Proximal Tubular Dysfunction as a Predictor of Aki in Hospitalized Covid-19 Patients

ABSTRACT

Introduction: Severe acute respiratory syndrome coronavirus 2 associated pneumonia (COVID-19) is a modern pandemic. Recent evidence suggests that kidney is an important target organ in COVID-19. High concentration of Angiotensin converting enzyme receptors in the proximal tubules make them an early target. Proximal tubular dysfunction (PTD) may act as an early predictor of acute kidney injury (AKI), need for renal replacement therapy (RRT), intensive care unit (ICU) transfer, mechanical ventilation, hospital length of stay (LOS) and death. Method(s) This prospective observational study was conducted in the COVID unit, Bangabandhu Sheikh Mujib Medical University. 87 COVID-19 patients without preexisting kidney disease were screened for markers of PTD on admission. Patients having at least 2 of the 4 defining markers of PTD (inappropriate uricosuria, renal phosphate leak, normoglycemic glycosuria and proteinuria) positive on admission were considered to have PTD. 35 patients with PTD and 35 without PTD were followed up throughout their hospital stay and compared. Result(s) 52.9% of the patients had at least 2 of the 4 defining markers of PTD positive on admission. The most prevalent markers were proteinuria (66.7%), followed by hyperuricosuria (42.5%), renal phosphate leak (28.7%) and normoglycemic glycosuria (20.7%). Also, 67% patients had renal sodium leak and 32.2% patients had renal potassium leak. Mean age was 55.7 years. 50% of the patients were diabetic. The PTD group had significantly lower oxygen saturation and higher parenchymal involvement on HRCT chest, CRP and LDH compared to the non PTD group on admission. 32.9% patients developed AKI during their hospital stay. PTD group had higher odds of developing AKI (odds ratio 17.5 for stage 1, 24.8 for stage 2 and 25.5 for stage 3;p<0.0001). The mean duration of hospital stay was 9 days higher in the PTD group (p<0.001). PTD group also had higher odds of transferring to ICU (OR=9.4, p=0.002), need for mechanical ventilation (OR=10.1, p=0.002) and death (OR=10.3, p=0.001). There was complete recovery of PTD in 32.6% and complete renal recovery in 47.8% of patients during their hospital stay. 26.1% of the patients who developed AKI required hemodialysis. 11.4% of all patients died. Conclusion(s) Proximal tubular dysfunction is highly prevalent in COVID-19 patients very early in the disease and may act as a predictor of AKI, ICU transfer, need for mechanical ventilation and death. No conflict of interestCopyright © 2023