Measuring Institutional Strength: Seguro Popular Affiliation in Mexico from 2002 to 2006

RATIONALE: Since 2001, Mexico has designed and implemented a comprehensive health reform, an essential component of which is called Seguro Popular (SP). This program aims to provide medical care, preventative services, and financial protection to the approximately 50 million Mexicans without health coverage by 2010. The program intends to focus enrollment on the most vulnerable families - poor, rural, indigenous and female-headed households. Indeed, it mandates free insurance to all families in the poorest two income deciles, but requires contributions from enrollees with higher income. To encourage enrollment and improve service quality, Mexico's state ministries of health receive reimbursement for each affiliated family, along with separate funds to improve infrastructure in underserved areas. OBJECTIVES: This study evaluates each Mexican state's enrollment performance based on the ratio of actual versus expected affiliation. We also verify whether states fulfill their SP enrollment goals by corroborating official enrollment reports with household surveys and define the discrepancy between these data sources as effective affiliation. In addition, we calculate each state's payment gap, the number of families in the third income decile or above that receive coverage without having to pay. Finally, we investigate the household characteristics of families that forgo enrollment, even though they are eligible for free coverage. METHODS: Mexico's states differ markedly in socio-demographic variables and the timing of their association to the SP program. To compare each state's affiliation performance, we predict a family's probability of affiliation given household covariates. Multiple surveys are used to generate an expected number of affiliates: the Mexican 2005 Census, a state-representative health survey called ENSANut 2005-2006, and the 1-year follow-up survey in 7 states with especially intensive affiliation efforts. Then, we aggregate each family's probability of affiliation to generate a state's expected number of enrollees and calculate performance: the ratio of observed to expected affiliates. At the state level, we control for time associated to SP and already existing health infrastructure using SINERHAIS, a national database of health infrastructure. Data on official affiliation comes from the Padron del Seguro Popular 2002-2006, a registry of all affiliated individuals. RESULTS: By the beginning of 2006, Mexico had enrolled 2.3 million families in SP, about 10% of the nation. Nevertheless, affiliation performance differed significantly between states. The observed versus expected affiliation ratio was lowest for states that recently began enrollment. In addition, we found that effective affiliation remains significantly lower than official statistics, meaning that families are not taking full advantage of their SP benefits. Moreover, the payment gap was widest for the wealthiest states and those that began affiliation earliest. CONCLUSIONS: Mexico's recent initiative represents one of the largest health reforms in decades and has already improved social protection for many. However, these successes must not distract from continued enrollment of Mexico's most vulnerable citizens and improved data collection. The conclusions from this analysis can recommend changes both in Mexico and other nations seeking to improve health-system equity, efficiency, and population health.