Venous Thromboembolism after Inpatient Surgery in Administrative Data vs NSQIP: A Multi-Institutional Study

Background: Previous studies have documented significant differences between administrative data and registry data in the determination of postoperative venous thromboembolism (VTE). The goal of this study was to characterize the discordance between administrative and registry data in the determination of postoperative VTE. Study Design: This study was performed using data from the American College of Surgeons NSQIP merged with administrative data from 8 different hospitals (5 different medical centers) between 2013 and 2015. Occurrences of postoperative vein thrombosis (VT) and pulmonary embolism (PE) as ascertained by administrative data and NSQIP data were compared. In each situation where the 2 sources disagreed (discordance), a 2-clinician chart review was performed to characterize the reasons for discordance. Results: The cohort used for analysis included 43,336 patients, of which 53.3% were female and the mean age was 59.5 years. Concordance between administrative and NSQIP data was worse for VT (κ 0.57; 95% CI 0.51 to 0.62) than for PE (κ 0.83; 95% CI 0.78 to 0.89). A total of 136 cases of discordance were noted in the assessment of VT; of these, 50 (37%) were explained by differences in the criteria used by administrative vs NSQIP systems. In the assessment of postoperative PE, administrative data had a higher accuracy than NSQIP data (odds ratio for accuracy 2.86; 95% CI 1.11 to 7.14) when compared with the 2-clinician chart review. Conclusions: This study identifies significant problems in ability of both NSQIP and administrative data to assess postoperative VT/PE. Administrative data functioned more accurately than NSQIP data in the identification of postoperative PE. The mechanisms used to translate VTE measurement into quality improvement should be standardized and improved.