Access to health care services between insured and uninsured older 50 adults with diabetes in Mexico: The Mexican Health and Aging Study (MHAS-2018)

Abstract

Aim−

Analyze the association between health insurance coverage and the use of health care services, dentist visits, and self-medication in a national sample of 50-year-old Mexican adults with diabetes.

Methods−

Participants with diabetes taken from a subsample of the Mexican Health and Aging Study (MHAS-2018) (n=3,667) were examined, with data pertaining to the frequency of their doctor and dentist visits, residence, years of education, self-medication, and health insurance coverage (insured/uninsured) also collected. A logistic regression model was used to identify the association between independent variables and health insurance coverage, while Poisson regression models were also estimated to ascertain whether health insurance coverage was associated with the number of doctor and dentist visits.

Results−

The prevalence of self-reported diabetes was 24.6%, while approximately 93.3% of subjects had visited a doctor, 40.6% had visited a dentist, and 20.3% self-medicated. Individuals with insurance coverage were 75% (OR=1.75 [1.32 – 2.31]; p<0.001) more likely to have visited a doctor and 57% more likely to have visited a dentist (OR=1.57 [1.35 – 1.83]; p<0.001) than uninsured adult subjects, while adults living in rural areas were 77% less likely to be insured than adults living in urban areas. Doctor and dentist visits [RR=1.32 (1.28 – 1.35); p<0.001] and [RR= 1.47 (1.37 – 1.58); p<0.001, respectively] were found to be positively associated with the insured members of the study population.

Conclusion-

A positive association was found between doctor and dentist visits in the population insured with diabetes. A major public health challenge is the population of diabetics who report being uninsured, wherein this population requires coverage in order to access the necessary clinical follow-up and control to prevent complications.

Introduction

According to the International Diabetes Federation, approximately 463 million people aged 20–79 years have diabetes worldwide, representing 9.3% of the world population in this age group, an estimated 79.4% of whom live in low and middle-income countries.¹ Based on diabetes estimates and projections, the total number of diabetes patients is expected to increase to 578 million (10.2%) by 2030 and to 700 million (10.9%) by 2045.¹

The Americas and Caribbean Region is home to an estimated 47.6 million people with diabetes, with 34.1 million adults over 18 years of age (13.0%) estimated to have diabetes in the United States.² According to the Encuesta Nacional de Salud y Nutrición (ENSANUT, or the National Health and Nutrition Survey) 2018, the prevalence of diabetes in Mexico was 10.3% in adults over 20 years of age.³

Health protection systems have been developed in most countries around the world with the aim of achieving universal coverage in the population. As the way people live and work has an impact on their health, it is important to recognize the social determinants of health in order to improve health outcomes in the population.⁴

It has been observed that health insurance coverage causes improvements in chronic health problems by increasing access to health services.⁵ Similarly, access to health services enables people to receive care when they need it and to learn about disease prevention, thus increasing their productivity and contributing to the well-being of their families and communities.

US studies have observed an increase in health coverage among adults with diabetes aged 18 to 64 years, coverage of health insurance increased from 84.7% in 2009 to 90.1% in 2016 also shows that coverage remained almost universal for those over 65 (99.5%).⁶ Additionally, it was found that health insurance coverage and improvements in the quality of coverage can improve health outcomes among older adults with diabetes.⁷

According to data taken from ENSANUT-2018, 102.3 million Mexicans have access to health services, (comprising 83% of Mexican women and 78.8% of Mexican men), corresponding to an increase on the 39.8 million and 85.8 million insured Mexicans found by the National Health Survey 2000 and ENSANUT-2012, respectively.⁸ This increase represents significant progress for Mexico’s Social Protection System in Health.⁹ As diabetes and its clinical complications have consequences on both Mexico’s population and economy, there is a need to measure disparities in access to healthcare services in the diabetic population, as reducing such disparities can have a positive impact on chronic health problems, decreasing both morbidity and mortality indicators, among others. The purpose of the present study was to analyze the association between health insurance coverage and the use of healthcare services, dentist visits, and self-medication in a national sample of 50-year-old Mexican adults with diabetes.

