Metformin still formidable first line treatment for type 2 diabetes

Generic metformin 500-mg tablets, 

as sold in the United Kingdom
– Wikipedia

DIABETES DIGEST – Oct. 31, 2014 – A new study in JAMA Internal Medicine found once again that metformin should be the first line treatment for type 2 diabetes, which isn’t really the news. The study also found that despite the guidelines recommending metformin first, only 57.8 percent of newly diagnosed patients began treatment with metformin.

Since metformin became the standard of care for type 2 diabetes, six classes of drugs have been introduced including thiazolidinediones (Actos®) that remove sugar from the blood, sulfonylureas (Amaryl, Glucotrol) that increase the amount of insulin produced by the pancreas, GLP-agonists (Byetta and Victoza) that promote weight loss, DPP-IV blockers (Onglyza, Tradjenta, Galvus) that decrease blood sugar levels, Meglitinides (Prandin and Starlix) which also lower blood sugar levels, and alpha-glucosidase blockers (Precose and Glyset) that block absorption of carbohydrates.

The study, led by Dr. Seth Berkowitz of the Department of Medicine at Brigham and Women’s Hospital, Harvard Medical School, analyzed the insurance records of 15,516 patients who were prescribed oral blood sugar-lowering medications between 2009 and 2013. They looked at the first medications prescribed and the second medication prescribed within 90 days of the end of the first prescription.

They found that 8,964 patients (57.8 percent) were initially prescribed metformin and only 25 percent of those added a second drug within 90 days. They also found that among those who started with sulfonylureas, 32 percent added a second medication, while 39 percent of those who started thiazolidinediones, and 38 percent of those who started with DPP-IV drugs added second medications soon after.

In addition they found that there was no reduction in risk of low blood sugar events, emergency department visits, or cardiovascular events among those who started on medications other than metformin.

In an accompanying editorial in the same journal, Drs. Jodi Segal and Nisa Maruthur noted that the study did not include a newer class of drugs called sodium-dependent glucose transporter 2 inhibitors, or SGLT blockers as they had not been approved at the time of the study. 

“Less understandable is the exclusion of injectable medications from the glucagon-like peptide-1 agonists (GLP-1) class despite their approval for use as first line therapy and availability since 2005,” they wrote.

More importantly, they raised the question of whether having to add a second drug is measure of effectiveness since drug response can vary greatly between individuals and that intensifying treatment is appropriate in terms of reaching patients’ individual blood sugar targets.