Prognostic value of estimated glomerular filtration rate in hospitalised older patients (over 65) with COVID-19: a multicentre, European, observational cohort study

Abstract

Background The reduced renal function has prognostic significance in COVID-19 and it has been linked to mortality in the general population. Reduced renal function is prevalent in older age and thus we set out to better understand its effect on mortality. Methods Patient clinical and demographic data was taken from the COVID-19 in Older People (COPE) study during two periods (February–June 2020 and October 2020–March 2021, respectively). Kidney function on admission was measured using estimated glomerular filtration rate (eGFR). The primary outcomes were time to mortality and 28-day mortality. Secondary outcome was length of hospital stay. Data were analysed with multilevel Cox proportional hazards regression, and multilevel logistic regression and adjusted for individual patient clinical and demographic characteristics. Results One thousand eight hundred two patients (55.0% male; median [IQR] 80 [73–86] years) were included in the study. 28-day mortality was 42.3% (n = 742). 48% (n = 801) had evidence of renal impairment on admission. Using a time-to-event analysis, reduced renal function was associated with increased in-hospital mortality (compared to eGFR ≥ 60 [Stage 1&2]): eGFR 45–59 [Stage 3a] aHR = 1.26 (95%CI 1.02–1.55); eGFR 30–44 [Stage 3b] aHR = 1.41 (95%CI 1.14–1.73); eGFR 1–29 [Stage 4&5] aHR = 1.42 (95%CI 1.13–1.80). In the co-primary outcome of 28-day mortality, mortality was associated with: Stage 3a adjusted odds ratio (aOR) = 1.18 (95%CI 0.88–1.58), Stage 3b aOR = 1.40 (95%CI 1.03–1.89); and Stage 4&5 aOR = 1.65 (95%CI 1.16–2.35). Conclusion eGFR on admission is a good independent predictor of mortality in hospitalised older patients with COVID-19 population. We found evidence of a dose-response between reduced renal function and increased mortality.

The prognostic value of estimated glomerular filtration rate on admission for death within 30 days among COVID-19 inpatients using fractional polynomial and spline smoothing

“…In a study in England [ 14 ], compared with eGFR of 90, the relative risks for G2–G5 categories were 1.17, 2.07, 2.46, 3.71, and 8.35, respectively among people with type 1 diabetes with COVID-19 and 1.02, 1.39, 1.76, 2.31, and 4.91, respectively among people with type 2 diabetes with COVID-19. In another study that included patients aged 65 years or older [ 13 ], compared with eGFR of 60, the ORs of mortality for eGFR of 1–29, 30–44, and 45–69 were 1.42, 1.41, and 1.26, respectively. The effect measures in our study were in line with the two former studies [ 13 , 14 ] in direction but different in magnitude.…”

“…In another study that included patients aged 65 years or older [ 13 ], compared with eGFR of 60, the ORs of mortality for eGFR of 1–29, 30–44, and 45–69 were 1.42, 1.41, and 1.26, respectively. The effect measures in our study were in line with the two former studies [ 13 , 14 ] in direction but different in magnitude. The OR for patients in the G5 category in our study was 15.14 based on the FP model.…”

“…Several studies also showed the prognostic value of eGFR for adverse outcomes, such as mortality and ICU admission, in COVID-19 patients [ 11 , 12 ]. In previous studies, eGFR was included in prediction models in continuous and categorical forms, and a linear relationship is assumed between eGFR and mortality [ 13 , 14 ]. However, in some scenarios, the relationship between a continuous covariate e.g., eGFR and mortality may be non-linear, such as J -shaped or U -shaped.…”

Early reduction of estimated Glomerular Filtration Rate (eGFR) predicts poor outcome in acutely ill hospitalized COVID-19 patients firstly admitted to medical regular wards (eGFR-COV19 study)

“…A recent study, aiming at finding biomarkers able to stratify acutely ill COVID-19 patients requiring sub-intensive/intensive care in order to prevent poor outcome, retrospectively evaluated a small sample size (231 patients) and pinpointed to eGFR value at hospital admission as good predictor of high risk for clinical deterioration and in-hospital death [34] . The other study intentionally considered hospitalized elderly COVID-19 patients aged ≥ 65 years [35] , whereas our study considers hospitalized COVID-19 patients aged ≥ 18 years, so that our study population is much more inclusive.…”

The Effect of Estimated Glomerular Filtration Rate on Mortality in the Elderly COVID-19 Patients in the Intensive Care Unit

“…[4] It has been defined as the sign of mortality in COVID-19 patients and non-COVID-19 patients who had both acute and chronic kidney disease (CKD). [5] Kidney failure represents a para-physiological case secondary to aging with an annual decrease of approximately 1 mL/ min in GFR. Additionally, metabolic comorbidities such as diabetes mellitus and hypertension negatively affect renal function and cause a more rapid decrease in GFR.…”