Original articleChanges in body mass index following newly diagnosed type 2 diabetes and risk of cardiovascular mortality: A cohort study of 8486 primary-care patientsImpact des modifications de l’IMC après le diagnostic de diabète de type 2 sur le risque à long terme de mortalité cardiovasculaire chez 8486 patients en soins primaires
Introduction
Weight control or the attainment of optimal body weight is a recommended treatment goal in type 2 diabetes patients based on the subsequent beneficial effects on cardiovascular disease (CVD) risk factors [1], [2], [3]. The suggested CVD risk reduction with weight loss has been supported by one small observational study of diabetes patients and by extrapolated data from non-diabetic populations [4]. Bariatric surgery for severe obesity with sustained and substantial weight losses of 14–25% over several years has also shown significantly reduced risk of mortality compared with untreated patients [5]. However, the Look AHEAD (Action For Health in Diabetes) trial was prematurely terminated in 2012 because it failed to demonstrate any associations between CVD risk and sustained moderate weight loss in diabetic patients using prospective lifestyle interventions [6]. The clinical effect of weight loss on CVD in the context of routine lifestyle changes in general diabetes care has previously been debated and remains unsettled in the light of recent results [6], [7]. Weight gain has been reported to be associated with increased CVD risk in diabetic patients; however, clinical interpretation is difficult due to the secondary nature of the results and the methods used for weight-change calculations [8], [9]. Indeed, the importance of weight changes in type 2 diabetes patients on fixed outcomes is currently unclear, thereby supporting the need for new studies addressing this issue.
The objective of the present study was to investigate the association between weight change and risk of CVD mortality in a large primary-care-based sample of patients with newly diagnosed diabetes in a real-world setting.
Section snippets
Methods
The study was based on the Retrospective Epidemiological Study to Investigate Outcome and Mortality with Glucose-lowering Drug Treatment in Primary Care (ROSE) study [10]. In 2010, patients’ data were extracted from 84 primary-care centres in Sweden, using the Pygargus Customized Extraction Program (CXP) [11], to constitute a representative sample of both publicly and privately owned primary-care centres (61% and 39%, respectively) [12], [13]. The 84 centres selected made up approximately 8% of
Results
Baseline mean age was 60.0 years (range 35–79 years) and mean BMI was 30.2 kg/m2 (range 16.7–58.5 kg/m2). Mean overall time between baseline and second BMI registration dates was 383 days (range 46–545, SD 121 days). Patients were followed for up to 9 years, with a median follow-up time of 4.6 years and 38,300 patient-years. Slightly more than half the patients had an unchanged BMI (53.4%), and more patients had a decrease (32.2%) than increase (14.4%) in BMI (Table 1). During follow-up, the
Discussion
The present study demonstrates that slightly more than half of patients (53.4%) maintain their BMI with no changes during the first 18 months after type 2 diabetes diagnosis. The least common observation was an increased BMI (14.4%) by more than 1 BMI unit (∼3.6 kg), and this group had a 63% greater risk of CVD mortality compared with patients with unchanged BMI. Interestingly, no risk reduction was detected in the 32.2% of patients whose BMI decreased by more than 1 BMI unit compared with those
Conclusion
Weight gain in patients with newly diagnosed type 2 diabetes may be more hazardous than previously recognized, and efforts should be made to prevent weight increases in diabetes patients. However, weight loss did not lower the long-term risk of either CVD or all-cause mortality. Nevertheless, the results of this retrospective study need to be confirmed in prospective studies before any definitive conclusions can be drawn.
Disclosure of interest
J.B. holds a full-time position at AstraZeneca as an epidemiologist. J.S., P.N., C.J.Ö, B.S. and G.J. have received compensation for the work on this report from AstraZeneca.
Contributions: J.B. researched data, contributed to the discussion, and wrote, reviewed and edited the manuscript. B.S. had full access to the data and performed statistical analyses. J.S., C.J.Ö, P.N., B.S. and G.J. researched data, contributed to the discussion, reviewed and edited the manuscript. J.B. is the guarantor of
Acknowledgements
Special thanks go to Professor Jan Cederholm, Department of Public Health and Caring Sciences/Family Medicine and Clinical Epidemiology, Uppsala, Sweden, for advice and input to this work.
Lena Ferntoft working for AstraZeneca made significant contributions to this study. The authors acknowledge the database management by Ulf Hellström and data extraction by Pygargus AB.
Funding: This study was funded by AstraZeneca.
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