One controversial election pledge made by President-elect Park Geun-hye is her plan to provide free medical care for four disease groups: cancer, cerebrovascular disorders, heart problems and terminal illnesses.

The scheme, if implemented, would lower the high medical bills of the people suffering from these major diseases. But critics question its wisdom and argue that the money needed to finance it should be used to tackle more serious challenges facing the nation’s health insurance program.

In the first place, they dismiss the cost estimate offered by the ruling Saenuri Party as unrealistic. During the campaign period, the party put the cost at 1.5 trillion won a year for five years from 2013.

But after the election, the state-run Korea Institute for Health and Social Affairs estimated the scheme would cost 5.45 trillion won a year on average during Park’s tenure.

Critics also note that the plan involves serious equity issues as the national health insurance scheme already offers far larger benefits to victims of these four disease groups compared with other patients.

In 2010, the state-run insurance program covered on average 62.7 percent of the medical expenses incurred by its beneficiaries. But the benefit packages for patients with cancer, cerebrovascular diseases and cardiac disorders were generous enough to cover about 80 percent of their medical bills.

In contrast, the benefit levels for certain diseases were disproportionately low ― 7.1 percent for musculoskeletal disorders, 1.1 percent for chronic obstructive lung disease and 1 percent for chronic renal failure.

A more serious problem with the scheme is that it fails to address the most pernicious threat to the financial sustainability of the public health insurance scheme: the surging health care costs for elderly people.

According to the National Health Insurance Corp., the medical bills of senior citizens aged 65 or older totaled 15.4 trillion won in 2011, accounting for one-third of its aggregate benefit payments, which added up to 46.2 trillion won.

The NHIC said medical expenses for aged people had continued to grow by double digits for more than a decade until 2010. The problem is that the growth pace is likely to accelerate in the years to come.

To see what happens when medical bills for seniors soar, one need not look further than Japan. According to news reports, more than 90 percent of the health and welfare cooperatives in Japan are in deficit due to the ballooning medical costs for people aged 75 or older.

Korea seems to be following in Japan’s footsteps. The NHIC has forecast that population aging would swell its deficit from 5.8 trillion won in 2015 to 17.3 trillion won in 2020 and to over 50 trillion won in 2030, even without taking into account Park’s election pledge.

Korea should take a path different from Japan’s. It needs to curb the health care costs for seniors and ensure the sustainability of its health insurance program. For this, the government should start by stepping up efforts toward preventive health care.

In a rapidly aging society like Korea, the occurrences of adult diseases such as diabetes and hypertension increase, driving up health care bills. When it comes to chronic adult diseases, prevention is far more important than treatment.

Nevertheless, the nation’s health care system has been dominated by acute care, neglecting chronic disease preventive care. Spending on prevention by either the government or the NHIC has been negligible.

This does not make sense in this era of increasing chronic diseases. The government needs to shift the focus of health care policy from acute care to preventive care. This is necessary not only to keep the health insurance scheme sustainable but to enhance the health of the population.

Seen in this context, Park’s promise to provide 100 percent coverage for the four disease groups has missed the point. Priority should be placed on building a primary preventive system and expanding public health infrastructure.