Validation of the multivariable In-hospital Mortality for PulmonAry embolism using Claims daTa (IMPACT) prediction rule within an all-payer inpatient administrative claims database.

Abstract

To validate the In-hospital Mortality for PulmonAry embolism using Claims daTa (IMPACT) prediction rule, in a database consisting only of inpatient claims. Retrospective claims database analysis. The 2012 Healthcare Cost and Utilization Project National Inpatient Sample. Pulmonary embolism (PE) admissions were identified by an International Classification of Diseases, ninth edition (ICD-9) code either in the primary position or secondary position when accompanied by a primary code for a PE complication. The multivariable IMPACT rule, which includes age and 11 comorbidities, was used to estimate patients' probability of in-hospital mortality and classify them as low or higher risk (≤1.5% deemed low risk). The rule's sensitivity, specificity, positive and negative predictive values (PPV and NPV) and area under the receiver operating characteristic curve statistic for predicting in-hospital mortality with accompanying 95% CIs. A total of 34,108 admissions for PE were included, with a 3.4% in-hospital case-fatality rate. IMPACT classified 11, 025 (32.3%) patients as low risk, and low risk patients had lower in-hospital mortality (OR, 0.17, 95% CI 0.13 to 0.21), shorter length of stay (-1.2 days, p<0.001) and lower total treatment costs (-$3074, p<0.001) than patients classified as higher risk. IMPACT had a sensitivity of 92.4%, 95% CI 90.7 to 93.8 and specificity of 33.2%, 95% CI 32.7 to 33.7 for classifying mortality risk. It had a high NPV (>99%), low PPV (4.6%) and an AUC of 0.74, 95% CI 0.73 to 0.76. The IMPACT rule appeared valid when used in this all payer, inpatient only administrative claims database. Its high sensitivity and NPV suggest the probability of in-hospital death in those classified as low risk by IMPACT was minimal.