Baseline moderate-range albuminuria is associated with protection against severe COVID-19 pneumonia

BACKGROUND: Diabetes mellitus is considered a leading contributor to severe coronavirus disease 2019 (COVID-19). AIM: To characterize differences between hospitalized diabetic patients with vs without COVID-19, and parameters associated with COVID-19 severity for prediction. METHODS: This case-control study included 209 patients with type 2 diabetic mellitus hospitalized at the Galilee Medical Center (Nahariya, Israel) and recruited between September 2020 and May 2021, 65 patients with COVID-19 infection in dedicated wards and 144 COVID-19-negative patients in internal medicine wards hospitalized due to other reasons. Clinical parameters - including age, type of antiglycemic medications, presence of retinopathy, smoking history, body mass index (BMI), glycosylated hemoglobin, maximum neutrophil:lymphocyte ratio (NLR(max)), C-reactive protein (CRP), estimated glomerular filtration rate (eGFR), and albumin (blood and urine) - were compared between the two primary patient groups, and then between COVID-19-negative patients hospitalized due to infectious vs non-infectious disease. Finally, we explored which parameters were associated with severe COVID-19 pneumonia. RESULTS: COVID-19-negative patients were older (63.9 ± 9.9 vs 59.8 ± 9.2, P = 0.005), and had longer duration of diabetes (P = 0.031), lower eGFR (P = 0.033), higher albumin (P = 0.026), lower CRP (P < 0.001), greater smoking prevalence (P < 0.001), and more baseline albuminuria (54.9% vs 30.8%, P = 0.005) at admission; 70% of COVID-19 patients with albuminuria had moderate-range albuminuria (albumin:creatinine 30-300 mg/g). Most of the patients with albuminuria had chronic kidney disease stage II (CKD II). Oral antiglycemic therapies were not significantly different between the two groups. Multivariable logistic regression showed that higher BMI was significantly associated with severe COVID-19 (OR 1.24, 95%CI: 1.01-1.53, P = 0.04), as was higher NLR(max) (OR 1.2, 95%CI: 1.06-1.37, P = 0.005). Surprisingly, pre-hospitalization albuminuria, mostly moderate-range, was associated with reduced risk (OR 0.09, 95%CI: 0.01-0.62, P = 0.015). Moderate-range albuminuria was not associated with bacterial infections. CONCLUSION: Moderate-range albuminuria in COVID-19-positive diabetic patients with CKD II is associated with less severe COVID-19. Further studies should explore this potential biomarker for risk of COVID-19-related deterioration and early interventions.