Why does bone density not change much despite regular anti-osteoporosis treatment? What can we do?

Author: Guo Shuzhang, Chief Physician of Tianjin Third Central Hospital

Reviewer: Tian Yonggang, Chief Physician, Tianjin Third Central Hospital

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A 70-year-old woman named Chen came to the clinic. She was diagnosed with osteoporosis two years ago and has been taking calcium tablets, calcitriol and anti-osteoporosis drugs regularly and systematically. She also has her bone density checked once a year. It was time for another checkup and she came on time. The result showed that her bone density T value was -2.8.

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The first time (the year before last) the T value was -3.0, and last year it was -2.9. Aunt Chen was very upset and puzzled: after two years of treatment, she also strictly followed the doctor's instructions to take the medicine, why did the bone density not change much?

Aunt Chen felt that the treatment was not effective and that it was meaningless to continue like this, so she lost confidence in the treatment. After questioning, the outpatient doctor found that Aunt Chen's symptoms of body pain, muscle cramps, and fatigue had been significantly alleviated, but her bone density had not changed much.

Many patients have encountered this situation, which is very confusing and a common misunderstanding: people always think that after taking anti-osteoporosis drugs and supplementing with vitamin D and calcium, bone density will return to normal, just like taking antihypertensive drugs will maintain normal blood pressure, or taking hypoglycemic drugs will lower blood sugar.

But the fact is: existing therapeutic drugs can only change bone density to a very small extent, and bone density is difficult to restore to normal. Effective treatment is to stop it from declining or to slow down the rate of decline.

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Drug treatments for osteoporosis include the use of calcium supplements, vitamin D, and anti-osteoporosis drugs. Calcium supplementation can slow bone loss and improve bone mineralization; vitamin D, especially active vitamin D, can promote calcium absorption, maintain muscle strength, maintain body stability, and reduce the risk of fractures. However, neither of them, whether used alone or in combination, can increase bone density. Only the combined use of anti-osteoporosis drugs can increase bone mass and quality. However, the existing anti-osteoporosis drugs have very limited effects on improving bone density in the short term. Studies have reported that even with regular anti-osteoporosis treatment, the annual change in bone density in the human body is only about 5%.

Since the change in bone density is so small, why use these drugs?

The purpose of using anti-osteoporosis drugs is to minimize bone loss, relieve the associated discomfort symptoms caused by osteoporosis, and reduce the incidence of spinal fractures or hip fractures.

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As we all know, osteoporosis is characterized by decreased bone strength and increased risk of fractures, and the greatest hazard and ultimate event is fracture. Clinically, bone density measurement is still used as an indicator for diagnosing osteoporosis and evaluating drug efficacy, but it is not the only indicator. The efficacy of anti-osteoporosis drugs can be evaluated based on the degree of symptom relief and the impact on the incidence of osteoporotic fractures. Research data show that, in general, anti-osteoporosis drugs can reduce the incidence of spinal fractures or hip fractures by 30% to 50%. Another evaluation indicator is to measure the level of serum bone turnover markers. Bone turnover markers can be divided into bone resorption markers (such as type I collagen cross-linked carboxyl terminal peptide) and bone formation markers (such as total type I collagen amino terminal propeptide). In clinical practice, bone turnover markers are detected to indirectly reflect the metabolic rate of bones. Generally speaking, if the level of serum bone turnover markers decreases, it means that the treatment is effective.

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To sum up: for patients who have been diagnosed with osteoporosis, they should adhere to a healthy lifestyle, eat a reasonable and balanced diet, receive regular anti-osteoporosis treatment, be careful to prevent fractures, and pay appropriate attention to changes in bone density. However, there is no need to worry about small changes in bone density. It is best to have a doctor make a comprehensive judgment and interpretation, and guide the next treatment plan.