Importance: This study analyzes and reports Clostridium difficile infection (CDI) rates, risk factors, and associations with postoperative outcomes in the Veterans Health Administration (VHA).

Objective: To report 30-day postoperative CDI rates and outcomes and identify associated risks by surgical procedures and preoperative patient demographics in a large integrated health care system.

Design, setting, and participants: In a retrospective observational study conducted from September 2014 to April 2015, the Veterans Affairs Surgical Quality Improvement Program database and the Decision Support System pharmacy database were linked to analyze the association of postoperative CDI with patients' demographics, preoperative comorbidities, operative characteristics, and preoperative medications. The Veterans Affairs Surgical Quality Improvement Program assessments from October 1, 2009, to September 30, 2013, were investigated. The study was conducted at 134 VHA surgery programs, and the study population represents 12 surgical specialties: general, gynecological, neurosurgical, oral, orthopedics, otolaryngologic, plastic, podiatric, thoracic, transplant, urologic, and peripheral vascular.

Main outcomes and measures: Thirty-day postoperative CDI rates, risk factors of CDI, and association of CDI with postoperative morbidity and mortality.

Results: Among 468,386 surgical procedures, the postoperative CDI rate was 0.4% per year and varied by the VHA Surgery Program (0.0% to 1.4%) and surgical specialty (0.0% to 2.4%). Thirty-day CDI rates were higher in emergency procedures, procedures with greater complexity and higher relative value units, and those with a contaminated/infected wound classification. Patients with postoperative CDI were significantly older, more frequently hospitalized after surgery (59.9% vs 15.4%), had longer preoperative hospital stays (9.1 days vs 1.9 days), and had received 3 or more classes of antibiotics (1.5% vs 0.3% for a single antibiotic class) (all P < .001). Patients with CDI had higher rates of other postoperative morbidity (86.0% vs 7.1%), 30-day mortality (5.3% vs 1.0%), and longer postoperative hospital stays (17.9 days vs 3.6 days). Independent risk factors for CDI included commonly identified patient factors (albumin, functional class, and weight loss), procedural characteristics (complexity, relative value units, emergency, and wound classification), surgical program complexity, the number of preoperative antibiotic classes, and length of preoperative hospital stay.

Conclusions and relevance: The number and class of antibiotics administered after surgery, preoperative length of stay, procedural characteristics, surgical program complexity, and patient comorbidities are associated with postoperative CDI in the VHA.