Risk of fracture after bariatric surgery in the United Kingdom: population based, retrospective cohort study
BMJ 2012; 345 doi: https://doi.org/10.1136/bmj.e5085 (Published 06 August 2012) Cite this as: BMJ 2012;345:e5085
- Arief Lalmohamed, pharmacoepidemiologist1,
- Frank de Vries, assistant professor 123,
- Marloes T Bazelier, pharmacoepidemiologist1,
- Alun Cooper, general practitioner 4,
- Tjeerd-Pieter van Staa, head of research and honorary professor of epidemiology 125,
- Cyrus Cooper, director and professor of rheumatology26,
- Nicholas C Harvey, senior lecturer and honorary consultant rheumatologist 2
- 1Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, Netherlands
- 2MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton General Hospital, Southampton, UK
- 3Maastricht University Medical Centre, Department of Clinical Pharmacy and Toxicology, Maastricht, Netherlands
- 4Bridge Medical Centre, Crawley, UK
- 5General Practice Research Database, Medicines and Healthcare Products Regulatory Agency, London, UK
- 6Institute of Musculoskeletal Sciences, University of Oxford, Oxford, UK
- Correspondence to: C Cooper, MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton General Hospital, Southampton SO16 6YD, UK cc{at}mrc.soton.ac.uk
- Accepted 6 July 2012
Abstract
Objectives To estimate fracture risk in patients receiving bariatric surgery versus matched controls.
Design Population based, retrospective cohort study.
Setting Use of records from the United Kingdom General Practice Research Database, now known as the Clinical Practice Research Datalink (from January 1987 to December 2010).
Participants Patients with a body mass index of at least 30, with a record of bariatric surgery (n=2079), and matched controls without a record (n=10 442). Each bariatric surgery patient was matched to up to six controls by age, sex, practice, year, and body mass index. Patients were followed from the date of bariatric surgery for the occurrence of any fracture. We used time dependent Cox regression to calculate relative rates of fracture, adjusted for disease and previous drug treatment, and time-interaction terms to evaluate fracture timing patterns.
Main outcome measure Relative rates of any, osteoporotic, and non-osteoporotic fractures.
Results Mean follow-up time was 2.2 years. Overall, there was no significantly increased risk of fracture in patients who underwent bariatric surgery, compared with controls (8.8 v 8.2 per 1000 person years; adjusted relative risk 0.89, 95% confidence interval 0.60 to 1.33). Bariatric surgery also did not affect risk of osteoporotic and non-osteoporotic fractures. However, we saw a trend towards an increased fracture risk after three to five years following surgery, as well as in patients who had a greater decrease in body mass index after surgery, but this was not significant.
Conclusion Bariatric surgery does not have a significant effect on the risk of fracture. For the first few years after surgery, these results are reassuring for patients undergoing such operations, but do not exclude a more protracted adverse influence on skeletal health in the longer term.
Footnotes
Contributors: All authors drafted the article, revised it critically for important intellectual content, and approved the final version to be published. CC had full access to all the data in the study and is the study guarantor. All authors were responsible for the study concept and design, and participated in the analysis and interpretation of data. AL led the statistical analysis. CC and NCH were responsible for the data acquisition.
Funding: This study was funded by a research grant from the International Osteoporosis Foundation and SERVIER. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: All authors have completed the Unified Competing Interest form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare: support from the International Osteoporosis Foundation and SERVIER for the submitted work; AL, FV, MB, and TS are employed by the Division of Pharmacoepidemiology and Clinical Pharmacology at Utrecht Institute for Pharmaceutical Sciences, which has received unrestricted research funding from the Netherlands Organisation for Health Research and Development, Dutch Health Care Insurance Board, Royal Dutch Pharmacists Association, private-publicly funded Top Institute Pharma (www.tipharma.nl, which includes cofunding from universities, government, and industry), EU Innovative Medicines Initiative, EU 7th Framework Program, Dutch Medicines Evaluation Board, Dutch Ministry of Health and industry (including GlaxoSmithKline, Pfizer); no financial relationships with any organisations that might have an interest in the submitted work in the previous 3 years; no other relationships or activities that could appear to have influenced the submitted work.
Ethical approval: The Clinical Practice Research Datalink group obtained ethical approval from a multicentre research ethics committee for a purely observational research using data from the database, such as ours. This study obtained approval for the independent scientific advisory committee of the Clinical Practice Research Datalink, which is responsible for reviewing protocols for scientific quality.
Data sharing: No additional data available
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