Many Americans travel south to Mexico for cheaper medical care, but how does the Mexican healthcare system work for its most vulnerable citizens?

As U.S. politicians continue to battle over healthcare plans, some medical tourism experts are predicting an increase in Americans traveling to Mexico in search of affordable medical and dental care.

Especially if the Affordable Care Act is repealed.

This trend, though, is not new.

Even as more Americans gained health insurance under Obamacare, many people found that in some cases it was cheaper to pay out-of-pocket for care south of the border.

That says something about the Mexican healthcare system.

It also says a lot about the United States, which struggles with rising healthcare costs and a steadily shifting insurance marketplace.

But this is only part of the story.

Mexico has a mix of public health insurance programs, employer-provided health insurance and private out-of-pocket care. And a number of disconnected social security institutes that provide care.

That means Americans traveling to Mexico may only be experiencing one aspect of the country’s healthcare system.

So how do Mexicans living in poverty or just above the poverty line fare under the country’s relatively new universal health coverage?

The World Health Organization (WHO) defines universal health coverage as a program that ensures all people in a country receive the high-quality health services they need — without suffering financially as a result.

This includes providing people with a full range of health services, including prevention, treatment, rehabilitation, and palliative care.

However, it doesn’t mean that every possible health service is free to everyone. That kind of system is unsustainable.

And a “universal” approach doesn’t necessarily have to be a single-payer system like those found in countries like the United Kingdom and Canada, or the kind proposed by some Democrats in the United States.

Part of Mexico’s approach to universal health coverage was the introduction of the Seguro Popular (Popular Health Insurance) program more than 10 years ago.

This was meant to improve access for poor families to health services, and prevent them from suffering financially due to illness.

According to the World Bank, before this program only about half of Mexicans carried health insurance, mainly through their employers.

Low income families without insurance paid for much of their healthcare out-of-pocket. Public health programs existed, but there was no essential set of free health services for this segment of the population.

Seguro Popular provides unemployed and poor Mexicans with access to preventative healthcare services such as diabetes screening and vaccinations, as well as treatment for chronic and severe illnesses.

Enrollees don’t have to pay a fee at the time of the doctor visit.

The program is supported by a mix of federal and state funds — similar to how the Medicaid program for low-income Americans is funded.

The poorest families pay nothing to join Seguro Popular. The rest pay a premium based on their income.

By 2013, the number of enrollees in Seguro Popular had grown to 55 million — helping the country achieve universal health coverage.

This is roughly the same number of Americans who were enrolled in Medicaid before states expanded the program under Obamacare. That number is currently 74 million.

Obamacare — including the Medicaid expansion — was supposed to reduce the number of uninsured in the United States.

It did, but last year’s record low was still 28 million uninsured, according to the Centers for Disease Control and Prevention (CDC).

Research shows that since the introduction of Seguro Popular in Mexico, some aspects of the country’s health has improved.

A study published this year in The Lancet found that Mexico’s Healthcare Access and Quality Index rating rose from 49.2 in 1990 to 62.6 in 2015.

This 100-point scale is a measure of citizens’ access to quality healthcare. It is based on the death rates for 32 diseases that can usually be treated easily, including heart disease, diabetes, maternal and infant diseases, as well as diseases that can be prevented with vaccinations.

Over the same period, the HAQ Index for the United States rose from 73.7 to 81.3.

The average for all countries was 53.7 in 2015. Andorra topped the list that year at 94.6, with Afghanistan and Papua New Guinea at the low end.

A report last year by the Organisation for Economic Cooperation and Development (OECD) highlighted some of the specific successes of the Mexican healthcare system and also areas that still need work.

In the past 10 years, the number of Mexicans who experienced “impoverishing” health care costs fell from 3.3 percent to 0.8 percent.

A similar rating isn’t listed for the United States. But a CDC survey found that in 2016, 16 percent of Americans under 65 years old were parts of families that had trouble paying their medical bills.

Between 2000 and 2013, infant mortality in Mexico also dropped, falling 38 percent to 13 deaths per 1,000 live births.

