We agree with Blumer’s (1) contention that patients with type 1 diabetes using continuous subcutaneous insulin infusion (CSII) therapy represent a well-motivated patient population. In this context, he asks whether differences in patient motivation (as reflected in adherence to frequent self-monitoring of blood glucose and regular contact with diabetes educators) may underlie the finding of improved glycemic control with CSII as compared with multiple daily insulin injection (MDII) therapy in our recent pooled analysis of randomized controlled trials comparing CSII and MDII therapy using rapid-acting analogs in adults with type 1 diabetes (2).
Given the clinical trial setting and the crossover nature of the data reported, we feel that differences in patient motivation are likely not the basis for the observed results. Specifically, the data included in the analysis are from randomized clinical trials, in which treatment allocation (i.e., CSII vs. MDII) was randomized and clinical management (i.e., frequency of clinic visits) was standardized. Accordingly, one would not expect systematic bias regarding patient motivation and adherence to be a significant factor. Furthermore, it is particularly important to note that the pooled analysis (Fig. 2 in ref. 2) shows the impact of baseline glycemic control on mean improvement in A1c by treatment modality in those patients for whom crossover data were available. As such, the relationship between greater improvement in A1c with CSII versus MDII in those patients with poorer baseline glycemic control was demonstrated in a patient population in which intrapatient treatment effect could be studied (since the crossover patients, by definition, had standardized treatment periods using each of CSII and MDII during the clinical trials in question). Thus, because this comparison between CSII and MDII was performed in the very same patients, we feel that differences in patient motivation likely did not affect the observed findings.
While patient motivation may not underlie our findings, we nevertheless strongly agree with the contention that patient-driven factors, such as willingness to assume substantial responsibility for their own care, can greatly impact the effectiveness of intensive insulin therapy in clinical practice. As recommended in the American Diabetes Association position statement on insulin pump therapy (3), patient motivation must remain an important factor to consider when evaluating the suitability of CSII for an individual patient.
