How to prevent osteoporosis with Unfractionated Heparin (UFH)?

From the Guidelines

To prevent osteoporosis when using unfractionated heparin, it is crucial to consider alternative anticoagulants like low molecular weight heparin (LMWH) which have a lower risk of osteoporosis, as evidenced by the American College of Chest Physicians guidelines 1. When unfractionated heparin (UFH) is necessary, several measures can be taken to mitigate the risk of osteoporosis. These include:

• Supplementing with calcium (1000-1500 mg daily) and vitamin D (800-1000 IU daily) to support bone health, especially for long-term therapy exceeding 3 months.
• Considering the addition of bisphosphonates like alendronate (70 mg weekly) or risedronate (35 mg weekly) for high-risk patients, particularly postmenopausal women or those requiring prolonged heparin treatment.
• Encouraging regular weight-bearing exercise (30 minutes daily) to help maintain bone density.
• Monitoring bone mineral density with DEXA scans before starting therapy and periodically thereafter to assess the need for intervention. The rationale behind these recommendations stems from the understanding that UFH can inhibit osteoblast formation and promote bone resorption by increasing osteoclast activity, leading to significant bone loss, especially with doses exceeding 15,000 units daily for more than 3-6 months, as described in the context of parenteral anticoagulants 1. Given the potential for heparin-induced bone loss to begin within weeks of starting therapy, early intervention is paramount.

From the Research

Prevention of Osteoporosis with Unfractionated Heparin

• Unfractionated heparin can lead to osteoporosis as a complication of prolonged treatment, and the risk is probably multifactorial 2.
• The mechanism of heparin-induced osteoporosis can be explained by the effect of heparin as a cofactor for physiological stimulators of osteoclasts 3.
• Prevention of osteoporosis in patients treated with unfractionated heparin includes screening for patients at risk, preferential use of low-molecular weight heparins, early switch to anti-vitamin K, and vitamin and calcium supplementation in pregnant women and elderly subjects 3.
• Curative treatment of heparin-induced osteoporosis combines vitamin-calcium supplementation with inhibitors of bone resorption 3.
• Bisphosphonates can be used for the prevention and treatment of osteoporosis, as they reduce the risk of fracture by suppressing bone resorption and increasing bone strength 4.
• Adequate intake of calcium and vitamin D, avoidance of smoking and excessive alcohol intake, weight-bearing and resistance-training exercise, and fall prevention are also important for fracture prevention 5.

Risk Factors and Monitoring

• Long-term exposure to unfractionated heparin can cause a modest but progressive decrease in bone mineral density (BMD), and it is more evident in patients on low-molecular weight heparins than on acenocoumarol 2.
• Patients with concomitant risk factors for osteoporosis should be monitored closely, and densitometry should be performed before starting long-term anticoagulation and repeated every 12 months 2.
• The use of anticoagulants, including unfractionated heparin, should be cautious in subjects at risk of osteoporosis, and literature supports a detrimental effect of heparin on bone, with an increase in fracture rate 6.