Mortality in Adult-Onset Autoimmune Diabetes Is Associated With Poor Glycemic Control

Results from the HUNT Study

  1. Sofia Carlsson, PHD2
  1. 1Centre for Health Equity Studies, Stockholm University/Karolinska Institutet, Stockholm, Sweden
  2. 2Unit of Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
  3. 3Department of Cancer Research and Molecular Medicine, Faculty of Medicine, the Norwegian University of Science and Technology, and Department of Endocrinology, St. Olav University Hospital, Trondheim, Norway
  4. 4HUNT Research Centre, Department of Community Medicine and General Practice, Faculty of Medicine, the Norwegian University of Science and Technology, Levanger, Norway
  5. 5Centre for Occupational and Environmental Medicine, Stockholm County Council, Stockholm, Sweden
  1. Corresponding author: Lisa Olsson, lisa.olsson{at}chess.su.se.

Abstract

OBJECTIVE Knowledge on mortality in autoimmune diabetes with adult onset is limited. We compared mortality in adult-onset autoimmune diabetes and type 2 diabetes, taking into account metabolic risk factors, HbA1c, lifestyle, and socioeconomic factors.

RESEARCH DESIGN AND METHODS Participants of the population-based HUNT2 Study (second survey of the Norwegian HelseUndersøkelsen i Nord-Trøndelag Study; n = 64,264) were followed up prospectively for mortality in the Cause of Death Registry (1995–2009). Diabetes with onset ≥35 years was classified as autoimmune diabetes in adults if anti-GAD was positive (n = 208) and as type 2 diabetes if anti-GAD was negative (n = 2,425). Hazard ratios (HR) of mortality from all-causes, cardiovascular disease (CVD), and ischemic heart disease (IHD) were calculated using the Cox proportional hazards model.

RESULTS Prevalence of the metabolic syndrome was lower in autoimmune diabetes than in type 2 diabetes (55 vs. 77%, P < 0.001). Still, autoimmune diabetes was associated with an increased risks of mortality from all-causes (HR 1.55 [95% CI 1.25–1.92]), CVD (1.87 [1.40–2.48]), and IHD (2.39 [1.57–3.64]), equally high as in type 2 diabetes in analyses where individuals without diabetes were used as the reference group. The increased risk was not explained by overweight, lifestyle, socioeconomic position, or presence of the metabolic syndrome. Excess mortality was primarily observed in individuals with elevated HbA1c.

CONCLUSIONS Mortality in autoimmune diabetes was as high as in type 2 diabetes, despite a more favorable baseline metabolic risk profile. Excess risk was associated with poor glycemic control. The results from this study, the largest so far on mortality in autoimmune diabetes in adults, underscore the importance of optimal treatment modalities to improve survival in adult-onset autoimmune diabetes.

  • Received March 7, 2013.
  • Accepted July 20, 2013.

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  1. Diabetes Care
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