Metformin improves polycystic ovary syndrome symptoms irrespective of pre-treatment insulin resistance.
OBJECTIVE
Insulin resistance (IR) and obesity are common features of the polycystic ovary syndrome (PCOS). Insulin-sensitizing agents have been shown to improve both reproductive and metabolic aspects of PCOS, but it remains unclear whether it is also beneficial in lean patients without pre-treatment IR. The aim of this study was to determine the influence of metformin on the clinical and biochemical parameters of PCOS irrespective of the presence of basal obesity and IR.


METHODS
The effect of 6 months of metformin treatment was prospectively assessed in 188 PCOS patients, divided into three groups according to body mass index (BMI; lean: BMI<25 kg/m2, overweight: BMI 25-29 kg/m2, and obese: BMI30 kg/m2). Outcome parameters, which were also assessed in 102 healthy controls, included body weight, homeostasis model assessment for IR (HOMA-IR), fasting glucose and insulin levels, area under the curve of insulin response (AUCI), hyperandrogenism, and menstrual irregularities.


RESULTS
In comparison with the respective BMI-appropriate control groups, only obese but not lean and overweight PCOS patients showed differences in fasting insulin and HOMA-IR. Metformin therapy significantly improved all outcome parameters except fasting glucose levels. Subgroup analyses revealed that in the group of lean PCOS patients without pre-treatment IR, metformin significantly improved HOMA-IR (1.7+/-1.0 vs 1.1+/-0.7 micromol/lxmmol/l2) and fasting insulin levels (7.7+/-4.2 vs 5.4+/-3.9 mU/l), in addition to testosterone levels (2.6+/-0.9 vs 1.8+/-0.7 nmol/l), anovulation rate (2.3 vs 59.5%), and acne (31.8 vs 11.6%; all P<0.017). In the overweight and obese PCOS groups, metformin also showed the expected beneficial effects.


CONCLUSIONS
Metformin improves parameters of IR, hyperandrogenemia, anovulation, and acne in PCOS irrespective of pre-treatment IR or obesity.
Tan
Susanne
S
Division of Endocrinology, Department of Medicine, University Hospital of Essen Medical School, Hufelandstr. 55, 45122 Essen, Germany. susanne.tan@uk-essen.de
Hahn
Susanne
S
Benson
Sven
S
Dietz
Tiina
T
Lahner
Harald
H
Moeller
Lars C
LC
Schmidt
Markus
M
Elsenbruch
Sigrid
S
Kimmig
Rainer
R
Mann
Klaus
K
Janssen
Onno E
OE
D001835:Body Weight / Q000187:drug effects / Q000502:physiology; D005260:Female; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology*; D008687:Metformin / Q000494:pharmacology / Q000627:therapeutic use*; D009765:Obesity / Q000188:drug therapy / Q000503:physiopathology; D050177:Overweight / Q000188:drug therapy / Q000503:physiopathology; D011085:Polycystic Ovary Syndrome / Q000188:drug therapy* / Q000503:physiopathology; D013851:Thinness / Q000188:drug therapy / Q000503:physiopathology; D016896:Treatment Outcome
D008687:Metformin