Short-term studies have shown an attenuated immune response in hemodialysis patients after COVID-19-vaccination. The present study examines how antibody response is maintained after vaccination against SARS-CoV-2 in a large population of hemodialysis patients from six outpatient dialysis centers. We retrospectively assessed serum antibody levels against SARS-CoV-2 spike protein and nucleocapsid protein (electrochemiluminescence immunoassays, Roche Diagnostics) after COVID-19-vaccination in 298 hemodialysis and 103 non-dialysis patients (controls), comparing early and late antibody response. Compared to a non-dialysis cohort hemodialysis patients showed a favorable but profoundly lower early antibody response, which decreased substantially during follow-up measurement (median 6 months after vaccination). Significantly more hemodialysis patients had anti-SARS-CoV-2-S antibody titers below 100 U/mL (p < 0.001), which increased during follow-up from 23% to 45% but remained low in the control group (3% vs. 7%). In multivariate analysis, previous COVID-19 infections (p < 0.001) and female gender (p < 0.05) were significantly associated with higher early as well as late antibody vaccine response in hemodialysis patients, while there was a significant inverse correlation between patient age and systemic immunosuppression (p < 0.001). The early and late antibody responses were significantly higher in patients receiving vaccination after a SARS-CoV-2 infection compared to uninfected patients in both groups (p < 0.05). We also note that a higher titer after complete immunization positively affected late antibody response. The observation, that hemodialysis patients showed a significantly stronger decline of SARS-CoV-2 vaccination antibody titers within 6 months, compared to controls, supports the need for booster vaccinations to foster a stronger and more persistent antibody response.

No abstract

In their important cross-sectional study among patients with overt Cushing's syndrome, possible autonomous cortisol secretion and non-functioning adenomas Naka et al. [1] recently in this journal, that subclinical hypercortisolism was associated with overestimation of the glomerular filtration rate (eGFR) when calculated from serum creatinine (eGFRcre) in comparison to calculation from cystatin C (eGFRcys). The authors highlight the decrease in skeletal muscle mass as a possible attributing factor. Furthermore, they suggest that the dissociation between eGFRcre and eGFRcys could be used as a discriminating factor for subclinical hypercortisolism.Indeed, calculation of eGFR using serum creatinine is limited due to the association with muscle mass which is reduced in various diseases, with increasing age and as the authors present also among patients with Cushing's syndrome and even subclinical hypercortisolism. Therefore, cystatin C has been suggested as a better marker for estimation of the GFR due to independence of muscle mass. However, Naka et al. only briefly discuss a possible effect of corticosteroids on cystatin C levels. We would like to therefore emphasize recent studies concerning this matter in greater detail.Manetti et al. reported [2] a significant increase of cystatin C levels (0.79 mg/L vs. 1.06 mg/L) after intravenous application of methylprednisolone (15 mg/kg) among 23 patients with severe Graves' ophthalmopathy which