Preoperative dipstick albuminuria and other urine abnormalities predict acute kidney injury and patient outcomes

Abstract

BACKGROUND:

It is unclear whether pathologic findings on preoperative urinalysis are associated with the risk of postoperative acute kidney injury (AKI). Therefore, we performed a retrospective review to investigate this association.

METHODS:

We assessed the clinical significance of preoperative dipstick urinalysis in a 10-year surgery cohort from a tertiary hospital in Korea. Patients without available information on perioperative serum creatinine levels or kidney injury prior to surgery were excluded. Preoperative dipstick urinalysis parameters, including albuminuria, hematuria, pyuria, and others were studied. The primary outcome was postoperative acute kidney injury. Secondary outcomes were postoperative 1-year mortality and progression of poor kidney function parameters.

RESULTS:

We enrolled 40,090 patients. The presence of dipstick albuminuria was associated with an increased risk of postoperative AKI (adjusted odds ratio 1.47 [1.29-1.66], P < .001), and the association showed a dose-response relationship. High specific gravity was significantly associated with increased risk of AKI (adjusted odds ratio 1.30 [1.04-1.63], P = .02). Furthermore, in patients with postoperative AKI, those with baseline albuminuria had a worse prognosis with regard to 1-year mortality (adjusted hazard ratio 2.81 [1.56-5.09], P < .001) and persistent renal function impairment (adjusted odds ratio 2.07 [1.21-3.46], P = .007), independent of estimated glomerular filtration rate values. Patients with baseline hematuria and pyuria also had an inferior postoperative AKI prognosis when compared to those without the urinalysis abnormalities.

CONCLUSION:

Baseline dipstick urinalysis may predict postoperative AKI and may be significantly associated with prognosis after surgery.