Change in fracture risk and fracture pattern after bariatric surgery: nested case-control study

Abstract

Objective To investigate whether bariatric surgery increases the risk of fracture.Design Retrospective nested case-control study.Setting Patients who underwent bariatric surgery in the province of Quebec, Canada, between 2001 and 2014, selected using healthcare administrative databases.Participants 12 676 patients who underwent bariatric surgery, age and sex matched with 38 028 obese and 126 760 non-obese controls.Main outcome measures Incidence and sites of fracture in patients who had undergone bariatric surgery compared with obese and non-obese controls. Fracture risk was also compared before and after surgery (index date) within each group and by type of surgery from 2006 to 2014. Multivariate conditional Poisson regression models were adjusted for fracture history, number of comorbidities, sociomaterial deprivation, and area of residence.Results Before surgery, patients undergoing bariatric surgery (9169 (72.3%) women; mean age 42 (SD 11) years) were more likely to fracture (1326; 10.5%) than were obese (3065; 8.1%) or non-obese (8329; 6.6%) controls. A mean of 4.4 years after surgery, bariatric patients were more susceptible to fracture (514; 4.1%) than were obese (1013; 2.7%) and non-obese (3008; 2.4%) controls. Postoperative adjusted fracture risk was higher in the bariatric group than in the obese (relative risk 1.38, 95% confidence interval 1.23 to 1.55) and non-obese (1.44, 1.29 to 1.59) groups. Before surgery, the risk of distal lower limb fracture was higher, upper limb fracture risk was lower, and risk of clinical spine, hip, femur, or pelvic fractures was similar in the bariatric and obese groups compared with the non-obese group. After surgery, risk of distal lower limb fracture decreased (relative risk 0.66, 0.56 to 0.78), whereas risk of upper limb (1.64, 1.40 to 1.93), clinical spine (1.78, 1.08 to 2.93), pelvic, hip, or femur (2.52, 1.78 to 3.59) fractures increased. The increase in risk of fracture reached significance only for biliopancreatic diversion.Conclusions Patients undergoing bariatric surgery were more likely to have fractures than were obese or non-obese controls, and this risk remained higher after surgery. Fracture risk was site specific, changing from a pattern associated with obesity to a pattern typical of osteoporosis after surgery. Only biliopancreatic diversion was clearly associated with fracture risk; however, results for Roux-en-Y gastric bypass and sleeve gastrectomy remain inconclusive. Fracture risk assessment and management should be part of bariatric care.

Obesity and bone metabolism

“…A study with a mean follow-up of 4.8 years, in which most patients had undergone a restrictive procedure, a 1.21-fold risk of any fracture was observed post-surgery, while there was a trend towards more fractures around 1 to 2 years after the procedure [116]. Another study showed a change in the pattern of fractures post-bariatric surgery, shifting from a pattern typically associated with obesity with a high risk of distal lower limb fractures and lower risk of upper limb fractures to a pattern associated with osteoporosis and more fractures of the upper limb, vertebral pelvic, hip, and femur [118]. A single study did not demonstrate any difference in the rates of fracture between patients who had undergone bariatric surgery and controls; however, in this study, mean follow-up was only 2.2 years [119].…”

“…There are some data concerning the effects of bariatric surgery on fracture risk, with most studies reporting a higher risk of fracture post-surgery [116][117][118]. The type of surgical procedure seems to play a very important role, malabsorptive procedures being associated with a higher risk and restrictive ones having minimal, if any, effect on the risk of fracture [116,118].…”

“…The type of surgical procedure seems to play a very important role, malabsorptive procedures being associated with a higher risk and restrictive ones having minimal, if any, effect on the risk of fracture [116,118].…”

Vitamin D and intestinal calcium transport after bariatric surgery

“…On a microstructural level, cortical thickness decreases and cortical porosity increases at the appendicular skeleton after RYGB, and estimated bone strength declines [16]. Concerns about bone fragility have been corroborated by recent reports that fracture risk is higher after bariatric surgery, with the increased risk driven predominantly by RYGB [17–19]. …”

Bariatric surgery and fractures

“…i3794) aims to fill this gap in knowledge and evidence. 11 The authors did a retrospective, nested case-control study including patients after bariatric surgery (n=12 767), as well as obese (n=32 028) and non-obese (n=126 760) controls matched for sex and age. They used data from physician billing claim databases from 2006 to 2014 to compare the risk and site of fractures in bariatric patients and controls, making comparisons both before and after surgery.…”