INTRODUCTION

Air pollution is a novel environmental risk factor for chronic kidney disease (CKD). Air quality improved during COVID-19 lockdowns; however, the effects of these lockdowns on PM concentrations and renal function remain unclear.

METHODS

We conducted a retrospective cohort study to compare air pollution and estimated glomerular filtration rate (eGFR) decline in patients with stage 5 CKD between a year-long period of lockdown (2020; n = 724) and a similar period before lockdown (2019, n = 758).

RESULTS

Compared with 2019, a 17.5% reduction in the average PM concentration (from 17.36% to 14.32%; < 0.001) and a 45.1% reduction (from 20.56% to 11.25%; < 0.001) in cumulative days with PM concentration >35 μg/m were noted in 2020. Moreover, a 93% reduction in PM air quality index >150 per station-day (from 0.43% to 0.03%) was observed in 2020. From 2019 to 2020, the yearly incidence of eGFR decline ≥5 mL/min/1.73 m decreased by 33.7% (24.6% vs 16.3%; < 0.001). Similarly, the proportion of patients who started undergoing regular dialysis also decreased by 32.7% in 2020 (from 20.8% to 14.0%; = 0.001).

CONCLUSION

Our findings suggest that fewer events of renal function decline during the COVID-19 pandemic may be associated with a decline in PM concentrations, supporting the global strategy of reducing air pollution to prevent CKD progression.