LAUSR

Background: Surveillance programs have proven to be effective in reducing surgical site infection (SSI) rates. In 2008 Piedmont, which is a northwestern region of Italy, joined the Italian national surveillance system (Sistema Nazionale Sorveglianza Infezioni del Sito Chirurgico [SNICh]). The aims of this study were to evaluate SSI rates and trends in Piedmont from 2009 to 2015 for the two most frequently performed surgical procedures, hip arthroplasty and colon surgery, and to estimate whether the number of years of participation in a surveillance program and the number of monitored surgical procedures have an impact on the incidence of SSIs. Methods: Data were collected through the national surveillance system. Procedure-specific SSI rates were calculated, overall and by year of participation in the network. Trends in SSI rates were evaluated in relation to the duration of surveillance and the number of monitored procedures using Poisson regression analysis. Results: A total of 16,288 procedures were monitored from 37 hospitals. The overall adjusted SSI rates were 8.61% after 6,050 colon surgery procedures and 1.16% after 10,238 hip arthroplasty procedures. Each year of increase in participation was associated with a substantial risk reduction for SSI in both procedure categories: 7% for colon surgery (risk ratio [RR] 0.93; 95% confidence interval [CI] 0.89-0.97) and 20% (RR 0.80; 95% CI 0.73-0.88) for hip arthroplasty. Conversely, an increase in the number of monitored procedures was not associated with a substantial decrease in SSI risk: an overall RR of 0.99 (95% CI 0.98-1.00) and 1.00 (95% CI 0.99-1.00) was found for every one unit increase in the number of monitored procedures for colon surgery and hip arthroplasty respectively. Conclusions: These results support the efficacy of systematic surveillance in reducing SSIs, increasing with the number of years of participation, and suggest the volume of monitored procedures has no significant impact on SSI risk.