Elsevier

Diabetes & Metabolism

Volume 39, Issue 4, September 2013, Pages 306-313
Diabetes & Metabolism

Original article
Changes 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

https://doi.org/10.1016/j.diabet.2013.05.004Get rights and content

Abstract

Aims

Elevated body mass index (BMI) is associated with an increased risk of type 2 diabetes and cardiovascular disease (CVD). This study explored the association between BMI changes in the first 18 months of newly diagnosed type 2 diabetes and the risk of long-term CVD mortality.

Methods

A total of 8486 patients with newly diagnosed type 2 diabetes and no previous history of CVD or cancer were identified from 84 primary-care centres in Sweden. During the first year after diagnosis, patients were grouped according to BMI change: ‘Increase’, or ≥ +1 BMI unit; ‘unchanged’, or between +1 and–1 BMI unit; and ‘decrease’, or ≤ –1 BMI unit. Associations between BMI change and CVD mortality, defined as death from stroke, myocardial infarction or sudden death, were estimated using adjusted Cox proportional hazards models (NCT 01121315).

Results

Baseline mean age was 60.0 years and mean BMI was 30.2 kg/m2. Patients were followed for up to 9 years (median: 4.6 years). During the first 18 months, 53.4% had no change in their BMI, while 32.2% decreased and 14.4% increased. Compared with patients with unchanged BMI, those with an increased BMI had higher risks of CVD mortality (hazard ratio: 1.63, 95% CI: 1.11–2.39) and all-cause mortality (1.33, 1.01–1.76). BMI decreases had no association with these risks compared with unchanged BMI: 1.06 (0.76–1.48) and 1.06 (0.85–1.33), respectively.

Conclusion

Increased BMI within the first 18 months of type 2 diabetes diagnosis was associated with an increased long-term risk of CVD mortality. However, BMI decrease did not lower the long-term risk of mortality.

Résumé

Objectif

Un indice élevé de masse corporelle (IMC) est associé à un risque accru de diabète de type 2 et de maladies cardiovasculaires (CV). Nous avons étudié l’association entre l’évolution de l’IMC au cours des 18 mois après le diagnostic du diabète de type 2 et le risque de mortalité CV à long terme.

Méthodes

Un total de 8486 patients diabétiques de type 2 nouvellement diagnostiqués et sans antécédent de cancer ou de maladies CV issus de 84 centres de soins primaires en Suède ont été étudiés. Au cours de la première année après le diagnostic, les patients ont été regroupés en fonction de l’évolution de l’IMC (augmentation ≥ 1 unité d’IMC; « inchangé » = entre +1 et –1 unité d’IMC ; « diminution » ≤ –1 diminution unité d’IMC). Les associations entre l’IMC et la mortalité CV, définie comme le décès par accident vasculaire cérébral, infarctus du myocarde ou mort subite, ajustées ont été estimées par des modèles de Cox à risques proportionnels.

Résultats

L’âge moyen à l’inclusion était de 60,0 ans et l’IMC moyen de 30,2 kg/m2. Les patients ont été suivis pendant neuf ans (médiane de 4,6 ans). Pendant les 18 premiers mois, 53,4 % n’ont pas changé leur IMC, 32,2 % ont eu une diminution, et 14,4 % une augmentation. Par rapport aux patients avec un IMC inchangé, le groupe présentant une augmentation de l’IMC avait un risque plus élevé de mortalité CV (HR: 1,63 [IC 95 %: 1,11–2,39]) et de mortalité toutes causes (HR: 1,33 [1,01–1,76]). La diminution de l’IMC ne modifiait pas le risque de mortalité (HR: 1,06 [de 0,76– 1,48] et 1,06 [0,85–1,33]) respectivement.

Conclusion

L’augmentation de l’IMC au cours des 18 premiers mois après le diagnostic de diabète de type 2 est associée à une augmentation à long terme du risque de mortalité cardiovasculaire. La diminution de l’IMC ne modifie pas le risque de mortalité.

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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