OBJECTIVES: A national French cohort study was devised for investigating the impact of the pandemic waves and between-wave sub-periods on the survival of chronic dialysis recipients (CDR). The association between vaccination roll-out and mortality was also investigated.

METHODS: Using the French national health claims database, incident persons with end stage kidney disease between 2015 and 2020, except those who received a pre-emptive kidney transplant were included and followed-up from their first dialysis date to December 31, 2022. The survival of CDR during the pre-pandemic and pandemic periods were estimated and compared to controls (matched on sex, age, comorbidities and region), using Cox models with time-dependent covariates.

RESULTS: The 60,481 CDR and 120,962 matched controls totalized 600,175 person-years followed-up. Global mortality in CDR was higher than in controls (hazard ratio (HR) [95% confidence interval]: 3.12 [3.06-3.18]). Compared to the pre-pandemic period, the pandemic first (March 01 to May 18, 2020) and second wave (September 07, 2020 to May 10, 2021) sub-periods were associated with a higher risk of death (HR 1.18 [1.13-1.24], 1.10 [1.07-1.13], respectively), while the risk of death was similar during the third wave (November 21, 2021 to April 25, 2022, HR: 0.97 [0.93-1.02). In contrast, the first, second and third between-wave sub-periods were associated with a lower risk of death (HR: 0.88 [0.84-0.91], 0.87 [0.84-0.90] and 0.81[0.78-0.84] respectively). Sub-period evolving trends were similar in CDR and controls. Adherence to COVID-19 vaccine booster was low, although increasing doses were associated with decreasing risks of death (HR: 0.68 [0.66-0.69] to 0.35 [0.30-0.41] for 2 to 5 doses, respectively).

CONCLUSIONS: During the pandemic period in France, excess mortality in CDR decreased with time, and likely characterized with a between-wave-related harvesting pattern similar in CDR and controls. The study advocates research on candidate policies for increasing adherence to vaccine booster doses.