DPP4 and polycystic ovary syndrome: COM = metformin combined with exenatide; DCI-IPG = d-chiro-inositol-inositol phosphoglycan; DPP4 = dipeptidyl peptase-4; GH = growth hormone; HRQOL = health-related quality of life; NLRP-3 = nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3; OGTT = oral glucose tolerance test; PCOS = polycystic ovarian syndrome; PM = pioglitazone-metformin complex; QOL = quality of life; VAT = visceral adiposity