Pre-meal inhaled insulin lowers HbA1c levels more effective than rosiglitazone

Inhaled insulin (Exubera, Pfizer/Sanofi-Aventis) could be an effective therapy and alternative to rosiglitazone (Avandia, GlaxoSmithKline) for individuals who are early into the course of type 2 diabetes, according to a study published in Diabetes Care.

The multicenter trial involved 145 individuals whose type 2 diabetes was not controlled adequately by diet and exercise alone (HbA_1c, 8%–11%). The patients' mean age was 54 and their mean baseline HbA_1c level was 9.5%.

Each subject was randomized to 3 months of treatment with either inhaled insulin (INH) before meals (n=76) or rosiglitazone 4 mg twice a day (n=69), in conjunction with a diet and exercise program. Seventy-one and 63 patients from each treatment group, respectively, completed the study. The primary end point was the percentage of patients achieving HbA_1c <8.0% at 12 weeks or at the time of discontinuation.

The favorable inhaled insulin results were also similar at the American Diabetes Association-recommended HbA_1c value of <7.0% (44% vs 17.9%; adjusted OR, 4.43; 95% CI, 1.94–10.12) and the American Association of Clinical Endocrinologists-recommended HbA1c value of #6.5% (28% vs 7.5%; adjusted OR, 5.34; 95% CI, 1.83–15.57).

The absolute reduction in HbA_1c at Week 12 was greater in the INH group (–2.3% vs –1.4%; adjusted treatment group difference, –0.89%; 95% CI, –1.23 to –0.55), with mean final HbA_1c values of 7.2% and 8.0% for INH and rosiglitazone, respectively.

"To our knowledge, this represents the only demonstration that American Diabetes Association goals for glycemic control can be achieved in many type 2 diabetes patients using only a rapid-acting insulin," the authors stated.

Noting that rosiglitazone may take 18 or more weeks to achieve peak glucose-lowering activity, the authors stated that it "cannot be ruled out that a longer study duration may have resulted in greater glucose lowering in the rosiglitazone arm."

Hypoglycemic episodes occurred significantly more often in the inhaled-insulin group than in the rosiglitazone group (0.7 vs 0.05 episodes per patient-month, respectively; risk ratio, 14.72; 95% CI, 7.51–28.83). However, no severe hypoglycemic episodes were reported by any patients in the INH group.

SOURCE DeFronzo RA, Bergenstal RM, Cefalu WT, et al. Efficacy of inhaled insulin in patients with type 2 diabetes not controlled with diet and exercise. Diabetes Care. 2005;28:1922–1928.