The impact of insulin glargine on clinical and humanistic outcomes in patients uncontrolled on other insulin and oral agents: an office-based naturalistic study

Objective: Controlling blood glucose levels in patients with diabetes often requires aggressive treatment, which may in turn cause hypoglycemia and/or decreased health-related quality of life (HRQOL). Insulin glargine, a long-acting insulin, has shown benefits of decreased nocturnal hypoglycemia without significant weight gain, while providing good glycemic control in clinical trials. These benefits have often been reported in studies of less than 1 year duration. The objective of this study was to evaluate the effectiveness of insulin glargine over a 12-month period in a clinical practice setting, and measure its effects on HRQOL in a subset of patients. Design and Methods: Patients with diabetes in a large private endocrinology practice were initiated on insulin glargine. Patients were divided into 2 cohorts: the first group included patients with type 1 diabetes (T1D, n = 135); the second group included patients with type 2 diabetes previously on insulin and/or oral agents (T2D, n = 180). The HRQOL subset analysis included 50 patients from the above study. Patients completed a 40-item questionnaire adapted from the Diabetes Symptom Checklist-Revised (DSC-R) and the Medical Outcomes Study 36-item Short-Form Health Survey (SF-36) at weeks 0, 2, 6, 12, and 16. Results: Patients in both cohorts experienced statistically significant decreases in mean (+/- SD) A1C: group T1D, -0.28 +/- 1.47 (P = 0.0307); group T2D, -0.60 +/- 1.51 (P < 0.0001), with no significant changes in body mass index. In the year following insulin glargine therapy, there were significantly fewer hypoglycemic events per patient than in the year prior to insulin glargine therapy (group T1D: -0.33, P = 0.002; group T20: -0.20, P = 0.004). HRQOL subset analysis also revealed a significant decrease in A1C (P < 0.0001) after 16 weeks of therapy with insulin glargine. In this subset of patients, there was a significant improvement in overall well being (P = 0.0019), emotional well being (P = 0.003), total symptom scores (P < 0.0001), and total symptom distress (P < 0.0001). The limitations of the study are those inherently associated with naturalistic observational studies such as recall bias and compliance. Conclusions: Insulin glargine use over a 12-month period in a clinical practice setting was shown to significantly improve A1C without adversely impacting weight or the occurrence of hypoglycemia. Significant improvements were also observed in HRQOL.