Introduction: To investigate the clinical effects associated with premixed insulin (PM) and basal insulin [insulin NPH (NPH), insulin glargine (IG), insulin detemir (ID)], in insulin-naïve patients with type 2 diabetes in routine clinical care.
Materials and methods: Cohort study based on data from the Swedish National Diabetes Register, including 5,077 patients, resident in the Western region of Sweden. Patients were included between 1 July 2006 and 31 December 2009 and followed for 12 months. Changes in HbA1c, body mass index (BMI) and required insulin doses were compared between the different insulin types. Covariance adjustments were performed to adjust for differences between the groups.
Results: NPH, IG, ID and PM were all associated with significant reductions in HbA1c, mean ± standard deviation ranged between 6.6 ± 17.4 mmol/mol (IG) and 8.9 ± 17.7 mmol/mol (NPH), during the 12 months of follow-up. There were no statistically significant differences in the magnitude of HbA1c reduction between the insulin types. PM required 59% higher and ID 25% higher insulin doses to achieve a similar HbA1c reduction as NPH. PM was associated with a significantly greater increase in BMI compared with NPH (p = 0.016), while IG and ID did not differ significantly from NPH. The number of patients experiencing severe hypoglycemia was low, but highest in patients treated with PM (p = 0.023).
Conclusions: NPH, IG, ID and PM were found to be equally effective in lowering HbA1c in insulin-naïve patients with type 2 diabetes in routine clinical care in Sweden. The effects on weight, dose and treatment persistence support the recommendation of NPH or IG as first and second choices in this group of patients requiring initiation of insulin treatment.