A newer drug appeared to delay the progression of the most common form of diabetes a little longer than two older medications but with greater weight gain and more fractures, a large study has found.

The results, along with the higher cost of the new drug, suggest that metformin, sold as Glucophage and other brands, should remain the first choice for most newly diagnosed patients with Type 2 diabetes, several specialists said.

Avandia, by GlaxoSmithKline PLC, did a better job of controlling blood-sugar problems than the two older drugs, according to the study of 4,360 newly diagnosed patients. After five years, only 15 percent of those taking Avandia, or rosiglitazone, had to add a second drug to treat their disease compared with 21 percent of those taking metformin and 34 percent taking glyburide, sold as Micronase, Diabeta and other names, the study found.

However, 62 on Avandia developed a heart problem compared with 58 on metformin and 41 on glyburide – differences the company says could have occurred by chance alone. Avandia users also gained an average of more than 10 pounds over five years; metformin users lost more than six pounds while glyburide users gained three and then stabilized. Fractures, especially in women, were nearly twice as common among those taking Avandia.

“It comes at a price,” Dr. Om Ganda, an endocrinologist at the Joslin Diabetes Center in Boston, said of Avandia’s potential for slowing diabetes progression. Ganda had no role in the study.

Type 2 is the most common form of diabetes, afflicting more than 200 million people worldwide. It occurs when the body cannot make enough insulin or effectively use what it does make. Obesity increases the risk.