Evolving impact of the COVID-19 pandemic in chronic dialysis recipients over the course of pandemic waves and COVID-19 vaccination rollout: a French national study. (preprint)

BackgroundThis observational study aims to assess the impact of the pandemic on the evolving of kidney transplantations, survival, and vaccination in chronic dialysis recipients (CDR) over the COVID-19 pandemic subperiods. MethodsUsing the French national health claims database, incident persons with end stage kidney disease in years 2015 to 2021 treated with dialysis were followed-up until December 31, 2022. Kidney transplantion and survival over pandemic subperiods versus the prepandemic period were investigated using longitudinal models with time-dependent covariates. Moreover, the impact of cumulative doses of COVID-19 vaccine on hospitalization and survival were compared between CDR and matched-control individuals. FindingsFollow-up of the 71,583 CDR and 143,166 controls totalized 639,341 person-years (CDR: 184,909; controls: 454,432). The likelihood of receiving a kidney transplant decreased during all pandemic subperiods except one. Mortality in CDR increased during the 3 wave subperiods (hazard ratio (HR [95% confidence interval]): 1{middle dot}19 [1{middle dot}13-1{middle dot}27], 1{middle dot}19 [1{middle dot}15-1{middle dot}23], and 1{middle dot}12 [1{middle dot}07-1{middle dot}17], respectively). While vaccine coverage declined with each booster dose, receiving such doses was associated with lower risks of COVID-19-related hospitalization (0{middle dot}66 [0{middle dot}56-0{middle dot}77], 0{middle dot}83 [0{middle dot}72-0{middle dot}94] for 1st booster versus 2nd dose and 2nd booster versus 1st booster, respectively) and death (corresponding HR: 0{middle dot}55 [0{middle dot}51-0{middle dot}59], 0{middle dot}88 [0{middle dot}83-0{middle dot}95]). Evolving patterns in mortality and vaccination outcomes were similar in CDR and controls. InterpretationThe impact of the pandemic in CDR was not specific of the kidney disease per se. Study results also suggest future research aimed at increasing adherence to vaccine booster doses.

Direct and indirect impact of the COVID-19 pandemic on the survival of kidney transplant recipients: a national observational study in France. (preprint)

Background During the pandemic period, healthcare systems were substantially reorganized for managing COVID-19 cases. The corresponding changes on the standard care of persons with chronic diseases and the potential consequences on their outcomes remain insufficiently documented. This observational study investigates the direct and indirect impact of the pandemic period on the survival of kidney transplant recipients (KTR), in particular in those not hospitalized for COVID-19. Methods We conducted a cohort study using the French national health data system which contains all healthcare consumptions in France. Incident persons with end stage kidney disease between January 1, 2015 and December 31, 2020 who received a kidney transplant were included and followed-up from their transplantation date to December 31, 2021. The survival of KTR during the pre-pandemic and pandemic periods was investigated using Cox models with time-dependent covariates, including vaccination and hospitalization events. Findings There were 10,637 KTR included in the study, with 324 and 430 deaths observed during the pre-pandemic (15,115 person-years of follow-up) and pandemic periods (14,657 person-years of follow-up), including 127 deaths observed among the 659 persons with a COVID-19-related hospitalization. In multivariable analyses, the risk of death during the pandemic period was similar to that observed during the pre-pandemic period (hazard ratio (HR) [95% confidence interval]: 0.92 [0.77-1.11]), while COVID-19-related hospitalization was associated with an increased risk of death (HR: 10.62 [8.46-13.33]). In addition, pre-emptive kidney transplantation was associated with a lower risk of death (HR: 0.71 [0.56-0.89]), as well as a third vaccine dose (HR: 0.42 [0.30-0.57]), while age, diabetes and cardiovascular diseases were associated with higher risks of death. Interpretation Considering persons living with a kidney transplant with no severe COVID-19-related hospitalization, the pandemic period was not associated with a higher risk of death.

Vaccination and COVID-19 dynamics in hemodialysis patients: a population-based study in France. (preprint)

Abstract Importance: Maintenance hemodialysis (MHD) patients have a high mortality risk after COVID-19 and an altered humoral response to vaccines, but vaccine clinical efficacy remains unknown in this population. Objective: To estimate the association between vaccination and COVID-19 hospitalization rate in MHD patients Design: Using Bayesian multivariable spatiotemporal models, we estimated the expected number of SARS-CoV-2 severe infections (infections with hospital admission) in MHD patients from simultaneous cases in the general population. Setting: French population-based retrospective analysis in MHD and non-dialysis patients. Participants: Models were fitted from 3620 hospitalizations of MHD patients and 457,160 hospitalizations in the general population. Exposure: Severe SARS-CoV-2 infections in the general population and vaccine exposure. Main Outcome and Measure: Weekly incidence of severe infections in MHD patients. Results: During the first epidemic wave, incidence of severe infections in MHD patients was approximately proportional to incidence in the general population. However, our model overestimated incidence during the second wave, suggesting an effect of prevention measures during the 2nd wave. A second model (based on data up to the end of the 2nd wave) estimated that the risk in MHD patients decreased between waves 1 and 2, with incidence rate ratio (IRR) = 0.70 (95% CI: 0.64, 0.76). Moreover, while this model correctly estimated the reported MHD cases up to the end of the 2nd wave, predictions overestimated the expected number of cases from the beginning of the vaccination campaign. Using vaccination coverages as additional predictors permitted to correctly fit the weekly reported number of cases, with IRR in MHD patients of 0.41 (95% CI: 0.28, 0.58) for vaccine exposure in MHD patients and 0.50 (95% CI: 0.40, 0.61) per 10% increase in vaccination coverage in the same-age general population. Conclusions and Relevance: Our findings suggest that both individual and herd immunity due to vaccination may yield a protective effect against severe forms of COVID-19 in MHD patients.

Adult post COVID-19 multisystem inflammatory syndrome and thrombotic microangiopathy (preprint)

Background: The coronavirus disease 2019 pandemic has affected millions of people worldwide but medium and long-term consequences are unknown. Clinical series of Kawasaki-like multisystem inflammatory syndrome in children (MIS-C), occurring after SARS-Cov-2 spreading, have been recently described. Case presentation: We describe a case of post COVID-19 MIS in a 46-year-old man, with biopsy-proven renal thrombotic microangiopathy (TMA). Specific complement inhibition with Eculizumab was initiated promptly and lead to a dramatic improvement of renal function. Conclusion: Our case suggests that post COVID-19 MIS is not restricted to children and that TMA could play a central role in the pathophysiology of this syndrome