An evaluation of differences in risk factors for individual types of surgical site infections after colon surgery

Most studies and national programs aggregate the different types of surgical site infections (SSIs) potentially masking and misattributing risk. Determining that risk factors for superficial, deep, and organ space SSIs are unique is essential to improve SSI rates.

This cohort study utilized data of 59,365 patients who underwent colon resection at hospitals participating in the American College of Surgeons National Surgical Quality Improvement Program from 2007 to 2009. Four independent, multivariable, predictive models were developed to assess the unique associations between risk factors and each SSI group: Superficial, deep, organ space, and an aggregate of all 3 types of SSIs.

Overall, 13% of colon cases developed SSIs: Superficial (8%), deep (1.4%), and organ space (3.8%). Each model was different. Morbidly obese patients were more likely to develop SSIs than normal weight patients across all models; however, risk factors common to all models (eg, body mass index [BMI], duration of operation, wound class, laparoscopic approach) had very different levels of risk. Unique risks for superficial SSIs include diabetes, chronic obstructive pulmonary disease, and dyspnea. Deep SSIs had the greatest magnitude of association with BMI and the greatest incidence of wound disruption (19.8%). Organ space SSIs were often owing to anastomotic leaks and were uniquely associated with disseminated cancer, preoperative dialysis, preoperative radiation treatment, and a bleeding disorder, suggesting a physically frail or compromised patient may put the anastomosis at risk.

Risk factors for superficial, deep, and organ space SSI differ. More effective prevention strategies may be developed by reporting and examining each type of SSI separately.