PURPOSE We wanted to determine whether metformin is an effective medication for treatment of overweight or obese adults who do not have diabetes mellitus or polycystic ovary syndrome (PCOS).
METHODSWe searched MEDLINE (1966MEDLINE ( -2003, EMBASE (1986EMBASE ( -2003, Allied and Complementary Medicine Database (1985-2003), International Pharmaceutical Abstracts (1970Abstracts ( -2003, the Cochrane Library, American College of Physicians Journal Club, Database of Abstracts of Reviews of Effects, Cochrane Controlled Trials Register, MEDLINE In-Process & Other Non-Indexed Citations, reference lists of retrieved articles, and articles by selected authors and pharmaceutical manufacturers. Inclusion criteria were being obese or overweight determined by a BMI of 25 kg/m 2 or greater or waist-to-hip ratio (WHR) of more than 0.8, metformin use, and aged 18 years or older. Exclusion criteria were a diagnosis of diabetes mellitus, polycystic ovarian syndrome or descriptors of polycystic ovarian syndrome, human immunodefi ciency virus infection, and concomitant antipsychotic medications. Trials were graded on an 11-point Jadad scale. Only randomized controlled and blinded trials were accepted. Two reviewers independently extracted data from each trial. Primary outcomes measured were changes in BMI, WHR, and weight.RESULTS Fifty-seven potentially relevant studies were initially identifi ed; 48 were excluded because of lack of randomization, lack of blinding, failure to meet inclusion or exclusion criteria, inaccessible outcomes, or improper study design. Nine clinical trials met criteria for validity assessment. Four studies used the parameter of waist-to-hip ratio, 3 studies included BMI, and 8 used weight. Two of the 9 studies showed a small reduction in WHR.
CONCLUSION
INTRODUCTIONO besity has become a major public health concern in the United States. More than 60% of adults are overweight or obese, 1 with a body mass index (BMI) greater than 25 kg/m.2 Obesity affects persons regardless of age, race, ethnicity, and sex.2 It is associated annually with 400,000 deaths, and associated health care costs exceed $177 billion.
2A combination of genetic, metabolic, behavioral, environmental, cultural, and socioeconomic factors contribute to a person' s body weight.2 An elevated BMI increases the prevalence, morbidity, and mortality of type 2 diabetes mellitus, hypertension, heart disease, stroke, osteoarthritis, respiratory tract disorders, gallstones, certain types of cancer, and psychological disorders. Metformin, the biguanide most widely used for the treatment of type 2 diabetes mellitus, 8 may be useful in aiding weight loss. In diabetic patients, it suppresses endogenous glucose production and may also act as an insulin sensitizer. It also helps diabetic patients lose weight or at least keep their weight stable. 9 In addition to its use in treatment of diabetes, metformin has also become commonly prescribed for patients with polycystic ovary syndrome (PCOS), and its use has resulted in weight reduction in those pat...
