The rate of treatment failure with metformin
monotherapy was higher in this cohort than in
similar cohorts of adults treated with metformin,13-15
although the definition of failure differed
among the studies. The reason for the
decreased durability of glycemic control with
metformin is unclear but is unlikely to be due to
poor medication adherence, since adherence was
more than 80% during the first year of the study,
when half the patients had treatment failure, and
there was no significant difference in the rate of
loss of glycemic control between participants who
adhered to the medication regimen and those
who did not. Further analysis is required to determine
whether the apparent decrease in the
durability of glycemic control with metformin in
adolescents as compared with adults reflects biologic
differences, pathophysiological differences,
or both.