Acute kidney injury is an independent predictor of in-hospital mortality in a general medical ward: A retrospective study from a tertiary care centre in south India

BACKGROUND & OBJECTIVES: Acute kidney injury (AKI) has been identified as an independent risk factor for mortality in intensive care units. This retrospective study was conducted to determine the effect of AKI on in-hospital mortality in a general medical ward of a tertiary care hospital and risk factors for mortality in patients with AKI. METHODS: Demographic and clinical details, and outcome data were collected from case records of patients. In all hospitalized patients, factors associated with increased in-hospital mortality, such as AKI, inotrope requirement, mechanical ventilation and primary disease were compared between patients who died during their hospital stay and those who were discharged alive. Among the hospitalized patients, who had AKI, likely predictors of in-hospital mortality were compared between dead and alive patients at discharge. Factors that were significant in univariate analysis were tested by multivariate regression analysis to identify those that independently predicted poor outcomes. RESULTS: Of the 1150 patients admitted in a general medical ward in a year, 220 patients were identified to have AKI. In-hospital mortality rate among patients with AKI was 19.09 per cent as compared to 1.8 per cent without AKI [adjusted odds ratio (OR) 5.7 (95% CI: 1.56-20.74)]. The presence of AKI was an independent risk factor for death, with an adjusted OR of 6.0 [95% CI: 1.67-21.6]. Among patients with AKI, the presence of haematological malignancy, adjusted OR 25.86 (95% CI: 1.81-369.58), requirement of inotrope, adjusted OR 126.5 (95% CI: 19.39-825.93) and serum creatinine at admission (P<0.001) were found to be independent predictors of death. The presence of underlying chronic kidney disease and hospital-acquired AKI were not found to have an association with mortality. INTERPRETATION & CONCLUSIONS: The study showed the in-hospital mortality rate among patients with AKI in a general medical ward was 19.09 per cent. The occurrence of AKI was an independent risk factor for death, with haematological malignancy, use of vasopressors and higher serum creatinine at admission, significantly associated with death among patients with AKI. Large prospective studies need to be done to better understand the outcomes in AKI and the ways to present and manage AKI.