Emergency Surgery, Multimorbidity and Hospital-Free Days: A Retrospective Observational Study

Analyzing hospital-free days (HFDs) offers a patient-centered approach to health services research. We hypothesized that, within emergency general surgery (EGS), multimorbidity would be associated with fewer HFDs, whether patients were managed operatively or nonoperatively.

EGS patients were identified using national Medicare claims data (2015-2018). Patients were classified as multimorbid based on the presence of a Qualifying Comorbidity Set and stratified by treatment: operative (received surgery within 48 h of index admission) and nonoperative. HFDs were calculated through 180 d, beginning on the day of index admission, as days alive and spent outside of a hospital, an Emergency Department, or a long-term acute care facility. Univariate comparisons were performed using Kruskal-Wallis tests and risk-adjusted HFDs were compared between multimorbid and nonmultimorbid patients using multivariable zero-inflated negative binomial regression models.

Among 174,891 operative patients, 45.5% were multimorbid. Among 398,756 nonoperative patients, 59.2% were multimorbid. Multimorbid patients had fewer median HFDs than nonmultimorbid patients among operative and nonoperative cohorts (P < 0.001). At 6 mo, among operative patients, multimorbid patients had 6.5 fewer HFDs (P < 0.001), and among nonoperative patients, multimorbid patients had 7.9 fewer HFDs (P < 0.001). When length of stay was included as a covariate, nonoperative multimorbid patients still had 7.9 fewer HFDs than nonoperative, nonmultimorbid patients (P < 0.001).

HFDs offer a patient-centered, composite outcome for claims-based analyses. For EGS patients, multimorbidity was associated with less time alive and out of the hospital, especially when patients were managed nonoperatively.