Is Social Vulnerability Associated with Surgical Site Infections in Trauma Patients?

Authors:
Lillian S Kao, Mokunfayo Fajemisin, Renee W, Green, Stephanie Martinez Ugarte, William Rieger

Body of Abstract:
Background: High social vulnerability, which integrates multiple indicators of social determinants of health, has been shown to be associated with increased trauma mortality and recurrent injuries. We hypothesized that social vulnerability, as measured by the Area Deprivation Index (ADI) is associated with an increased risk of surgical site infections (SSIs).

Methods: A retrospective cohort study was performed of trauma patients undergoing laparotomy procedures, age greater than 16, surviving greater than 48 hours, presenting to a single urban Level 1 trauma center from 2020 to 2021. Demographics, injury details, operative information and postoperative infectious outcomes were obtained from the trauma registry and supplemented by chart review. Social vulnerability was assessed using ADI which utilizes census-tract level information. The ADI has a maximum score of 100 and scores closer to 100 indicate increased social vulnerability. Outcomes of interest were organ-space surgical site infections (O-SSI), or any type of SSI associated with the trauma laparotomy. SSIs were classified per CDC definitions. Univariate and multivariable analyses were performed adjusting for age, gender, trauma mechanism, colonic injury, damage control laparotomy, and injury severity score (ISS).

Results: Among the 357 trauma patients undergoing laparotomy, the median age was 34.0 (IQR 11-57), and median ISS 22.0 (IQR 1-43.0). The majority of patients had a penetrating injury mechanism (57%) and were male (80%). Sixteen percent of patients underwent a damage control laparotomy, and 33% had a colonic injury. The median ADI was 65.0 (IQR 32- 98). Seventeen percent of patients (n=60) had OS-SSI and 19% (n=69) had any SSI. On univariate analysis, ADI was not associated with OS-SSI or any SSI. Similarly, on multivariable analysis, ADI was not associated with OS-SSI (OR 1.09, 95% 0.76-1.15, p=0.39) or any SSI (OR 1.01, 95% CI 0.92-1.06, p=0.71).

Conclusion: Social vulnerability, as defined by ADI, was not associated with OS-SSI or any SSI after trauma laparotomy. Injury characteristics and patient physiology may have more impact than social factors on SSIs after emergency trauma laparotomy. Additionally, more granular measures of social determinants of health may be needed to better elucidate any associations. Further research is needed in larger and less urban populations to determine if social vulnerability is associated with SSIs or affects any mediating factors such as time to source control.