We thank DeVries et al. (1) for their letter in this issue of Diabetes Care. We acknowledge that nonrandomized parallel design studies have an inherent selection bias that could exaggerate group differences. Regarding the design of our study, we wanted to be as inclusive as possible in our review; therefore, we analyzed all the studies that met the criteria listed in the introduction of the article. We also clearly informed the readers that some of the parallel design studies (2–12) did not follow a randomized design, which is a methodological issue that we incorporated in subsequent discussions pertaining to the results.

The test for homogeneity for all 11 studies was not statistically significant (P = 0.99), implying that there was no evidence to indicate the studies were different. We reran the analyses for the parallel design studies, separating the randomized and nonrandomized studies. For the randomized studies, a Q-statistic of 3.92 (P = 0.73) suggests the studies are homogeneous. The weighted summary mean difference was 0.375, with a 95% CI of 0.14–0.61, indicating that there was a significant difference between the two treatment approaches. For the nonrandomized studies, a Q-statistic of 24.99 (P > 0.99) suggests the studies are homogeneous. The weighted summary mean difference was 1.32, with a 95% CI of 1.13–1.51, indicating that there was a significant difference between the two treatment approaches. In sum, both sets of studies show a significant difference between continuous subcutaneous insulin infusion therapy and multiple daily injection or conventional therapy, although as expected, the average difference in means is larger for the nonrandomized studies.

In addition, the meta-analyses were separetely conducted on parallel (n = 11) and paired designs (n = 41) separately. We arrived at the same conclusions for both sets of analyses. Our discussion and recommendations are based on both analyses and take into account all methodological and quantitative observations made with respect to the studies involved in the meta-analysis.

J.W.B. has received a grant/support from MiniMed.

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