Risk Factors for Abdominal Incision Infection after Colorectal Surgery in a Saudi Arabian Population : The Method of Surveillance Matters

Background: Reported surgical site infection rates range from 2.1% to 40% after colorectal surgery and are believed to be underestimated depending on the method of surveillance. The study aims were to identify an accurate incidence and associated risk factors for abdominal incision surgical site infection after elective open colorectal surgery in a Saudi population. Methods: This was a prospective observational longitudinal study of 300 consecutive adult patients, recruited upon admission to an 800-bed tertiary referral center. All consenting adults admitted for elective open colorectal surgery were included. Patients were followed for 36 d post-surgery by two certified and experienced wound care experts who diagnosed abdominal incision surgical site infections. The definition provided by the U.S. Centers for Disease Control and Prevention was used. Statistical analysis was performed using both univariate and multivariable logistic regression. Results: Data were analyzed for 296 patients; the incidence of abdominal surgical site infection was 30%. Factors associated with surgical site infection by univariate analysis were pre-operative pre-albumin (p = 0.04, odds ratio [OR] 0.81, 95% confidence interval [CI] 0.66–0.99); operative difficulty because of truncal obesity (p = 0.006, OR 2.19, 95% CI 1.25–3.84) and obesity measured by body mass index (p = 0.002, OR 4.00, 95% CI 1.95–8.20). Multivariable analysis identified only two significant risk factors: Pre-operative pre-albumin (p = 0.02, OR 0.76, 95% CI 0.60–0.96), and obesity measured by body mass index (BMI; p = 0.001, OR 4.71, 95% CI 2.20–10.10). Conclusion: Obesity and nutritional status correlated with post-operative abdominal surgical site infection. The method of surveillance and length of follow-up impact the rate reported. Acolorectal surgical database at the authors’ facility had shown abdominal incision infection rates after open colorectal surgery to be 12%, whereas hospital infection control data demonstrated a colorectal surgical site infection (SSI) rate of 1%–11%. Studies internationally have reported a wide variation in rates ranging from 2.1% to 27.6% [1–13]. Moreover, the cost per infection is reported as high as $17,000 in the United States [14] and £10,000 in the United Kingdom [12]. In addition to financial consequences, reduced patient satisfaction and quality of life have been the impetus to benchmark surgical site infection rates as a measure of quality of care [15,16]. It is recognized that factors contributing to SSI are not only surgeon-dependent but patient and procedure-dependent. It is known that the endogenous bacteria encountered at the time of surgery, including its virulence and the patients’ ability to mount an immune response, play an important role [17,18]. Failure of evidence-based guidelines to reduce infection rates significantly over the last decade also suggests the influence of differences in surveillance methods and patient populations. There has been much debate surrounding controllable versus uncontrollable risk factors and risk stratification [19], particularly in colorectal surgery where incidence rates have not improved substantially. Bull et al. [20] found that maintaining normothermia, normoglycemia, increasing oxygen delivery, and ensuring appropriate antibiotic use halved SSI rates, whereas other similar improvement projects have not demonstrated the same success [21]. It has been postulated that the contribution of patient characteristics needs further consideration in the colorectal surgery population [11,22–26]. It is reported that diabetes mellitus rates in the Saudi population are higher than in other populations [27]; additionally, Colorectal Therapy, Department of Nursing, Colorectal Surgery, Department of Surgery, King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia. SURGICAL INFECTIONS Volume XX, Number X, 2015 a Mary Ann Liebert, Inc. DOI: 10.1089/sur.2013. 208