Materials and methods

The Mexican Health and Aging Study (MHAS) 2001 comprises five rounds of a nationally representative prospective panel study of adults born before 1951 and is representative of both urban and rural environments. The MHAS surveys are conducted under the supervision of coordinators from both Mexico and the United States and are partially funded by the National Institute of Aging at the United States’ National Institutes of Health (NIH R01AG018016) and Mexico’s Instituto Nacional de Estadística y Geografía (INEGI or National Institute of Statistics and Geography). The MHAS data files and documentation are available for public use at www.ENASEM.org.¹⁰ The present study was approved, in the United States, by the Institutional Review Boards and Ethics Committees at the University of Texas Medical Branch and, in Mexico, by INEGI and the National Institute of Public Health. Moreover, the present study adhered to the ethical guidelines set out in the Declaration of Helsinki and obtained signed informed consent from all participants and their next-of-kin.

The primary objective of the MHAS is to collect information from a broad representative panel of the Mexican population aged 50 years and over, in order to enable the examination, from a broad socioeconomic perspective, of the aging process and the disease and disability burden it bears.¹¹ Since the compilation of baseline data in 2001, follow-up data has been collected by the MHAS in 2003, 2012, and 2015. A fifth wave of data was collected, in 2018, on the 2001 baseline cohort (born in 1951 or earlier), the 2012 cohort (born in 1952–1962), and a new cohort of people born between 1963 and 1968, which was added to update the sample.

The thematic content of the MHAS survey instrument included the following: demographic data; household residents and children’s rosters; self-reported health in several dimensions (chronic diseases, perceived global health, physical function, cognition, and depression); information on parents and children; help received from and given to children; institutional support; life satisfaction; time use; social support and social engagement; dwelling conditions; and, economic aspects, such as health expenditures, health insurance coverage, pensions received or expected, income by source, and the value of accumulated assets.¹²

Study population

Of a sample of 4,193 individuals who reported having diabetes to MHAS-2018, 526 were excluded due to missing responses, leaving a final sample of 3,667 diabetic adults aged 50 years and older, with no differences observed between the demographic data obtained from the missing and complete responses pertaining to adults aged 50 and over. Adults were classified as having self-reported diagnosed diabetes (hereafter termed “diabetes”) if they answered “yes” to the question “Has a doctor or medical personnel ever diagnosed you with diabetes?”

Variables

The independent variables were as follows: age (years) and categorized in three groups (50–59, 60–69, and ≥70 years); sex (male/female); doctor visits (yes/no); doctor visits (number of times); dentist visits (yes/no); dentist visits (number of times); self-medication (in consultation with a pharmacist) dichotomized into yes/no; health status (excellent/very good/good/fair/poor); comorbidities, such as high blood pressure (yes/no), arthritis (yes/no), and vision problems (yes/no); and, place of residence (urban/rural). In Mexico, a rural locality is classified as having a population of less than 2,500 inhabitants.¹³

The variable of years of education was used to compare those adults who had completed nine years of formal education or more with those who had completed less than nine years, which, in Mexico, corresponds to elementary and lower secondary school combined and was dichotomized by the present study into < 9 years and ≥ 9 years. Information regarding diabetes control was obtained by means of a standardized questionnaire, which included the following questions: Are you currently taking any oral medication in order to control your diabetes? (yes/no); Are you currently using insulin shots? (yes/no); Do you follow a special diet to control your diabetes? (yes/no); In general, is your diabetes under control now? (yes/no); and, How frequently do you measure your blood sugar level or urine-sugar level? (number of times).

