The study involved 299 diabetic patients who previously had to make at least two daily insulin injections to keep blood sugar under control. Half the participants switched to inhaled dry-powder insulin (Exubera) before each meal and a single injection of ultralente insulin at bedtime for 6 months. The others continued to receive all of their required insulin by injection.

Results showed that blood sugar levels improved to a similar degree in the inhaled and subcutaneous insulin groups. However, more patients in the inhaled insulin group (47 percent) than in the subcutaneous insulin group (32 percent) achieved target glucose levels.

Episodes of excessively low glucose occurred slightly less often in the inhaled insulin group, and there were no differences in severe adverse events, the investigators report in the journal Diabetes Care. There have been concerns that inhaled insulin affects the lungs, but there were "no major differences in the comprehensive pulmonary testing done during the study" Hollander said. "Safety concerns are a paramount concern when giving a drug like insulin in a totally new way," she added

Nevertheless, cough of mild-to-moderate severity was reported more frequently in the inhaled insulin group, but it occurred less often as the study progressed.

"Patients liked the inhaled insulin better," Hollander noted. "There were significant differences in the quality of life testing between the two groups."

In addition, "patients treated with inhaled insulin gained significantly less weight than the patients treated with injected insulin." Further long-term studies of inhaled insulin are currently underway.