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

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.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.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).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.