Multimorbidity Confers Greater Risk for Older Patients in Emergency General Surgery Than the Presence of Multiple Comorbidities

BACKGROUND: Little is known about the impact of multimorbidity on outcomes for older emergency general surgery patients. OBJECTIVE: The aim was to understand whether having multiple comorbidities confers the same amount of risk as specific combinations of comorbidities (multimorbidity) for a patient undergoing emergency general surgery. RESEARCH DESIGN: Retrospective observational study using state discharge data. SUBJECTS: Medicare beneficiaries who underwent an operation for an emergency general surgery condition in New York, Florida, or Pennsylvania (2012-2013). MEASURES: Patients were classified as multimorbid using Qualifying Comorbidity Sets (QCSs). Outcomes included in-hospital mortality, hospital length of stay and discharge status. RESULTS: Of 312,160 patients, a large minority (37.4%) were multimorbid. Non-QCS patients did not have a specific combination of comorbidities to satisfy a QCS, but 64.1% of these patients had 3+ comorbid conditions. Multimorbidity was associated with increased in-hospital mortality (10.5% vs. 3.9%, P <0.001), decreased rates of discharge to home (16.2% vs. 37.1%, P <0.001), and longer length of stay (10.4 d±13.5 vs. 6.7 d±9.3, P <0.001) when compared with non-QCS patients. Risks varied between individual QCSs. CONCLUSIONS: Multimorbidity, defined by satisfying a specific QCS, is strongly associated with poor outcomes for older patients requiring emergency general surgery in the United States. Variation in risk of in-hospital mortality, discharge status, and length of stay between individual QCSs suggests that multimorbidity does not carry the same prognostic weight as having multiple comorbidities-the specifics of which are important in setting expectations for individual, complex patients.