The Mexican health system comprises the public and private sectors, with the former formed by institutions providing healthcare via contribution-based public medical insurance programs such as: Instituto Mexicano del Seguro Social (IMSS or Mexican Institute of Social Security); Instituto de Seguridad y Servicios Sociales de los Trabajadores del Estado (ISSSTE or Institute of Security and Social Services for State Workers); Petroleos Mexicanos (PEMEX or Mexican Petroleum); Secretaria de Defensa Nacional (SEDENA or Ministry of Defense); and, Secretaria de Marina (SEMAR or Ministry of the Navy). Both ISSSTE and IMSS organize, provide and regulate most of their own health services through vertically integrated, national organizations. Other hand, the SEDENA, SEMAR and the oil company PEMEX, fund and provide health services for their forces and employees, respectively.¹⁴

On the other hand, there are the institutions and programs that serve the population without health insurance coverage such as: Secretaria de Salud (SSa or Ministry of Health); Servicios Estatales de Salud (SESA or State Health Services); the IMSS-Oportunidades program (IMSS-O or IMSS-Opportunities); and, Seguro Popular (SP) now Instituto Nacional de Salud para el Bienestar (INSABI or National Health Institute for Welfare).¹⁵ SP the major financial protection scheme for those outside social insurance arrangements and the unemployed, providing limited health services. Health services are provided mostly by SSa at state and federal levels, with access and quality limitations in spite of funding efforts by Seguro Popular and now by the Institute for Health for Wellbeing (INSABI) that replaced it.¹⁴ INSABI covers approximately 69 million Mexicans without social security. Those not covered by INSABI and even those protected by other health insurance programmes are able to pay out-of-pocket to use SSa hospitals and state medical facilities according to a scale related to income.¹⁴ The present study defined health insurance coverage as being in receipt of insurance coverage under the IMSS, ISSSTE, SEMAR, SEDENA, and PEMEX programs and not via the SSa, SP (INSABI), or private insurance.

Statistical analysis

Comparisons between insured and uninsured subjects were undertaken by age group, sex, residence, years of education, health status, doctor and dentist visits, self-medication categories, as well as the questions related to diabetes, while the Pearson’s Chi-square test was used for categorical variables. The association between the dependent variable of health insurance coverage (insured/uninsured) and the independent variables was tested via multiple logistic regression models adjusted for confounders, with the odds ratio (OR) calculated to a 95% confidence interval (95% CI). Model diagnostic tests were conducted using the Hosmer-Lemeshow goodness of fit test and the analysis of extreme values.

Poisson regression models with robust variance were also estimated in order to ascertain whether having health insurance was associated with the number of doctor and dentist visits, age, and sex, with the variables compared in terms of the rate ratios (RRs) and respective 95% confidence intervals (95% CIs) and values of p≤0.05 considered statistically significant. The analysis was performed using the Stata 15 program (Stata Corp, College Station, TX, USA).

Results

Population characteristics

The mean age of participants was found to be 65.6 (±9.57) years, while 62.7% were female (2,298), 24.6% self-reported a diabetes diagnosis (corresponding to 25.5% of urban inhabitants and 20.6% rural inhabitants), and 78.0% reported fair/poor health status. Approximately 63.8% of participants reported having comorbidities such as high blood pressure, arthritis (13.8%), and impaired vision (53.4%). Approximately 93.3% had visited a doctor in the last year and 40.6% had visited a dentist, while 20.3% self-medicated.

The percentage of adults ≥ 70 years old was higher in the insured group than the uninsured group (39.7% vs 30.6; p<0.001), while the percentage of doctor visits was higher among the insured group than the uninsured group (94.6% vs 90.9%; p<0.001) and self-medication was lower among the insured group than the uninsured group (19.1% vs 22.8%; p=0.008). The results for the sample population are presented in Table 1.

Table 1.

