Surgical Site Infections (SSIs) represent one of the main causes of morbidity and mortality among Healthcare-Associated Infections (HAIs), accounting for about 20% of HAIs, prolonging hospital stays, negatively impacting patient recovery, and generating high hospital costs. This study aimed to analyze the temporal evolution of SSI rates in a tertiary teaching hospital between 2011 and 2024, identifying trends, seasonality, and possible change points through time series and segmented regression. An ecological, retrospective study was conducted based on aggregated secondary data from the Hospital Infection Control Committee of a tertiary hospital. All surgeries performed at the tertiary hospital from January 2011 to November 2024 were included. Monthly SSI rates were evaluated through time series analysis (STL decomposition) and the Mann-Kendall trend test. Segmented regression (Joinpoint) was also applied to detect changes in slope of trends. Analyses were performed using R and Joinpoint software. A total of 106,171 surgeries were analyzed, with an overall trend of reduction in SSI rate from 9.9% (2011) to 5.6% (2024). The Mann-Kendall test indicated a statistically significant decreasing trend in overall SSI rate (tau = −0.46; p < 0.0001) and in clean surgery rates (tau = −0.16; p = 0.0023). STL decomposition revealed strong annual seasonality and a sustained downward trend, with more discrete oscillations in clean surgeries. Joinpoint regression for the overall series did not identify inflection points, indicating constant decline (Estimated monthly percent variation (MPV) = −0.0261%/month; p < 0.0001). In clean surgeries, there was a significant decrease until 2015 (MPV = −0.0702%/month; p = 0.001), followed by a period without significant variation until the end of the series (p = 0.576). SSI rates showed a progressive and statistically significant decline between 2011 and 2024 in a tertiary hospital, with maintenance of seasonal patterns. The stability observed in clean surgeries after 2015 suggests consolidation of institutional HAI prevention practices. The findings reinforce the importance of continuous surveillance and strategies adapted to the temporal profile of SSIs.
Cruz et al. (2026) studied this question.