Introduction

Over a decade after the implementation of the health care reform in Mexico, its intended impact on the coverage and healthcare utilization is still uncertain. Initial evaluations of Seguro Popular (Popular Health Insurance, SP by its Spanish acronym) showed that SP was reaching short-term objectives on population health and healthcare costs.¹ At first, at the household level, SP had positive impact on catastrophic health expenditures, which it reduced by approximately 6.7%.² Secondly, SP increased access to medical care utilization for people with diabetes and hypertension.^3,4 In contrast, recent studies have found that SP had little to no impact on diabetes and hypertension treatment and care among Mexican elders, and even produced an increase in ambulatory care sensitive hospitalizations (ACSH).^5,6

Effective preventive care for older adults can reduce health care costs and reduce multimorbidity and mortality.⁷SP provides a package of services that is limited in scope and availability since patients need to be treated via the SP network of health facilities.⁸ Compared to those without health insurance, people with SP have access to primary care, preventive screen ing procedures and specialty care, including routine screenings for people aged 20 or more years. In theory, low-income SP beneficiaries would be more likely to use preventive routine services than the uninsured. The main objective of this paper is to examine how the Mexican healthcare reform influences preventive care use among low-income older Mexicans (aged 50 to 75 years), including Pap smears, mammography/ clinical examination, and diabetes and hypertension screening. We focused on these illnesses because: 1) the high rates of these conditions in Mexico are attributed to the aging of the population; 2) these conditions are major causes of death among older adults in Mexico in 2011,⁹ and 3) there are high costs associated with the management and treatment of these conditions and related complications.^10,11

This paper expands the current literature on preven tive care utilization by using pseudo-panel data from Mexico to estimate the impact of SP. Although it has been shown that healthcare behaviors vary by ethnic groups, very little is known in regard to this topic among contemporary adults in Mexico. In an era where policy changes are implemented to improve the health of the aging population, it is imperative to critically discuss what is happening in other countries.

Materials and methods

We used data from three different sources: 1) the Mexi can Health and Nutrition Survey [Encuesta Nacional de Salud y Nutrición, Ensanut]; 2) the Mexican Census [In stituto Nacional de Estadística y Geografía; INEGI], and 3) the Mexican Department of Health Information (Sistema Nacional de Información en Salud; Sinais].

Firstly, individual characteristics were obtained from the Ensanut. We used repeated cross-sectional data from the 2000, 2006 and 2012 surveys. Ensanut uses a proba bilistic multistage stratified cluster sampling design, is nationally representative and includes participants from all the 32 states in Mexico. The protocol of Ensanut was approved by the Research, Ethics and Bio-security committees of the National Institute of Public Health.¹² Our sample included 17 640 adults aged 50 to 75 years, 5 506 in 2000, 4 947 in 2006, and 7 187 in 2012, who were enrolled in SP or did not have any type of health insur ance (the latter being a natural control group).¹³

In order to adjust for local level differences, state and regional characteristics, we obtained data from INEGI (http://www.inegi.org.mx/est/contenidos/Proyectos/ ccpv/default.aspx) and the National Health Information System (Sinais) (http://www.sinais.salud.gob.mx/basesdedatos/index.html) (variables in table I).

Results

Sample descriptive statistics by insurance status (SP or uninsured) and year of survey (2000, 2006 and 2012) can be seen in table II. The results show that the number of adults aged 50 to 75 years old insured through SP increased from 1 192 in 2006 to 5 037 in 2012. Yet, in 2012 there were 2 150 older people (30%) who were still uninsured. Although the most significant differences for this sample can be found in 2012, there were a few differences in both 2006 and 2012 between those with SP and those without health insurance. SP beneficiaries were more likely to be females and have primary edu cation. For both years, SP enrollees were less likely to be employed, had fewer family assets, and were more likely to reside in rural areas (these differences were significant at p≤ .05).

Table III presents a summary of those who per formed screening tests by year of survey and insurance status. Overall, it appears that the number of people performing preventive screening for diabetes, hyper tension, cervical and breast cancer has increased. There were significant differences between the uninsured and SP enrollees for most screening rates in 2006 and 2012, except for breast cancer screening, for which the rates differed only in 2006.

Table IV^23-25compares the results from the FEIV esti mations. We found that the main variable of interest SP insurance has no significant effect in the utilization of screening tests. Contrary to what one would expect based on evidence from other countries,^26,27SP beneficia ries were not significantly different from those without health insurance.

Discussion

This is the first study that used pseudo-panel data fixed-effects and instrumental-variables fixed-effects models to evaluate the impact of the SP program on preventive screening among older Mexican adults. In the initial results, SP appeared to be headed in the right direction in closing the gap in health care coverage for the poor. Descriptive statistics for 2012 showed that a higher percentage of older adults enrolled in SP were poor, unemployed and less educated. In addition, FE showed significant effects for SP (results not shown). Nevertheless, once a correction for endogeneity was implemented using a valid and relevant instrumental variable, the FEIV showed no difference for those with SP or the uninsured.

Our results are consistent with other researchers who have discussed poor impact of SP on population health due to organizational and structural issues in SP.^28,29,30 The federal and state governments have faced challenges when implementing SP -such as limited institutional capacity and information systems to over see productivity and quality-; these may be reflected in the perceived quality of care and impact healthcare utilization.³¹SP enrollees have reported dissatisfaction with their care because of the long distances they must travel to get to the clinics, the long waiting times to see a physician; the short duration of visits, the lack of bedside manner; and the short supply of medicines.^32,33 Older SP beneficiaries may not want to deal with these issues and delay seeking healthcare.

The current study has some limitations. Firstly, we used pseudo-panel data since longitudinal data are not available. However, we used a well-established approach proposed by Moffit.¹⁷ Secondly, Ensanut participants reported healthcare utilization measures and may have introduced recall bias. Furthermore, the questionnaire asked participants about their insurance status at the time of the survey, but healthcare utilization patterns referred to the previous year. Thirdly, due to the nature of the Ensanut, we were not able to separate mammograms from clinical examinations; instead, a composite measure was used. Finally, cervical and breast cancer screening guidelines have changed since 2000 and are continuously being updated worldwide;³⁴ Mexico has undergone similar changes.³⁵ However, in our search to assess the impact of SP across years, we were only able to compare screening utilization in the past 12 months of the survey. This limits our ability to accurately report the utilization of services.

Despite the limitations, the methods used are suf ficiently strong, and we found that preventive care for older low-income adults in Mexico did not differ be tween the SP-insured and the uninsured. These results have policy implications beyond Mexico. Although, SP may have made some progress in improving health care access and reducing out-of-pocket expenditures, effective access of health care and health care utilization remains a major issue.³⁶SP has achieved nearly universal health care coverage in Mexico; yet, as shown in this sample, there are still people who have no insurance. Furthermore, preventive services utilization is lower and not significantly different from that of older adults without health insurance. Additional efforts are needed to increase insurance coverage and healthcare quality, as well as to decrease healthcare disparities among older adults with a low income.