Associations of characteristics between insured and uninsured older 50 adults with diabetes in Mexico (n=3,667)

	Uninsured n=1,253	Insured n=2,414	Value p
Sex
Male	427 (34.1)	942 (39.0)	0.003
Female	826 (65.9)	1472 (61.0)
Age groups
50–59 years	472 (37.7)	673 (27.9)	<0.001
60–69 years	398 (31.8)	782 (32.4)
≥70 years	383 (30.5)	959 (39.7)
Residence
Urban	869 (69.4)	2192 (90.8)	<0.001
Rural	384 (30.6)	222 (9.2)
Years of education
< 9 years	1011 (80.7)	1547 (64.1)	<0.001
≥ 9 years	242 (19.3)	867 (35.9)
Would you say your health is…
Excellent/Very good	21 (1.7)	74 (3.1)	<0.001
Good	210 (16.8)	500 (20.7)
Fair	770 (61.4)	1478 (61.2)
Poor	252 (20.1)	362 (15.0)
Comparing your health now with your health two years ago, would you say your health now is…?
Much better/Somewhat better	165 (13.2)	339 (14.0)	<0.001
More or less the same	558 (44.5)	1226 (50.8)
Somewhat worse	435 (34.7)	726 (30.1)
Much worse	95 (7.6)	123 (5.1)
Visited doctor
No	114 (9.1)	131 (5.4)	<0.001
Yes	1139 (90.9)	2283 (94.6)
Visited dentist
No	834 (66.6)	1346 (55.8)	<0.001
Yes	419 (33.4)	1068 (44.2)
Self-medicated
No	969 (77.3)	1954 (80.9)	0.010
Yes	284 (22.7)	460 (19.1)

Table 2 shows the relationship between the data generated in response to MHAS-2018 questions and health insurance coverage (insured/uninsured), with no statistically significant differences found between oral medication consumption (p=0.242) and a special diet for diabetes control (p=0.491) and health insurance coverage (insured/uninsured). Insured subjects had their diabetes more under control than uninsured subjects (91.7% vs 87.9%; p<0.001, respectively).

Table 2.

Associations between MHAS 2018 questions by insured and uninsured older 50 adults with diabetes in Mexico (n=3,667)

	Uninsured n=1,253	Insured n=2,414	Value p
Are you currently taking any oral medication in order to control your diabetes?
No	133 (10.6)	227 (9.4)	0.242
Yes	1120 (89.4)	2187 (90.6)
Are you currently using insulin shots?
No	999 (79.7)	1737 (72.0)	<0.001
Yes	254 (20.3)	677 (28.0)
Do you follow a special diet to control your diabetes?
No	525 (41.9)	983 (40.7)	0.491
Yes	728 (58.1)	1431 (59.3)
In general, is your diabetes under control now?
No	152 (12.1)	200 (8.3)	<0.001
Yes	1101 (87.9)	2214 (91.7)
How frequently do you measure your blood sugar level or urine-sugar level? (Number of times)
0 times	58 (4.6)	74 (3.1)	0.003
1–3 times	1022 (81.6)	1926 (79.8)
≥ 4 times	173 (13.8)	414 (17.1)

The results of the logistic regression analysis show that having health insurance is positively associated with age and doctor and dentist visits and is negatively associated with type of residence and self-medication, with the corresponding results shown in Table 3. As a result, insured adults are 75% (OR=1.75 [1.32 – 2.31]; p<0.001) more likely to have visited a doctor and 57% more likely to have visited a dentist (OR=1.57 [1.35 – 1.83; p<0.001) than uninsured adults. Similarly, insured adults are 20% less likely (OR=0.80 [0.68 – 0.96]; p=0.017) to self-medicate than uninsured adults, while adults living in rural areas are 77% less likely to be insured than adults living in urban environments.

Table 3.

Adjusted odds ratios from the logistic regression model between insured and uninsured older 50 adults with diabetes in Mexico (n=3,667).

Variables	Crude Odds Ratio (95%CI) *	p	Adjust Odds Ratio (95%CI) *	p
Age†
60 – 69 years	1.37 (1.16 – 1.63)	<0.001	1.46 (1.22 – 1.74)	<0.001
≥ 70 years	1.75 (1.48 – 2.07)	<0.001	1.83 (1.53 – 2.19)	<0.001
Sex‡	0.80 (0.70 – 0.93)	0.003	0.82 (0.70 – 0.95)	0.011
Visited doctor¶	1.74 (1.34 – 2.26)	<0.001	1.75 (1.32 – 2.31)	<0.001
Visited dentist§	1.56 (1.35 – 1.80)	<0.001	1.57 (1.35 – 1.83)	<0.001
Residence•	0.22 (0.19 – 0.27)	<0.001	0.23 (0.20 – 0.28)	<0.001
Self-medication∞	0.79 (0.67 – 0.94)	0.008	0.80 (0.68 – 0.96)	0.017

^*OR= Odds ratio; CI= Confidence Interval.

