Acute pancreatitis: Trends in outcomes and the role of acute kidney injury in mortality- A propensity-matched analysis

Abstract

Objectives: To assess national trends of AP (acute pancreatitis) admissions, outcomes, prevalence of AKI (acute kidney injury) in AP, and impact of AKI on inpatient mortality.

Methods: We queried the Nationwide Inpatient Sample database from 2003 to 2012 to identify AP admissions using ICD-9-CM codes. After excluding patients with missing information on age, gender, and inpatient mortality, we used ICD-9-CM codes to identify complications of AP, specifically AKI. We examined trends with survey-weighted multivariable regressions and analyzed predictors of AKI and inpatient mortality by multivariate logistic regression. Additionally, both AKI and non-AKI groups were propensity-matched and regressed against mortality.

Results: A total of 3,466,493 patients (1.13% of all discharges) were hospitalized with AP, of which 7.9% had AKI. AP admissions increased (1.02%→1.26%) with rise in concomitant AKI cases (4.1%→11.7%) from year 2003-2012. Mortality rate decreased (1.8%→1.1%) in the AP patients with a substantial decline noted in AKI subgroup (17.4%→6.4%) during study period. Length of stay (LOS) and cost of hospitalization decreased (6.1→5.2 days and $13,654 to $10,895, respectively) in AKI subgroup. Complications such as AKI (OR: 6.08, p < 0.001), septic shock (OR: 46.52, p < 0.001), and acute respiratory failure (OR: 22.72, p < 0.001) were associated with higher mortality. AKI, after propensity matching, was linked to 3-fold increased mortality (propensity-matched OR: 3.20, P < 0.001).

Conclusion: Mortality, LOS, and cost of hospitalization in AP has decreased during the study period, although hospitalization and AKI prevalence has increased. AKI is independently associated with higher mortality.

Keywords: Acute renal failure; Complications; Inpatient; Mortality; Nationwide.