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Impact of Weight Loss On Bone Fracture In Patients with Type 2 Diabetes

Apr 7, 2018
 

Study shows greater than 20% weight decrease, especially in men, can significantly increase risk of fragility fractures.

Studies have shown that patients with type 2 diabetes have a higher risk of bone fracture compared to the population without diabetes. Hip and spine fractures have increased risk of mortality associated with it. Therefore, the prevention of fractures may prolong life expectancy of patients with diabetes. Although the mechanism by which bone fractures are caused is yet to be understood, some of the proposed theories include decreased bone turnover, oxidative stress, certain diabetes medications, and glycation of collagen. Moreover, patients with type 2 diabetes have increased tendency of weight loss, possibly due to some diabetes medications such as sodium-glucose cotransporter 2 inhibitors and glucagon-like peptide 1 receptor agonists, or treatment of obesity, or insulin deficiency. Weight loss is significantly associated with an increased fracture risk. Weight loss decreased bone mineral density in patients with type 2 diabetes. This study examined the relationship between body weight loss and fracture risk in Japanese patients with type 2 diabetes.

A total of 4,758 Japanese patients age 20 years and older with type 2 diabetes were studied between April 2008 and October 2010. The following patient population was excluded from the study: if they had drug-induced diabetes or if they were using corticosteroids, patients undergoing renal replacement therapy, patients with serious diseases other than diabetes, and patients who were not able to visit diabetologists regularly. Patients’ body weight loss was categorized into four groups: <10%, 10% – 20%, 20 – 30% and ≥ 30%. Patients’ history of any fractures was obtained at enrolment and any further fractures during the study period were assessed using a self-administered questionnaire. This study focused on the risks of fragility fractures (hip and spine sites) because fragility fractures are associated with increased mortality risk. The primary outcome of this study was first fragility fracture and secondary outcome was first fracture at any site. The follow-up period was calculated as the time from enrollment to the first fracture, death, or study ending date, whichever happened first.

The results of this study found that fragility fractures and cancer risk increased significantly in patients with greater body weight loss. On the other hand, HbA1c and use of pioglitazone and antihypertension drug use decreased significantly with greater body weight loss. From the start to the end of the study period, about 198 participants sustained fragility fractures with 54 of these being hip and 144 of these being spine fracture. Overall, men had significantly higher fragility fractures than women (p < 0.001).

As per secondary outcome, 662 participants sustained fractures at other sites. Out of these, 249 occurred in men and 413 occurred in postmenopausal women. Participants with greater weight loss had significantly higher fractures (p < 0.001). Overall, results for both fragility and other sites fractures showed that there is an association between body weight loss and bone fractures in men but not in postmenopausal women.

In conclusion, this study found that in patients with type 2 diabetes, greater body weight loss was significantly associated with increased risk of fragility fractures. This association was stronger in men than in postmenopausal women. This can be explained by the fact that men lose more muscle mass than women, which increases stress on the bone. Also, changes in sex hormones in postmenopausal women can also explain this finding.

The mechanism by which body weight loss may influence fracture risk can be explained by few explanations. First, body weight loss decreases bone mineral density in both the general patient population and patients with type 2 diabetes. Secondly, body weight loss results in decreased muscle strength and decreased physical activity. This increases the overall risk of fall. Thirdly, many patients with diabetes have obesity or are trying to control their diet for blood glucose control. The changes in diet can lead to decreased intake of crucial nutrients such as protein, vitamin D, and calcium, which are very important for bone strength. Finally, other studies have explained that fracture risk can be higher due to body weight loss from other serious medical conditions like cancer. Because this study showed that greater body weight loss increases risk of fractures in patients with type 2 diabetes, preventive measures should be taken into consideration in patients who lose greater than 20% of the body weight.

Practice Pearls:

  • Results of this study show that greater than 20% body weight loss can significantly increase the risk of fragility fractures in patients with  type 2 diabetes.
  • The association of weight loss with fracture risk was stronger in men than in postmenopausal women.
  • Preventive measures should be done to prevent fractures in patients with significant weight loss and type 2 diabetes.

Reference:

Komorita Y, Iwase M, Fujii H et al. Impact of body weight loss from maximum weight on fragility bone fractures in Japanese patients with type 2 diabetes: the Fukuoka Diabetes Registry. Diabetes Care. March 2018.

Vidhi Patel, Pharm. D. Candidate 2018, LECOM School of Pharmacy