Reference group: Age^† = group 50–59 years, Sex^‡= Male, visited doctor^¶= No, Visited dentist^§ =No, Residence^•= Urban, Self-medication^∞= No.

Log likelihood = −2162.6996, Hosmer-Lemeshow= 0.729

The results of the application of the Poisson model show that health insurance coverage is positively associated with doctor and dentist visits, while only years of education (≥9 years) is associated with dentist visits. After adjusting the models for age and sex, insured adults were found to be positively and significantly associated with increased doctor and dentist visits [RR=1.32 (1.28 – 1.35); p<0.001] and [RR= 1.47 (1.37 – 1.58); p<0.001, respectively], in contrast with uninsured adults. Moreover, adults with years of education ≥9 were positively and significantly associated with increased dentist visits [RR=1.52 (1.43 – 1.63); p<0.001] (Table 4).

Table 4.

Adjusted rate ratio (RR) from Poisson regression analysis of the number of visits to the doctor and dentist of uninsured and insured older 50 adults with diabetes in Mexico (n=3,667).

		Number of visited doctor	Number of visited dentist
		Robust RR (95% CI)
Health insurance coverage	Uninsured	1.00	1.00
	Insured	1.32 (1.28 – 1.35) p<0.001	1.47 (1.37 – 1.58) p<0.001
Sex	Male	1.00	1.00
	Female	1.19 (1.16 – 1.22) p<0.001	1.12 (1.05 – 1.19) p<0.001
Age	50 – 59 years	1.00	1.00
	60 – 69 years	1.12 (1.09 – 1.16) p<0.001	0.81 (0.76 – 0.88) p<0.001
	≥ 70 years	1.15 (1.12 – 1.19) p<0.001	0.56 (0.52 – 0.61) p<0.001
Years of education	< 9 years	1.00	1.00
	≥ 9 years	1.00 (0.97 – 1.02) p=0.880	1.52 (1.43 – 1.63) p<0.001

RR: Rate Ratio, CI: Confidence Interval.

Discussion

The present study, using data from a nationally representative sample of Mexican adults with diabetes aged 50 years and older, found that doctor and dentist visits were positively associated with the group of insured adults, in contrast with the group of uninsured adults, while a negative association with self-medication was also found.

Pagán JA et al., using a representative sample of diabetic adults from MHAS-2001, found that health coverage was positively associated with access to medical care and negatively associated with self-medication,⁵ results similar to those found in the present study.

For decades, the health care system in Mexico has continued to make efforts to increase access to healthcare services both for those in the population with health insurance coverage from the corresponding public institutions and those without any health insurance coverage. According to research carried out based on information taken from the Mexican Health and Aging Study, differences have been found in the level of use of healthcare services; therefore, older adults with social security coverage have better access to health services than the uninsured population.^16,17 The present study, conducted with information taken from MHAS-2018, found that 65.8% of diabetic adults aged 50 and over had health insurance coverage.

The present study also found that living in a rural area makes access to healthcare coverage less likely, with inequality and population dispersion affecting access to health services in Mexico, with the latter variable originating in economic, geographic, ethnic, cultural, social, and labor factors.⁹ Gutiérrez JP analyzed information taken from ENSANUT-2006 and 2012, which used indicators of effective coverage for preventive and basic care interventions, and found that, while health protection has improved significantly, health disparities by socioeconomic level continue.¹⁸ Therefore, it is important that healthcare systems help to reverse health inequality by guaranteeing equal access to quality healthcare for the entire population.

