Indirect effect of the COVID-19 pandemic on mortality, complications, and healthcare utilization among people with Chronic Kidney Disease in Hong Kong: an interrupted time series analysis

Background:
Evidence on health outcomes and healthcare use in chronic kidney disease (CKD) patients without COVID-19 is scarce.

Methods:
We applied an interrupted time series analysis on population-based data in Hong Kong, analyzing individuals first diagnosed with CKD from January 2010 to April 2022. We evaluated changes in all-cause mortality, kidney failure, cardiovascular diseases (CVD), and healthcare utilization across four periods: pre-pandemic (January 2012-January 2020), early pandemic (February 2020–January 2021), interwave (February 2021–December 2021), and Omicron (January 2022–April 2022). Seasonality-adjusted Quasi-Poisson regression models and subgroup analyses by age, sex, Charlson Comorbidity Index, and CKD stage were conducted.

Results:
All-cause mortality increased significantly by Incidence rate ratio (IRR) ((95% confidence interval (CI)): 1.012 (1.006–1.018)) during the interwave period. The incidence of kidney failure (IRR (95% CI): 0.850 (0.782–0.923)) and CVD decreased (IRR (95% CI): 0.867 (0.769–0.978)) during the early pandemic period. During the interwave period, CVD incidence increased (IRR (95% CI): 1.155 (1.084–1.231)), while kidney failure incidence did not. Subgroup analysis indicated reduced healthcare use and increased mortality rates in CKD Stage 3– 4 patients during the early pandemic and interwave periods, respectively.

Conclusion:
There were delayed diagnoses of CVD and an increase in mortality rate among CKD patients without COVID-19 after the first wave in Hong Kong. The increased mortality may have resulted from reduced healthcare utilization and delayed access to care among these high-risk patients. This study underscores the need for contingency plans to continue following-up and monitoring patients with CKD (eg teleconsultation) during future public health crises.)