Introduction: Although insulin is one of the most effective interventions for the treatment of type 2 diabetes, its disadvantages incur substantial medical cost. This study was designed to evaluate the medical costs of Swedish type 2 diabetic patients initiating insulin on top of metformin and/or sulfonylurea (SU), and to evaluate if costs before and after insulin initiation differ for patients where insulin is initiated above or below the recommended glycosylated hemoglobin (HbA1c) level (7.5%).
Methods: This was a register-based retrospective cohort study in which patients were identified from the Sörmland county council diabetes register. Patients being prescribed at least one prescription of metformin and/or SU from 2003 to 2010, and later prescribed insulin, were included.
Results: One hundred patients fulfilled the inclusion criteria and had at least 1 year of follow-up. The mean age was 61 years and 59% of patients were male. Mean time since diagnosis was 4.1 years, and since initiation of insulin was 2.2 years. The mean HbA1c level at index date was 8.0%. Total mean costs for the whole cohort were SEK 17,230 [standard deviation (SD) 17,228] the year before insulin initiation, and SEK 31,656 (SD 24,331) the year after insulin initiation (p < 0.0001). When stratifying by HbA1c level, patients with HbA1c <7.5% had total healthcare costs of SEK 17,678 (SD 12,946) the year before the index date and SEK 35,747 (SD 30,411) the year after (p < 0.0001). Patients with HbA1c levels ≥7.5% had total healthcare costs of SEK 16,918 (SD 19,769) the year before the index date and SEK 28,813 (SD 18,779) the year after (p < 0.0001).
Conclusion: Despite the small sample size, this study demonstrates that mean annual medical costs almost double the year after patients are initiated on insulin. The costs increased the year after insulin initiation, regardless of the HbA1c level at initiation of insulin, and the largest increase in costs were due to increased filled prescriptions.