In 2015, the U.S. infant mortality rate was 5.9 deaths per live births, according to the CDC.

Another OECD report found that deaths from heart disease and stroke in Mexico have declined, as well — now at 292 deaths per 100,000 people.

In 2014, 252 out of every 100,000 Americans died from cardiovascular diseases, according to a study in the Journal of the American Medical Association (JAMA). This is a 50 percent decline since 1980, but these diseases are still the leading cause of death in the United States.

In spite of its gains in some areas, Mexico still struggles with other health-related issues.

The country has the second highest rate of adult obesity after the United States. And the situation is worsening.

In 2012, 71 percent of Mexicans were overweight or obese, according to the OECD report — up from 62 percent in 2000.

In the United States, more than 70 percent of Americans are overweight or obese.

Diabetes is also common among Mexicans — 16 percent of adults.

In the United States the CDC lists the adult diabetes rate as 9 percent.

The persistence of these and other diseases has increased the life expectancy gap between Mexico and other OECD countries from four years to six years. Mexicans born in 2013 can expect to live to be 74 years old on average.

Life expectancy at birth in the United States is 78 years.

In spite of Mexico’s success in achieving universal health coverage, the OECD report outlines several areas that still need improvement.

One problem is that care is provided by a number of social security institutes that are not connected. If Mexicans lose their jobs, they may have to switch doctors, which disrupts the continuity of their care.

This also happens in the United States, where private health insurance — as well as Medicare and Medicaid — have preferred provider networks. If you switch insurance, you may either have to switch doctors or pay more to keep going to the one you’ve had for years.

Mexico’s investment in its healthcare system is also on the low side, although it is increasing. In 2014 Mexico spent 3.3 percent of its gross domestic product (GDP) on healthcare, up from 2.4 percent in 2003.

In 2015, the United States spent 17 percent of its GDP on healthcare, according to the Centers for Medicare and Medicaid Services (CMS). Medicaid accounted for 17 percent of this total.

More money, though, doesn’t always mean better results.

The United States spends more per person on healthcare than every other country in the world, but it still has a lower life expectancy than some lower-spending countries.

Even with the introduction of Seguro Popular, the OECD reports that overall out-of-pocket spending on health services in Mexico remains high — 45 percent. For families, this translates to 4 percent of their household expenses.

CMS reports that overall, Americans pay only 11 percent out-of-pocket. But healthcare costs in the United States are higher than in Mexico, which is one reason Americans continue to cross the border for medical care.

In spite of the work that still needs to be done to improve the Mexican healthcare system, some recent research suggests that Seguro Popular is achieving some of its goals.

A study published in The Lancet earlier this year found that Seguro Popular reduced catastrophic spending on health services — more than 30 percent of household income — by 23 percent among enrollees. The effect was stronger for poorer households.

The program also reduced out-of-pocket spending for inpatient and outpatient medical care, both overall and for poor families.

However, there was no reduced out-of-pocket spending on medication or medical devices.

Almost 70 percent of enrollees rated the quality of the health services they received as “very good or good.”

A recent survey in JAMA Internal Medicine found that 46 percent of Medicaid enrollees rated the program 9 or 10 on a 10-point scale. Overall they rated the program 7.9.

Many Americans traveling to Mexico for medical care are pleased with the care they receive — and the lower cost compared with care back home. But their experiences may not reflect the situation for all Mexicans.

There continues to be differences in the healthcare received by different groups in Mexico — such as for people in rural vs urban areas, or household income and wealth.

The United States, even with its high spending on healthcare, is not immune from these kinds of health disparities.

A 2017 study in Health Affairs found that 38 percent of the poorest third of Americans reported being in “fair or poor” health. For the richest third, it was 12 percent.

Chile and Portugal were the only two countries with a larger income-based gap in the health of their citizens.

Mexico was not included in this study. But the results show that spending more on healthcare is no guarantee that everyone in the country will fare equally well.

Still, even as debates over healthcare continue in the United States, Mexico is already into its second decade of universal healthcare.