An evaluation of patient preference for an alternative insulin delivery system compared to standard vial and syringe.

BACKGROUND

Diabetes mellitus (DM) affects over 18.2 million Americans and diabetes-related medical costs exceed 132 billion dollars per year, totaling more than 12% of the United States healthcare budget. The Diabetes Control and Complications Clinical Trial demonstrated that intensive insulin therapy and the control of plasma glucose can significantly reduce the incidence of late diabetic complications and delay the progression of existing conditions in type 1 diabetes. Optimal glycemic control often requires intensive insulin therapy to maintain a hemoglobin A(1C) (A1C) of less than 7% as recommended by the American Diabetes Association. It is estimated that more than half of the approximately 7 million Americans using insulin do so with suboptimal treatment and while administering one or two insulin injections per day. Non-adherence may be a contributing factor in suboptimal treatment. For a variety of reasons, many patients diagnosed with diabetes and treated with insulin are non-adherent.

SCOPE

The primary objective of this study was to evaluate preference for an insulin delivery system comparing a disposable doser (InnoLet) to the standard vial/syringe. In a prospective, randomized, open-label, two-period, crossover study, 260 patients were enrolled (age > or = 18 years, with type 1 or 2 diabetes, and receiving NPH or regular or 70/30 insulin for at least 6-months). A total of 162 patients completed both treatment arms. Excluded were those unable to read/write English or administer their own injections, pregnant/lactating women, those using antipsychotics, and those with a history of alcohol abuse or cognitive impairment. Patients completed the eight-item Diabetes Fear of Self-Injection Questionnaire at baseline, week 12 and week 24. Items were rated on a 4-point Likert scale (1 = almost never; 4 = almost always) with a maximum fear score of 32. At week 24, patients completed a preference survey.

FINDINGS

Of the 162 patients completing both treatment arms, 89 (55.0%) were in the vial/syringe to disposable doser treatment arm, 50% were female and mean age was 60 +/- 11 years. Patients in both treatment arms displayed little significant differences in baseline characteristics. Patients reported significantly lower fear of self-injection after using the disposable doser compared to vial/syringe (mean +/- SEM: 9.5 +/- 0.2 vs. 11.2 +/- 0.4; p < 0.0001). Most patients (71.5%) indicated a preference for the disposable doser compared to the vial/syringe method (p < 0.0001).

CONCLUSION

The majority of patients preferred the disposable doser, and reported significantly less fear of self-injection using this delivery system. There are some potential limitations to consider. A randomization bias may have been present, patients who enrolled in this study were those who were actively seeking medical treatment for diabetes, insulin pens and cartridges are not available for all types of insulin regimens, pre-filled pens and cartridges may not be altered and, in general, alternative insulin delivery systems tend to be more costly than insulin sold in traditional vials. However, insulin may have greater patient acceptance and less psychological distress when administered via an alternative delivery system.