Social Deprivation and Postoperative Mortality

Socioeconomic factors are associated with differences in health outcomes, but their impact on surgical patients is still not well understood, especially in low- and middle-income countries. Social deprivation may affect perioperative outcomes through differences in access to healthcare, burden of comorbidities, timing of care, and hospital resources. However, few studies have evaluated this association in large and diverse surgical populations, and data from Brazil are limited.

This retrospective multicenter cohort study will evaluate the association between socioeconomic deprivation and perioperative outcomes among patients undergoing surgery in Brazil. The study will include patients aged 16 years or older who underwent elective or urgent surgical procedures in participating public and private hospitals between January 1 and December 31, 2024. Patients undergoing ophthalmologic procedures, diagnostic procedures, procedures performed under local anesthesia only, selected transplant procedures, and organ donors after brain death will be excluded.

Socioeconomic deprivation will be assessed using georeferenced area-level indices derived from each patient's residential address, including the Brazilian Deprivation Index, the Social Vulnerability Index, and the Municipal Human Development Index. The researchers will grou patients according to deprivation levels, and analyze the association between deprivation and postoperative outcomes.

The primary outcome will be 30-day in-hospital postoperative mortality. The study will also evaluate demographic, clinical, surgical, and hospital-level factors associated with mortality, including age, sex, ethnicity, American Society of Anesthesiologists physical status classification, surgical urgency, surgical magnitude, surgical specialty, and type of healthcare system. Multivariable logistic regression models will be used to assess whether socioeconomic deprivation is independently associated with postoperative mortality after adjustment for relevant clinical and surgical factors.

The results of this study may improve the understanding of how socioeconomic deprivation influences perioperative risk in Brazil. The findings may help identify vulnerable surgical patients, support risk prediction models that include social determinants of health, and inform strategies to reduce inequities in perioperative care.