Bariatric patients more likely to have non-typical osteoporotic site fractures

Bariatric surgery patients are more likely to have more non-typical osteoporotic site fractures affecting mainly feet and hands, and fractures tend to occur earlier, compared to patients on medical weight management programme (control group). The findings were reported in the paper, ‘Increased Fracture Risk After Bariatric Surgery: a Case-Controlled Study with a Long-Term Follow-Up’, published in Obesity Surgery, by researchers from the Hamad Medical Corporation, Doha, Qatar.

The loss of bone mineral content after malabsorptive bariatric surgery has been reported in the medical literature, however, the paper’s authors noted that this has barely been reported in Middle East countries. They stated that this is particularly relevant due to the high prevalence of vitamin D insufficiency in the region. Therefore, the designed a study to examine whether bariatric surgery increases the risk of fracture in patients who had surgery. The selected surgery cases were then matched with non-surgical weight reduction management controls and followed in the same bariatric clinics. Both groups were followed retrospectively until January 2020 for fracture events (documented by a radiologist).


In total, 403 surgical patients were matched to 806 controls with a mean (SD) follow-up for both groups of 8.07+0.023 years. Median age was 36.0 years for surgical group vs 37.0 years for the control group (p=0.13). The surgical group had a significantly higher baseline median BMI46.93 vs the control group (BMI35.49). The surgical group had a higher pre-index date fracture rate (5% vs 1%), proton pump inhibitor use (41.2% vs 11.9%), primary hyperparathyroidism (0.7% vs 0.0%) and inflammatory bowel disease (0.5% vs 0.0%) vs the control group. The vast majority of patients (87%) has a sleeve gastrectomy (gastric bypass, 17%).


Outcomes

The authors reported that fracture events were significantly higher in the surgical group (38 or 9.4%) vs the controls group (28 or 3.5%), with more fractures in females (p=0.299). In addition, fractures occurred at a younger age in the surgical group as compared with controls (median IQR age at the time of the fracture was 36.0 ∓ 14 years in the surgical group and 37 ∓ 14 in controls, p=0.013). Although the baseline BMI was significantly higher in the surgical group, the BMI at the time of the fractures was not significantly different between the two groups (p=0.763). There was no statistically significant difference in the site of the fractures in the two groups. The time for the highest hazard risk ratio for fracture post-bariatric surgery in comparison with the non-surgical group was around year six.


They also reported that the factors that were significantly associated with the cases of fracture included:

  • age group at a cut-off point of 40 years old (p=0.038), patients who went through the surgery has almost three times more likely to experience a fracture.

  • the surgical group (p<0.0001) if the patient is taking proton pump inhibitor (p = 0.001), patients were around two times more likely to experience a fracture, but PPI was not a risk factor for fracture.

  • antiepileptic medication (p<0.0001), patients were around eight times more likely to experience a fracture.

  • baseline BMI level ≥ 35 (p=0.001) and;

  • baseline BMI level ≥ 40 (p=0.001)

Firstly, we would like to point to the fact that our study had the highest period for post-bariatric surgical follow up of 8.6 years among the other published studies. In this single-centre case–control study, the risk of fracture in patients with obesity who underwent bariatric surgical intervention, mainly sleeve gastrectomy, was significantly higher at 2.7-folds comparing with age and gender-matched patients with obesity managed with weight reduction therapy. Nevertheless, the vast majority of the fractures were not typical for osteoporotic fragility fracture in both groups.


“Our study was the first study that delineates fracture risk post-bariatric procedure in the Middle Eastern population. The mean duration of follow-up is the longest as compared with previous studies and hence the highest risk for fracture,” they concluded. “We also founded the possible confounders, which should be considered in any future study in this field. Suitable intervention is needed to ameliorate the high risk in the surgical intervention group.”


Further information

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