1009

Abstract

Introduction: Severe Sepsis (SS) and acute kidney injury (AKI) are costly postoperative complications that frequently occur together. Cost burden of SS has been extensively studied; the increased cost of concurrent SS and AKI less so. Methods: This was a retrospective cohort study of 50,314 adult patients with previously normal renal function undergoing surgical procedures requiring > 48 hours admission. SS was defined using the Agency for Healthcare Research and Quality (AHRQ) patient safety indicators "Postoperative Sepsis". Risk, Injury, Failure, Loss, and End-stage Kidney (RIFLE) consensus criteria and serial serum creatinine measurements were used to define AKI. We modeled the primary outcome variable, inflation adjusted hospital cost, as a function of common postoperative complications. All models were adjusted for hospital stay characteristics and validated using validation datasets. Adjusted costs for patients with and without each postoperative complication and 95% confidence intervals were calculated for each. Hospital cost was log transformed due to skewness. Smearing estimates were used to correct for bias when estimates were back-transformed. Results: Average cost per patient with no complications was $15,600 (95%CI: $15,500-$15,700). AKI occurred in 35% of patients with average cost per patient of $24,300 (95%CI: $23,900, 24,600); SS 4.8% with average cost per patient of $31,200 (95%CI: $24,700, $37,700). 94% of patients with SS had concurrent AKI with average cost per patient of $54,500 (95%CI: $43,600-$65,400). Additional postoperative complications occurred more frequently in patients with AKI and SS; each with an average cost increase of 8 to 9 times that of patients without AKI and SS. The most common and costly were ICU admission greater than 2 days (95%, $180,100 95% CI: $174,300, $186,000) and mechanical ventilation > 2 days (82%, $198,900 95% CI: $192.900, $205,000). Conclusions: Hospital costs of concurrent SS and AKI are higher than in any other subset of patients adjusting for inflation, patient demographics and clinical characteristics. AKI is a common complication in patients with SS and contributes to increased resource utilization and cost. Whether the use of treatment protocols for SS decreases occurrence of AKI and subsequently reduces the cost requires further investigation.