BACKGROUND: While bariatric surgery is effective for severe obesity, some research suggests that it might double fracture risk. However, most of the previous studies compare patients undergoing surgery to those not offered such treatments, making the results difficult to interpret. In addition, we do not know which patients who receive bariatric surgery are at highest risk of breaking their bone/s. The lack of convincing evidence means screening for bone health is not routinely carried out in the NHS in patients undergoing bariatric surgery.
PURPOSE: We aim to study if there is an increased risk of bone fracture/s following bariatric surgery. In addition, we will look for key factors to identify those most likely to suffer such fractures.
DESIGN/METHODS: We will use anonymised GP and hospital records to study these associations. According to figures provided by CPRD, >10,900 patients undergoing bariatric surgery for obesity are available. To avoid the biases mentioned above we will use advanced methods applied in vaccine safety studies (called 'self-controlled case series'), where the risk of fracture in the periods before and after surgery are compared for each patient.
POTENTIAL IMPORTANCE: Our findings will help target patients in need for bone health assessment and/or treatment/s at the time before undergoing bariatric surgery.
OBJECTIVES
1. To use self-controlled case series (SCCS) to assess fracture risk before and after bariatric surgery.
2. To determine key predictors of post-operative fracture, and produce a fracture risk prediction tool.
METHODS
- Data sources: CPRD linked to HES.
- Participants: patients in CPRD with a body mass index (BMI) of 35+ undergoing bariatric surgery. Patients with <1 year of data or with a gastrointestinal cancer before surgery will be excluded.
- Exposures:
Bariatric surgery will be identified using READ (CPRD) and OPCS4 (HES) codes.
Predictors of post-operative fracture/s, based on consensus and literature review: age, gender, systemic steroid use, BMI, fracture history, smoking, alcohol drinking, inflammatory arthritis, secondary osteoporosis, type 2 diabetes and related treatments, other drugs affecting fracture risk, socio-economic deprivation, and available blood tests.
- Outcomes:
Primary outcome will be any osteoporotic fracture/s (excluding skull, face, or digits) in the 5 years
following bariatric surgery
Secondary: 1.major fracture (hip, wrist/forearm, spine, and proximal humerus), 2.peripheral fracture/s (wrist-forearm, ankle, and proximal humerus).
DATA ANALYSIS: Incidence rate ratios (IRR) will be calculated for fracture/s within the "exposure" (5 years
post-surgery) period compared to baseline (presurgery) using SCCS methods. A cohort design will be used to identify key predictors of 5-year postoperative fracture
Primary: Any osteoporotic fracture/s (any site except skull, face, or digits)
- Secondary1: major fracture (hip, wrist/forearm, spine, and proximal humerus)
- Secondary2: peripheral fracture/s (wrist/forearm, ankle, proximal humerus)
Daniel Prieto-Alhambra - Chief Investigator - University of Oxford
Daniel Prieto-Alhambra - Corresponding Applicant - University of Oxford
Andrew Judge - Collaborator - University of Oxford
Antonella Delmestri - Collaborator - University of Oxford
Cyrus Cooper - Collaborator - University of Southampton
Danielle Robinson - Collaborator - University of Manchester
Garry TAN - Collaborator - Oxford University Hospitals
Ian Douglas - Collaborator - London School of Hygiene & Tropical Medicine ( LSHTM )
Kassim Javaid - Collaborator - University of Oxford
Sara Khalid - Collaborator - University of Oxford
Victoria Y Strauss - Collaborator - University of Oxford
HES Admitted Patient Care;ONS Death Registration Data;Patient Level Index of Multiple Deprivation