Determinants and consequences of insulin initiation for type 2 diabetes in France: analysis of the National Health and Wellness Survey

Gérard Reach,¹ Véronique Le Pautremat,² Shaloo Gupta<sup>3

1</sup>Department of Endocrinology, Diabetes, and Metabolic Diseases, Avicenne Hospital APHP, and EA 3412, CRNH-IdF, Paris 13 University, Sorbonnne Paris Cité, Bobigny, France; ²Kantar Health, Paris, France; ³Kantar Health, Princeton, NJ, USA

Background: The aim of the study was to identify the intrinsic patient characteristics and extrinsic environmental factors predicting prescription and use and, more specifically, early initiation (up to 5 years of disease duration) of insulin for type 2 diabetes in France. A secondary objective was to evaluate the impact of insulin therapy on mental and physical quality of life and patient adherence.
Methods: The data used in this study were derived from the 2008, 2010, and 2011 France National Health and Wellness Survey. This survey is an annual, cross-sectional, self-administered, Internet-based questionnaire among a nationwide representative sample of adults (aged 18 years or older). Of the total of 45,958 persons recruited in France, 1,933 respondents (deduped) were identified as diagnosed with type 2 diabetes. All unique respondents from the three waves, currently using insulin or oral bitherapy or tritherapy at the time of assessment, were included in this analysis.
Results: Early (versus late) initiation of insulin therapy was 9.9 times more likely to be prescribed by an endocrinologist or diabetologist than by a primary care physician (P < 0.0001). Younger age at diagnosis and current smoking habits were significant predictors of early (versus late) insulin initiation (odds ratio [OR] 1.031, 95% confidence interval [CI] 1.005–1.059, P = 0.0196, and OR 2.537, 95% CI 1.165–5.524, P = 0.0191, respectively). Patients with a yearly income ≥€50,000 were less likely to be put on insulin early (P = 0.0399). A link between insulin prescription and complications was shown only in univariate analysis. Mental quality of life was lower in patients on early (versus late) insulin, but only in patients with diabetes-related complications. Insulin users (versus oral bitherapy or tritherapy users) had 3.0 times greater odds of being adherent than uncontrolled oral bitherapy or tritherapy users (OR 2.983, 95% CI 1.37–6.495, P = 0.0059).
Conclusion: This study confirms the role of specialists in early initiation of insulin, and the data presented herein reflect the fact that early initiation is more frequent in younger patients, patients with diabetes-related complications, and current smokers, and less frequent in patients with a higher income. Moreover, we observed that being treated with insulin was not associated with deterioration in quality of life, and insulin-treated patients were more often adherent than uncontrolled oral bitherapy or tritherapy users. These data suggest that doctors' concerns about patient adherence and detrimental effects on quality of life should not be a barrier to their decision regarding early initiation of insulin therapy. Due to the nature of this cross-sectional survey (eg, inability to assess treatment flow), further research is needed to confirm its findings.

Keywords: type 2 diabetes, early insulin initiation, quality of life, adherence, psychological insulin resistance, clinical inertia