Assessment of the Impact of Socioeconomic Factors on Perioperative Outcomes

Socioeconomic deprivation is a multidimensional determinant of health that may influence perioperative outcomes through several pathways, including differences in baseline health status, burden of comorbidities, access to timely healthcare, perioperative optimization, and hospital-level resources. Although previous studies have suggested an association between social deprivation and worse postoperative outcomes, most available evidence comes from high-income countries or from studies focused on specific surgical populations. Data from low- and middle-income countries, including Brazil, remain limited.

This study is a retrospective, multicenter cohort study designed to assess the association between socioeconomic deprivation and perioperative outcomes among surgical patients treated in Brazilian hospitals. Participating centers will include both public and private hospitals from different regions of the country. The study will use routinely collected institutional data from patients who underwent surgical procedures during the 2024 calendar year. No additional contact, intervention, or change in clinical care will occur as part of the study.

The main exposure of interest is socioeconomic deprivation, assessed through georeferenced area-level indicators based on each patient's residential address. Residential addresses will be geocoded to identify the corresponding census tract or human development unit. Socioeconomic deprivation will then be measured using validated Brazilian indices, including the Brazilian Deprivation Index, the Social Vulnerability Index, and the Municipal Human Development Index. These indices capture different dimensions of socioeconomic context, including income, education, household conditions, urban infrastructure, human capital, and vulnerability related to work and income.

The study database will include demographic, clinical, surgical, and structural variables routinely available in hospital electronic records. These variables include age, sex, ethnicity, American Society of Anesthesiologists physical status classification, educational level, occupation, surgical procedure, surgical urgency, date of surgery, date of hospital discharge or in-hospital death, surgical specialty, surgical magnitude, and type of healthcare system. Surgical procedures will be standardized using Brazilian procedural classification systems (Classificação Brasileira Hierarquizada de Procedimentos Médicos -CBHPM). If a patient undergoes more than one eligible surgical procedure during the study period, only the first procedure will be considered for outcome analysis.

Data will be extracted locally by the information technology teams of participating centers using structured database queries. Identifiable patient information will not be included in the analytical dataset. Residential addresses will be used only for geocoding and linkage to area-level socioeconomic indices. After geospatial processing, the final research dataset will exclude full residential addresses and other direct identifiers. Access to study data will be restricted to authorized members of the research team, and data will be stored in a secure institutional environment.