Predictors of acute kidney injury in geriatric patients undergoing total knee replacement surgery

Few studies have focused on patients' characteristics that affects acute kidney injury (AKI) after total knee replacement surgery (TKR).

The primary objective of this retrospective study was to identify patients' characteristics associated with AKI after TKR.

Between January 2008 and December 2009, 659 patients with a mean age of 67.1 years (range, 39-99) underwent TKA at Regional Hospital Knee and Hip Institute. Retrospective chart review was done to identify patients' characteristics that were associated with AKI after TKR. Logistic regression was used to evaluate AKI.

AKI occurred in 21.9% of patients. AKI risk decreased between 2008 and 2009 (odds ratio, 0.55; 95% CI, -0.37 to 0.82) but increased with age (P < 0.001), diabetes mellitus (DM), and angiotensin converting enzyme inhibitors (ACEI)/angiotensin receptor blockers (ARB) use (OR, -1.6; 95% CI, -1.0 to 2.5; and OR, -1.5, 95% CI, -1.0 to 2.3, respectively). However, the effects of DM and ACEI/ARB use were not independent; when both were included in the regression model, neither was statistically significant, and both ORs were smaller than combined OR.

When examined separately, both DM and preoperative ACEI/ARB use increased the risk of AKI; however these factors were correlated and were not independent predictors of significantly increased risk. Patients with DM have higher tendency to develop AKI and hence, preoperative renal risk stratification should be done in all patients with DM.