COVID-19 cases, hospitalizations, outpatients, and deaths in Mexico by ethnicity and state-level income.

Introduction: Mexico is one of the countries that is most affected by mortality due to COVID-19. Once infected, the indigenous population living in the lower-income states had worse outcomes. Our objectives were to analyze outcomes by ethnic group, and determine the association between state-level income and the incidence, hospitalizations, outpatients, and death rates per 100,000 population.

Methodology: We analyzed 1,037,567 confirmed COVID-positive cases from February 29 to November 13, 2020 recorded in the Mexican COVID-19 cases database. Sociodemographic characteristics, comorbidities, and outcomes were analyzed. Data was allocated according to the state where the patients were treated. Statistical association between age-adjusted incidence and death rates with state-level GDP per capita (as a measure of income), were ascertained using Spearman correlations. Kruskal-Wallis tests examine the association of cumulative incidence, hospitalizations, outpatients, and death rates, with income quartiles. When significant, a follow-up analysis (Mann-Whitney) was conducted.

Results: Respective cumulative incidence rates and death rates were: 900.3 (non-indigenous) and 94.4 (indigenous), and 87.1 (non-indigenous) and 13.9 (indigenous). Spearman correlation coefficients of income with age-standardized incidence and death rates were 0.657 and 0.607 (p < 0.001 for both). Kruskal-Wallis H-Values indicate significant median differences by income in total population rates: cumulative incidence 13.47 (p < 0.01), hospitalizations 11.67 (p < 0.01), outpatients 12.86 (p < 0.01), and deaths 8.92 (p < 0.05).

Conclusions: Cumulative incidence, hospitalizations, outpatients, and mortality rates presented a reversed socioeconomic status health gradient in Mexico. Less adverse outcomes were observed in the lowest-income states compared to higher-income states.