CKD increases risk of acute kidney injury during hospitalization

Hsu CY et al. (2008) The risk of acute renal failure in patients with chronic kidney disease. Kidney Int [doi:10.1038/ki.2008.107]

Chronic kidney disease (CKD) is a reputed risk factor for development of acute kidney injury (AKI) during hospitalization. This concept is based on studies in which baseline kidney function was estimated from serum creatinine concentration upon admission to hospital or intensive care unit; however, whether such serum creatinine levels reflect early-stage AKI or true baseline kidney function is unknown.

Hsu et al. compared prehospitalization estimated glomerular filtration rates (eGFRs; estimated by use of the abbreviated Modification of Diet in Renal Disease equation) of 1,764 adult members of the Kaiser Permanente Northern California health-care system who developed dialysis-requiring AKI during hospitalization with those of 600,820 individuals who did not.

Compared with a reference baseline eGFR of ≥60 ml/min/1.73 m², a baseline eGFR of 45–59 ml/min/1.73 m² was associated with an adjusted odds ratio of in-hospital AKI of 1.66 (95% CI 1.40–1.97). For eGFR values of 15–29 ml/min/1.73 m², the adjusted odds ratio for in-hospital AKI was 20.42 (95% CI 17.40–23.96). The presence of diabetes, hypertension, and proteinuria also increased the likelihood of developing in-hospital AKI, with adjusted odds ratios of 1.99 (95% CI 1.78–2.23), 1.55 (95% CI 1.37–1.76) and 2.84 (95% CI 2.52–3.19), respectively.

CKD is the main risk factor for AKI during hospitalization. In this study, the increased risk of AKI associated with even mildly reduced eGFR reinforces the validity of National Kidney Foundation guidelines, in which patients with an eGFR <60 ml/min/1.73 m² are classified as having CKD regardless of other factors.