title: Heterogeneous effects of health insurance on out-of-pocket expenditure on medicines in Mexico.
abstract: OBJECTIVE
  Given the importance of health insurance for financing medicines and recent policy changes designed to reduce health-related out-of-pocket expenditure (OOPE) in Mexico, our study examined and analyzed the effect of health insurance on the probability and amount of OOPE for medicines and the proportion spent from household available expenditure (AE) funds.
  
  
  METHODS
  We conducted a cross-sectional analysis by using the Mexican National Household Survey of Income and Expenditures for 2008. Households were grouped according to household medical insurance type (Social Security, Seguro Popular, mixed, or no affiliation). OOPE for medicines and health costs, and the probability of occurrence, were estimated with linear regression models; subsequently, the proportion of health expenditures from AE was calculated. The Heckman selection procedure was used to correct for self-selection of health expenditure; a propensity score matching procedure and an alternative procedure using instrumental variables were used to correct for heterogeneity between households with and without Seguro Popular.
  
  
  RESULTS
  OOPE in medicines account for 66% of the total health expenditures and 5% of the AE. Households with health insurance had a lower probability of OOPE for medicines than their comparison groups. There was heterogeneity in the health insurance effect on the proportion of OOPE for medicines out of the AE, with a reduction of 1.7% for households with Social Security, 1.4% for mixed affiliation, but no difference between Seguro Popular and matched households without insurance.
  
  
  CONCLUSIONS
  Medicines were the most prevalent component of health expenditures in Mexico. We recommend improving access to health services and strengthening access to medicines to reduce high OOPE.
authors.affiliation: Center for Health Systems Research, National Institute of Public Health, Cuernavaca, Mexico.
authors.forename: Veronika J
authors.initials: VJ
authors.lastname: Wirtz
authors.forename: Yared
authors.initials: Y
authors.lastname: Santa-Ana-Tellez
authors.forename: Edson
authors.initials: E
authors.lastname: Servan-Mori
authors.forename: Leticia
authors.initials: L
authors.lastname: Avila-Burgos
mesh_terms: D000328:Adult; D000368:Aged; D017047:Cost Sharing / Q000706:statistics & numerical data*; D003430:Cross-Sectional Studies; D003625:Data Collection; D005260:Female; D005102:Health Expenditures / Q000706:statistics & numerical data*; D006297:Health Services Accessibility / Q000191:economics*; D006801:Humans; D019458:Insurance Coverage / Q000706:statistics & numerical data*; D007348:Insurance, Health / Q000706:statistics & numerical data*; D016014:Linear Models; D008297:Male; D017057:Medically Uninsured / Q000706:statistics & numerical data*; D008800:Mexico; D008875:Middle Aged