High-Risk Comorbidity Combinations in Older Patients Undergoing Emergency General Surgery.

BACKGROUND/OBJECTIVES: Over a million older patients in the United States are admitted yearly for emergency general surgery (EGS) conditions. Seven procedure types dominate: colon, small bowel, gallbladder, ulcer disease, adhesiolysis, appendix, and laparotomy operations. A higher comorbidity burden is known to increase mortality in this population, but the impact of specific comorbidity combinations is unknown. Our objectives were to (1) characterize the distribution of procedures, comorbidities, and outcomes for older patients undergoing EGS; and (2) apply a data-driven approach (association rule mining) to identify comorbidity combinations associated with disproportionately high mortality.

DESIGN, SETTING, AND PARTICIPANTS: Cross-sectional study of patients 65 years and older who underwent one of the seven procedures previously cited, taken from the 2011 Nationwide Inpatient Sample. A total of 280 885 patient encounters were identified.

MEASUREMENTS: In-hospital mortality, procedures, and comorbidities based on the Elixhauser Comorbidity Index.

RESULTS: Overall mortality was 5.6%. The most common procedures were gallbladder (33.7%), ulcer surgery (21.5%), and adhesiolysis (21.0%). Mortality increased for all procedures as patients aged. Comorbidities associated with the highest mortality included coagulopathy (adjusted odds ratio [aOR] = 3.74; 95% confidence interval [CI] = 3.41-4.11; p < .001), fluid and electrolyte disorders (FED) (aOR = 2.89; 95% CI = 3.66-3.14; p < .001), and liver disease (aOR = 1.89; 95% CI = 1.61-2.22; p < .001). Three-way comorbidity combinations most highly associated with mortality were coagulopathy, FED, and peripheral vascular disease (aOR = 5.10; 95% CI = 4.17-6.24; p < .001), and coagulopathy, FED, and chronic pulmonary disease (aOR = 4.83; 95% CI = 4.00-5.82; p < .001).

CONCLUSION: For older patients, combinations of comorbidities portend additional risk beyond single comorbidities, and the associated risk burden is driven by the specific constellation of comorbidities present. Future work must continue to examine the effect of co-occurring diseases to provide personalized and realistic prognostication for older patients undergoing EGS.