Infectious consequences of the AKI-to-CKD transition.

Background: Acute kidney injury (AKI) is associated with short- and long-term complications but the consequences of the AKI-to-CKD transition are still poorly understood. We aimed to evaluate the association between the AKI-to-CKD transition and the long-term risk of infection. Methods: This retrospective study included patients admitted in a tertiary hospital with community-acquired AKI in 2013 and 2014 who had their estimated glomerular filtration rate (eGFR) assessed at 3 months (±2 weeks) after serum creatinine peaked in the AKI episode. Key exclusion criteria were baseline CKD or confounding factors (active neoplasia, primary immunodeficiency, human immunodeficiency virus, immunosuppressive drugs). The association between the AKI-to-CKD transition (defined as an eGFR <60 ml/min/1.73 m2 at 3 months) and long-term infections (defined using clinical features, blood/urine analysis, cultures and imaging) was assessed during a follow-up of 9 months (range 2-56). Results: Among the 1731 patients admitted with AKI, 367 (21%) were included in the present analysis (64% male, 71 ± 15 years). Three months after AKI, 159 (43%) developed AKI-to-CKD transition. Baseline and post-AKI eGFR were independent predictors of AKI-to-CKD transition [hazard ratio (HR) 0.97, P = .044 and HR 0.96, P < .001, respectively].During follow-up, 153 (42%) patients developed an infection. Factors associated with infection were older age, cognitive impairment, lower post-AKI eGFR, eGFR loss from baseline to 3 months and AKI-to-CKD transition. Adjusted Cox regression showed that baseline eGFR, 3-month eGFR, eGFR loss and AKI-to-CKD transition were independent predictors of the long-term risk of infection. Conclusions: The AKI-to-CKD transition independently predicts the long-term risk of infection following an episode of AKI.