Subgroup analyses suggest that metformin plus
rosiglitazone was more effective in girls than in
boys and that metformin alone was less effective
in non-Hispanic black participants than in other
racial or ethnic groups. The reasons for these differences
in response to treatments according to
sex and race or ethnic group are not clear, although
differences in insulin sensitivity and insulin
secretion,16-18 adiponectin,19 fitness,20 and
routine activity levels have been reported. Further
analysis of these variables, as well as other covariates,
such as socioeconomic status and psychosocial
functioning, is needed to more fully understand
these findings.