The Magnitude of Weight Loss Induced by Metformin is Independently Associated with BMI at Baseline in Newly Diagnosed Type 2 Diabetes: Post-hoc Analysis from Data of a Phase IV Open-labeled Trial

Abstract

Background. The impact of metformin on body weight is variable in T2DM patients among studies. The reasons for the discrepancies are still unknown.

JPEN Journal Club 54. Correlation Coefficients

“…1 In the paper to be discussed in this installment of the Journal of Parenteral and Enteral Nutrition Journal Club, Zhou et al attempt to provide more details about this phenomeonon. 2 The data came from a retrospective analysis of a prospective, uncontrolled, observational study that was reported in 2013. 3 In that original study, newly diagnosed adult diabetics who were treatment naive were enrolled in an uncontrolled 3-arm study; patients were assigned to the groups depending on whether they were classified as normal, overweight, or obese, according to their baseline body mass index (BMI, kg/m 2 ).…”

“…Thus, the remaining results consisted of comparisons between the 4 quartiles of weight loss. Zhou et al began by trying to provide the clinical characteristics of the groups, but only those of 3 of the groups were tabulated 2 ; the details of group 4 (those with the greatest weight loss) were not included in that table. The text of the paper indicated that, compared with the group with the lowest weight loss, those with the greatest weight loss had significant associations with 4 baseline characteristics (heaviest weight, highest BMI, largest waistline, and lowest serum albumin level).…”

“…The data from 15 of these comparisons were presented in Table 2 of the paper by Zhou et al 2 That table provided both the correlation coefficient (known as the r-value) and the probability that the observed association was simply due to chance (the P-value). The correlation coefficients for baseline weight, serum albumin level, BMI, and waistline were .257, −.207, .135, and .156; the respective P-values were .000, .000, .020, and .007.…”

“…It should be noted that the absolute value (disregarding the plus or minus signs) of the r-values in Table 2 of the Zhou et al paper 2 were all <0.3. The 4 "significant" correlations were graphed in Figure 2 of the paper, 2 and it can be appreciated how scattered the individual points really are. In fact, if I were to ask you to draw the best straight line that you could through each of those 4 graphs, you would have a hard time doing so.…”

“…At least in nonrandomized trials, metformin has been associated with weight loss 1 . In the paper to be discussed in this installment of the Journal of Parenteral and Enteral Nutrition Journal Club, Zhou et al attempt to provide more details about this phenomeonon 2 . The data came from a retrospective analysis of a prospective, uncontrolled, observational study that was reported in 2013 3 .…”