Nationwide comparison of the medical complexity of patients by surgical specialty.

Abstract

Intuitively, the chronic disease burden of surgical patients varies considerably by surgical specialty, although sparse evidence in the literature supports this notion. We sought to characterize the medical complexity of surgical patients by surgical specialty and to quantify the association between medical complexity and outcomes. The National Inpatient Sample, an all-payer inpatient database representative of 97% of all U.S. hospitalizations, was used to identify adults undergoing surgery between 2005 and 2014. The most commonly performed operations that constituted 80% of each surgical specialty's practice were abstracted. The previously validated Elixhauser Comorbidity Index (ECI) was calculated per year by surgical specialty as a measure of medical complexity. Outcomes and resource utilization were assessed by comparing mortality rate, length of stay, and cost. An estimated 53,232,144 patients underwent operations in one of nine surgical specialty categories. Surgical specialties were ranked by ECI, with cardiac surgery (3.56), vascular surgery (3.49), and thoracic surgery (2.86) having the highest mean ECI (all P values <.0001 compared with vascular surgery). Whereas the high ECI scores in cardiac surgery were driven by arrhythmias and hypertension, vascular patients had a more uniform distribution of comorbidities. The average ECI for all surgical patients increased during the study period from 2.03 in 2005 to 2.65 in 2014 (P < .001), with a similar trend for all specialties considered. Unlike the two specialties with the lowest burden of comorbidities (orthopedic surgery and endocrine surgery), cardiac surgery and vascular surgery exhibited significantly higher inpatient mortality, LOS, and costs. Although all surgical patients have exhibited an increase in comorbidities during the past decade, candidates for cardiac and vascular operations appear to carry the largest burden of chronic conditions. Despite caring for patients with the highest burden of comorbidities for emergent operations, vascular surgery did not have the highest mortality, inpatient costs, or length of stay compared with some of the other specialties. The intensity of care and assumed risk in treating medically complex vascular patients should be taken into consideration in deciding health policy, reimbursement, and hospital resource allocation.