Desigualdades sociais entre fatores de risco para a doença renal crônica na população brasileira: uma análise da Pesquisa Nacional de Saúde

Abstract

Introduction: Chronic kidney disease (CKD) is a major public health problem and one of the leading causes of morbidity and mortality in this century. Although the risk factors associated with CKD are well established and evidence indicates that populations with greater socioeconomic vulnerability are disproportionately exposed to these factors and their adverse outcomes, there are still few studies that assess inequalities in multiple risk factors for CKD, incorporating the intersection between gender and race, as well as studies that examine health patterns that potentially mediate the relationship between social disadvantage and CKD. Objectives: To assess social inequality in the distribution of risk factors for CKD among Brazilians and to explore health-related patterns that mediate the relationship between social disadvantage and CKD. Materials and methods: Cross-sectional study using the 2014-2015 National Health Survey Examination Database (n=8952). The prevalence of the following risk factors was assessed: diabetes, hypertension, dyslipidemia, obesity and overweight, excessive alcohol consumption, physical inactivity, smoking, and inadequate food consumption. Inequalities were measured by equity stratifiers (gender, color/race, region of residence, and education) and complex measures of inequality, including the angular index of inequity (SII) and the concentration index (CIX). Data were compared for the presence of CKD using the Student's t-test and chi-square test. Principal component factor analysis was performed to identify health-related patterns (mediators). Logistic regression models were performed to obtain odds ratios (OR) for the association between social disadvantage and CKD, and for the relationship between health-related patterns and the chance of CKD. The mediation model and other analyses were performed in Stata. Results: The prevalence of CKD was 5.3%. In the total population without CKD, most risk factors were concentrated among those with lower levels of education, with the exception of obesity (CIX= 3.10), excessive alcohol consumption (SII=5.50), and physical inactivity (SII=20.00). The population with CKD showed significant inequalities only for inadequate food consumption (SII = -27.30, CIX = -7.50) and hypertension (SII = -25.46) among those with lower levels of education, and physical inactivity (SII = 29.11) among those with higher levels of education. The analysis stratified by sex and color/race revealed initially hidden inequalities, showing that women of both colors/races and black-brown-indigenous men with DRC live with a higher burden of risk factors, with mixed levels of education, in addition to presenting the highest magnitudes of inequality found. There were no intersectional patterns of color/race in the inequalities of the group without DRC. Exposure to high socioeconomic disadvantage led to a 2.45-fold increase in the chance of DRC (OR: 2.45, 95% CI 1.23–4.89), which was mediated by 19.85% (95% CI 01.11–38.59) by high adherence to an unhealthy metabolic pattern. Conclusion: Substantial educational inequalities in the prevalence of clinical and behavioral risk factors were identified, especially among white and black-brown-indigenous women and black-brown-indigenous men with CKD in Brazil. The relationship between high social disadvantage and increased odds of CKD is partially mediated by the high presence of metabolic conditions among socially vulnerable individuals.