A new US review of published scientific literature suggests that older oral drugs for treating adults with type 2 diabetes mellitus are just as effective, if not more so, than newer, more expensive ones.
The study is published in the early online edition of the journal Annals of Internal Medicine.
The study suggests that older drugs such as the second generation sulfonylureas and metformin, have the same or superior effect on controlling blood sugar, lipids and other markers of diabetes compared to the newer, more expensive thiazolidinediones (eg Avandia, Actos), alpha-glucosidase inhibitors (Precose, Glyset) and meglitinides (Prandin, Starlix).
Many new drugs to treat diabetes have emerged on the market in the last few years, making it very confusing for the 21 million Americans who have the condition.
This is the first time published evidence on diabetes drugs has been used to systematically compare all the drugs with one another. The review summarizes the evidence available for each drug’s impact on a number of intermediate endpoints (as opposed to major endpoints like death due to heart disease). The main intermediate endpoints taken into account in the review were: hemoglobin A1c (a surrogate marker for blood glucose), lipids (fatty acids), adverse effects, risk factors for diseases of the heart and major blood vessels (macrovascular risk), and body weight.
The study was the work of Dr. Shari Bolen, of Johns Hopkins University in Baltimore, Maryland, and colleagues. They said that “large, long-term comparative studies are needed to determine the comparative effects of oral diabetes agents on hard clinical end points.”
Bolen and colleagues sourced articles from MEDLINE, EMBASE and Cochrane Register of Controlled Trials for all original articles up to January 2006 and up to November 2005 for systematic reviews. They also searched unpublished industry and US Food and Drug Administration (FDA) records. The search yielded 216 controlled trials and cohort studies and 2 systematic reviews on benefits and harms of drugs used in the US to treat diabetes orally.
The analysis gave up the following results:
- Evidence from clinical trials tied to major endpoints such as cardiovascular mortality was inconclusive.
- This meant the review had to be limited to evidence pertaining to intermediate endpoints only.
- The thiazolidinediones, metformin, and repaglinide improved glycemic control as well as the sulfonylureas.
- Nateglinide and alpha-glucosidase inhibitors may have slightly weaker effects, on the evidence of indirect comparisons of placebo-controlled trials.
- Thiazolidinediones were the only drugs that increased “good cholesterol” (HDL) and decreased “bad cholesterol” (LDL).
- Metformin reduced LDL while the remaining drugs had no obvious effects on LDL.
- Most of the drugs, apart from metformin, increased body weight by between 1 and 5 kg.
- Sulfonylureas and repaglinide were linked to increased risk of hypoglycemia.
- Thiazolidinediones were linked to increased risk of heart failure.
- Metformin was linked to increased risk of gastrointestinal problems.
- Patients taking metformin were no more likely to have lactic acidosis without side effects than patients on other drugs.
The authors said their study was limited by the lack of data on major endpoints and some studies were inconsistent in their reporting and descriptions of adverse events apart from hypoglycemia. They also said some side effects that were not recorded in trials or observational studies may have been overlooked.
Consumer reaction to the study is very favorable, as expressed by Gail Shearer, project director of Consumer Reports Best Buy Drugs:
“This is truly significant information for the millions of people with diabetes struggling to control their disease, but also struggling with the high cost of their medications.”
“The evidence shows that lower-cost, older medicines work just as well for most people,” added Shearer.
“Systematic Review: Comparative Effectiveness and Safety of Oral Medications for Type 2 Diabetes Mellitus.”
Shari Bolen, Leonard Feldman, Jason Vassy, Lisa Wilson, Hsin-Chieh Yeh, Spyridon Marinopoulos, Crystal Wiley, Elizabeth Selvin, Renee Wilson, Eric B. Bass and Frederick L. Brancati.
Annals of Internal Medicine, 18 September 2007: Volume 147 Issue 6.
Click here for early online issue of the full Article.
Written by: Catharine Paddock
Writer: Medical News Today