (COVID-19) disease and polypharmacy pose a serious threat to nursing home (NH) residents. This study aimed to assess the impact of polypharmacy on 30-day COVID-related mortality in NH residents with COVID-19. METHODS: Multicenter retrospective cohort study including NH residents from 15 NHs in the Netherlands. The impact of polypharmacy on 30-day COVID-related mortality was evaluated and assessed using multivariable logistic regression analyses with correction for age, sex, CCI, BMI and vaccination status. RESULTS: In total, 348 NH residents were included, with a mean age of 84 years (SD = 8); 65% were female, 70% lived in a psychogeriatric ward, with a main diagnosis of dementia. 30-day COVID-related mortality was 27.3%. We found a significant, positive association between the total number of medications and 30-day COVID-related mortality (OR 1.09; 95% CI 1.001–1.20, p = 0.046), after adjustment for age, sex, Charlson Comorbidity Index (CCI), Body Mass Index (BMI) and vaccination status. After additional correction for dementia (model 2) and use of PPI, vitamin D, antipsychotics and antithrombotics (model 3), this effect remained positive, but was no longer significant. CONCLUSION: Nursing home residents with a higher number of medications and who were not vaccinated, had a higher 30-day COVID-related mortality. These findings have important implications for the management of COVID-19 in the frail NH population. As such they underline the importance of deprescribing on the one hand, but also of improving vaccination rates on the other. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s41999-022-00723-4.