Related Experiment Video
Updated: Oct 13, 2025

Inverse Probability of Treatment Weighting Propensity Score using the Military Health System Data Repository and National Death Index
Published on: January 8, 2020
The income gradient in COVID-19 mortality and hospitalisation: An observational study with social security
Eva O Arceo-Gomez1, Raymundo M Campos-Vazquez2, Gerardo Esquivel3
1Universidad Iberoamericana, Mexico City, Mexico.
Background:
The COVID-19 pandemic revealed large structural inequalities that led to disparities in health outcomes related to socioeconomic status. So far, most of the evidence is based on aggregated data or simulations with individual data, which point to various possible mechanisms behind the association. To date, there have been no studies regarding an income gradient in COVID-19 mortality based on individual-level data and adjusting for comorbidities or access to healthcare.
Methods:
In this paper, we use linked employee-patient data for patients tested for COVID-19 at the Mexican Institute of Social Security. We estimate the association of the probability of dying with income centiles, using a probit estimation and adjusting for COVID-19 diagnosis, sociodemographic variables, and comorbidities.
Findings:
After controlling for all these variables, we find that persons in the lowest income decile still had a probability of dying from COVID-19 five times greater than those at the top decile.
Interpretation:
Our results imply that the association between income and COVID outcomes is not explained by the prevalence of comorbidities or by a lack of access to healthcare among the low-income population.
Funding:
This study was not supported by any external funding source.
Related Concept Videos
Bias in Epidemiological Studies
Pareto Chart
The Pareto chart is named after the Italian economist Vilfredo Pareto, who described the Pareto...
Statistical Methods for Analyzing Epidemiological Data
Comparing the Survival Analysis of Two or More Groups
Relative Risk
Wilcoxon Signed-Ranks Test for Median of Single Population

