Studies presented this past June at the American Diabetes Association's 58th Annual Scientific Sessions suggest that two treatment breakthroughs may be in the offing for the millions with diabetes. First, insulin therapy without injections may soon become a reality. And second, researchers are taking a closer look at the role postmenopausal hormone replacement therapy (HRT) may have in preventing type 2 diabetes and related complications.
A portable, aerosol system that delivers insulin in the form of a dry powder directly into the lungs through the mouth has been shown to provide blood glucose control comparable to that traditionally obtained through multiple daily insulin injections. About the size of a flashlight, the new system is expected to promote patient adherence to insulin therapy because it's associated with far less discomfort and inconvenience than injections. The new aerosol inhaler, under development, has performed well in two multicenter clinical studies.
In the first study, 70 subjects with type 1 diabetes were recruited from 10 sites and randomly assigned to either standard insulin therapy (continuing with their prescribed regimen of two to three injections daily) or inhaled insulin therapy (one to two inhalations of insulin before each meal plus one injection of slow-acting insulin at bedtime) for three months. Aiming for a premeal glucose level of 100 to 160 mg/dL, subjects checked their blood sugar levels four times daily and met with researchers weekly for evaluation and adjustments to improve blood glucose control.
Blood glucose control improved in both groups. In addition, glycosylated hemoglobin levels (HbA1c), a measure of long-term glucose control, which had averaged 8.5% at baseline for both groups, was strikingly similar in both groups after three months: 7.7% in the group using standard insulin therapy and 7.8% in the group using inhaled insulin therapy.
In the second study, 51 subjects with type 2 diabetes were recruited from 10 sites and randomly assigned to the same treatment regimens and evaluation procedures designed for the first study. Again, blood glucose control improved in both groups and HbA1c levels improved by the same amount. At baseline, the group using standard insulin therapy averaged 7.8%, compared with 8.7% for the group using inhaled insulin therapy. In both groups, levels dropped by 0.7%.
No significant adverse effects were observed in either study. The new system is expected to obtain FDA approval within five years.
On another treatment front, new studies suggest that postmenopausal HRT not only may help prevent type 2 diabetes in some women but also may reduce the risk of related complications in those who have developed the disease. Kaiser Permanente of Oakland, California, has surveyed medical records of more than 14,600 women who have diabetes and are over the age of 50. Results suggest that the respondents who take HRT have significantly better blood glucose control (lower levels of HbA1c) than those who don't: 8% versus 8.5% in non-Hispanic Caucasians; 8.3% versus 8.9% in Hispanics; 8.2% versus 8.7% in African Americans, and 8.2% versus 8.9% in Asians or Pacific Islanders.
Meanwhile, a medical record review conducted by researchers at the University of Wisconsin in Milwaukee found that women who do not take HRT are nearly five times as likely to develop type 2 diabetes as those who do. The Milwaukee study involved 418 women who had been postmenopausal for at least five years: 237 had used HRT continuously since menopause; 141 had never used HRT; and 40 had used it at some point, though not continuously since menopause. After researchers controlled for other diabetes risk factors such as age, obesity, socioeconomic status, ethnicity, family history, and number of pregnancies, women not using HRT were still 4.8 times as likely to develop diabetes as those using HRT.
Sources: American Diabetes Association, news releases, June 14 an June 16, 1998