Abstract
The ‘Seguro Médico Siglo XXI’ (SMSXXI), a universal coverage medical insurance programme for children under 5 years of age, started in 2006 to help avoid catastrophic health expenditures in poor families without social security in Mexico. The study used information from the National Health Information System for the 2006–14 period. An ecological approach was followed with a panel of the 2457 municipalities of Mexico as the units of analysis. The outcome variables were the municipality-level neonatal mortality and infant mortality rates in population without access to social security. The programme variable was the coverage of the SMSXXI programme at the municipality level, expressed as a proportion. Demographic and economic variables defined at the municipality level were included as covariates. Impact was estimated by fitting a fixed-effects negative binomial regression model. Results reveal that the SMSXXI significantly reduced both infant and neonatSal mortality in the target population, although in a non-linear fashion, with minimum mortality levels found around the 70% coverage range. The effect is mostly given by the transition from the first quintile to the fourth quintile of coverage (<13% vs 70.5–93.7% coverage), and it is attenuated significantly at coverage levels very close to or at 100%. The observed risk reduction amounted to an estimated total of 11 358 infant deaths being avoided due to the SMSXXI during the 2006–14 period, of which 48% were neonatal. In conclusion, we found a significant impact of the SMSXXI programme on both infant mortality and neonatal mortality. An attenuation of the effect of the insurance on mortality rates at levels close to 100% coverage may reflect the saturation of health units in detriment of the quality of care.