The prevalence of osteoporosis, which occurs mainly in the elderly, is rising with the Korean population's rapid aging. About 1.08 million Koreans suffered from osteoporosis in 2019, up about 250,000 from five years ago.

Osteoporotic fractures are a serious contributor to the increased risk of death in seniors. Among elderly osteoporotic patients, only 80 percent of those who have broken major parts of the body, such as the spine and femur, survive for five years or longer.

Professor Kim Hak-sun at Gangnam Severance Hospital is an eminent orthopedic spine surgeon who has been treating severe osteoporosis for 25 years.

Korea Biomedical Review has met him to hear about the risk of osteoporotic fractures and his treatment know-how for patients with severe osteoporosis.

Professor Kim Hak-sun at the Orthopedic Spine Surgery Department of Gangnam Severance Hospital speaks during an interview with Korea Biomedical Review.
Professor Kim Hak-sun at the Orthopedic Spine Surgery Department of Gangnam Severance Hospital speaks during an interview with Korea Biomedical Review.

Question: How dangerous is a fracture in osteoporosis patients? Why are treatment and management important?

Answer: One in four osteoporosis patients who have experienced a broken bone suffers a fracture recurrence within four years. A follow-up analysis of 135,273 osteoporosis patients showed that 10,000 patients suffered 2,481 recurrence cases within four years.

As a person treating severe osteoporosis patients, I found it not uncommon to witness a fractured patient's death. In the early days of treatment in 1995, hospitalized patients with osteoporotic fractures died within two months because we did not have effective therapies. Treatment of severe osteoporosis is directly related to patients’ survival. So, I’m using effective injections for severe osteoporosis rather than oral drugs used in chronic patients.

Q: What is the most important aspect when treating patients with severe osteoporosis?

A: In treating severe osteoporosis, it is important to consider three things together: preventing additional fractures, reducing pain, and using appropriate treatments.

People have a common misconception about osteoporosis. They tend to think that exercise will be helpful to cure osteoporosis. However, if a patient with a high risk of fracture exercises, he or she can have additional fractures easily. So, what’s most appropriate in osteoporosis treatment is to use adequate drugs.

Q: What are your criteria for choosing a treatment among various options?

A: I set the grade from Grade 1 to Grade 4, using higher grade drugs for less severe patients. Grade 1 drugs are parathyroid hormones (PTH) such as teriparatide and romosozumab. The two agents stimulate bone formation. Grade 2 includes denosumab, a therapy targeting RANK that is injected once every six months. In Grade 3, I use bisphosphonate class drugs such as alendronic acid or ibandronic acid. Grade 4 treatments are old ones like calcitonin. I mainly use Grade 1 and Grade 2 therapies for severe osteoporosis.

Q: Do you think that bone formation drugs are more effective than bone resorption inhibitors in the short term?

A: With my personal experiences, I can tell you that the use of Grade 1 drugs (for bone formation) for just four or five months can be remarkably effective. The use of bone formation drugs in Grade 1 reduced the number of recurrent fracture cases in Grade 2 to one or two from hundreds. Although some related papers have been published, this has not been accepted as an evidence-based therapy. However, I am building data myself.

I make sure that patients get osteogenesis promoting drugs for at least three months to six months, specifically. When administered for about three months, they often improve patients’ pain considerably. After that, I usually use bone resorption inhibitors. One bone resorption inhibitor can be injected once every six months, which makes patient compliance excellent. Getting an injection once a month is too frequent because patients have to come to the hospital frequently. An injection every six months is more suitable. But in the first-line treatment, even if patients have to get injections often, I recommend that they get bone formation injections for at least three to six months.

Q: Do you have particular indicators to predict the degree of improvement?

A: I don’t think bone density tests such as T-score are not very reliable. Bone density test results may vary depending on the machine type and the difference in directions and angles. To compare previous data, the patient has to provide the same posture and angle as much as possible. However, as health insurance covers a bone density test, I have my patients take it once a year.

The marker I trust the most is patients’ patient reduction. Secondly, I think the bone marker test is important. Among bone markers, P1NP (serum procollagen type 1 N-terminal propeptide) is a good marker recognized worldwide. Other bone markers include alkali phosphatase (ALP) and osteocalcin.

Q: Do you experience any difficulties in using Grade 1 or 2 injections for severe osteoporosis patients?

A: Denosumab, which is used once every six months, is widely covered by the insurance. So, I can use it as a reimbursable drug for non-severe osteoporosis patients. However, teriparatide among bone formation stimulators can only be used in patients with severe osteoporosis. This drug is reimbursable only for patients with two or more fractures. I have been using teriparatide for around 15 years, and I am totally satisfied with this drug. I am confident that if a patient uses teriparatide as the first treatment for some time and switch to another drug, there will be a good treatment effect.

In terms of price, teriparatide’s price has come down to a reasonable level. It costs a little over 200,000 won ($181) to use it for a month, and I don’t think the drug price is high. As a biosimilar of teriparatide has been released in the market, and the original drug's cost has gone down, I think the government could allow a widened scope of the reimbursement.

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