PPARD and Insulin resistance: In this study, we observed that the FINS and HOMA-IR levels of the subjects with at least one C allele of the PPARD rs2016520 were significantly lower than those with the TT genotype after 6 months of treatment, which suggested that the PPARD rs2016520 TT genotype conferred the poor exenatide response through a reduction of insulin resistance, as measured by HOMA-IR.