Clinical trials for diabetes drugs should measure outcomes important to patients

Sep 27 2007

Most clinical trials for new diabetes drugs do not consider the impact medication will have on a patient's quality of life or other outcomes that are important to patients, such as the risk of developing complications associated with diabetes, according to a Mayo Clinic commentary in the current issue of The Lancet.

Rather, drug trials focus on the effect of a particular medication on blood sugar levels. The result is smaller, shorter and cheaper trials that lead to more drug choices more quickly, but are not necessarily better or safer for patients.

“The apparent benefits of these trials are a mirage and the apparent savings represent false economy,” writes Victor Montori, M.D., an endocrinologist at Mayo Clinic, along with Gunjan Gandhi, M.D., of Mayo Clinic, and Gordon Guyatt, M.D., of McMaster University in Canada. “Any savings are quickly overwhelmed by expenses associated with potentially ineffective, or even harmful, expensive therapies and the incremental costs of treating the harms these interventions might cause. Patients and society may end up paying dearly for medications that cause more harm than good.”

The medical community is increasingly aware of the need to engage patients with chronic conditions in decisions about their care. For example, clinicians and patients need to know the extent to which diabetes medications can help patients feel better and live longer. Despite this need, only one in five randomized trials in diabetes published in top medical journals measured the effect of drugs on quality of life and on the risk of complications associated with diabetes, such as death, heart attack, stroke, amputation, blindness and dialysis. Ongoing trials do not promise much more, the author states.

Dr. Montori and colleagues call for clinical trials that consider and measure the impact of diabetes medications on outcomes that are important to patients.

“The medical community should insist that we invest the resources needed to do trials that ascertain the effect of interventions on patient-important outcomes,” the authors state. “This policy will prevent the premature dissemination of therapies that ultimately prove harmful, facilitate patients' participation in decision making, and speed the day when we can confidently offer safe treatments that can provide important benefit to patients with diabetes.”

In summary, the authors say:

1. Diabetes medications have been approved without requiring proof of reducing the risk of complications associated with diabetes, such as heart attack, stroke, amputation, blindness and kidney dialysis.
2. The majority of diabetes trials focus on the ability of medications to reduce blood sugar, not on outcomes that matter to patients.
3. Diabetes medications may reduce the risk of complications, but we do not know this with confidence.
4. The focus should shift from getting new drugs to market to testing the effect of diabetes medications against outcomes important to patients.

Dr. Montori is a lead investigator with the Knowledge and Encounter Research Unit at Mayo Clinic. His research team seeks to improve the care and outcomes of patients with diabetes by studying ways to promote health care decisions that are more consistent with research findings and the values and preferences of informed patients.