Serum cystatin C as an early marker of Acute Kidney Injury in elderly patients after surgery for femur fracture. An observational study

José de Souza Andrade Neto, MD, PhD, Vera Lucia Fernandes de Azevedo, MD, PhD, Italo Lopes and Carvalho, MD, Reinaldo da Silva Santos Junior, MD, MsC, Paulo do Nascimento Junior, MD, PhD and Norma Sueli Pinheiro Modolo, MD, PhD

Background: Acute kidney injury (AKI) is prevalent in hospitalized patients, primarily in patients undergoing major surgical procedures. AKI is associated with increased morbimortality, and patients would benefit from a very early diagnosis that would allow implementation of specific therapeutic or additional prophylactic measures. The present study evaluated serum cystatin C as an early predictor of AKI in elderly patients during the postoperative period.

Methods: Fifty-nine patients, aged 60 years or older undergoing correction of femur fracture under spinal anaesthesia, were prospectively evaluated up to 48 hours after surgery. Serum cystatin C was measured immediately after surgery and four (early marker) and 24 hours after surgery. The diagnosis of AKI was based on creatinine values up to 48 hours after surgery (Kidney Disease Improving Global Outcomes, KDIGO), and the impact of serum cystatin C on the diagnosis of AKI was evaluated four hours after surgery.

Results: Twenty-one patients (35.6%) were diagnosed with AKI. The values of serum cystatin C [median (1st - 3rd quartiles)] at four hours were 1.24 (1.00 - 1.49) and 0.90 (0.78 - 1.15) mg.L-1 for patients with and without AKI, respectively (p = 0.003). The best serum cystatin C cut-off value at four hours was 0.92 mg.L-1, with negative and positive predictive values equal to 95% and 50%, respectively, a sensitivity of 94%, a specificity of 51%, and an accuracy (area under the curve) of 75% (95% confidence interval: 61% to 86%).

Conclusions: Serum cystatin C exhibited good accuracy (75%) for the diagnosis of AKI and elevated the potential identification of patients with lower chances of presenting AKI at a cut-off value of 0.92 mg. L-1 four hours after femur fracture repair under spinal anaesthesia.

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Published on: May 6, 2019 Pages: 1-7

Full Text PDF Full Text HTML DOI: 10.17352/2455-5495.000031
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