Public health policies have been developed and implemented in Mexico with the objective of expanding health coverage and providing financial protection to those in the population without social security coverage, thus ensuring their access to healthcare services. One of these policies was the implementation of the SP program,¹⁹ which was reformed in 2019, becoming the INSABI and will cover the 69 million Mexicans who do not have access to health insurance coverage via IMSS, ISSSTE, SEDENA, and SEMAR.

The goal set for INSABI is to provide free universal health care and address the gaps in both health coverage between urban and rural areas and the availability of doctors and nurses in Mexico’s most remote and marginalized regions. In addition, INSABI could have a huge impact on family wellbeing, especially for those with members presenting chronic conditions such as diabetes and hypertension and that through their out-of-pocket expenses they cover just over half of the total cost of care for these diseases.²⁰

INSABI aims to provide benefits between the insured and the uninsured and where the federal government will be the sole funder and provider of coverage for the uninsured.²¹ With INSABI, it is expected to have greater universal health coverage throughout the country, reducing catastrophic expenses and increasing the coverage of high-cost interventions.²²

Likewise, INSABI could have a great positive impact on the main public health challenges, such as reducing the main causes of morbidity and mortality that need to be addressed, for example, diabetes and obesity, which are chronic diseases with the highest prevalence and affect a large part of the Mexican population, in 2017 Mexico was among the five countries with the highest prevalence of diabetes (13.1 million) and deaths (64,067).²³ Also, in reducing social and health inequalities, giving total priority to meeting the main health needs of the population in the country. Therefore, with this set of previously mentioned actions, they could reduce the prevalence and risks associated with diabetes and obesity, in addition to preventing damage to health and contributing to the decrease in mortality.

The present study found that the insured group reported 1.47 (p<0.001) more dentist visits than the uninsured (44.2% vs 33.4%; p<0.001). Various studies have found that people with diabetes experience a higher frequency of oral complications, such as dental caries (50%)²⁴, xerostomia (30%)²⁵, tooth loss (80%)²⁶, and periodontal disease (80–90%).²⁷ Additionally, it has been noted that the risk of periodontitis is higher in people with diabetes than in those without the disease.²⁸

Research has shown that patients with diabetes are less likely to visit the dentist than those without diabetes.²⁹ Tomar et al., in a study comparing dental visits made by adults with and without diabetes in the United States, found that adults with diabetes were less likely to have seen a dentist than those without diabetes (65.8% vs 73.1%, p<0.0001),³⁰ while Macek et al. found that the presence of diabetes was significantly associated with dental visits.³¹

As diabetes is associated with a wide range of adverse effects on both oral and general health, adults with diabetes who visit the dentist more often may benefit from improving their oral health and decreasing the prevalence of oral diseases such as periodontitis.

The present study found that the prevalence of self-reported diabetes in the population aged 50 years and over was found to be 24.6% higher than the 21.4% reported by the MHAS-2012 survey³² and the 16.0%% reported by the MHAS-2001.⁵ According to data taken from ENSANUT-2018, diabetes currently affects 8.6 million people in Mexico.³ The increased prevalence of diabetes reported by MHAS may be due to an increasingly ageing population, the increased prevalence of overweight and obesity related to lifestyle changes (increased dietary caloric density and reduced physical activity), and changes in other diabetes-related factors.³³

Finally, health insurance coverage in the population could play an important role in the management of diabetes, which is a chronic multi-cause disease. Among the main findings of the present study, being insured was found to be positively associated with doctor and dentist visits, an important association, as diabetes must be carefully monitored and controlled to reduce complications, economic cost, and the loss of quality of life for those with diabetes and their families.

Conclusions

The present research found a positive association between doctor and dental visits in the insured diabetic population aged 50 and over in Mexico. Self-medication was lower in the insured population than in the uninsured population. A major public health challenge in Mexico is the number of diabetics who report being uninsured, requiring that healthcare coverage be extended to this population to ensure the necessary follow-up and control to prevent clinical complications. In addition, this requires the generation of strategies that have a positive impact on the quality of the healthcare process, help to improve adherence to treatment, and, thus, lead to substantial improvements in health outcomes.