The lung as an alternative route of delivery for insulin in controlling postprandial glucose levels in patients with diabetes

Study objectives: To determine the efficacy of the lung as an alternative r out-e of delivery for insulin in controlling glucose below diabetic levels (11.2 mmol/L) 2 h after the ingestion of a meal in patients with type 2 dia betes mellitus, Design: Single-blinded, nonrandomized, placebo-controlled pilot study consi sting of two visits. Setting: A primary care facility. Patients: Seven patients with type 2 diabetes mellitus. Interventions: On the first study visit, fasting glucose levels were normal ized. Then, patients inhaled 1.5 U/kg insulin by aerosol into the lungs 5 m ill before ingesting a test meal. On the second visit, patients inhaled pla cebo aerosol 5 min before ingesting the same meal. On both visits, plasma s amples were collected and analyzed for glucose levels for 3 h during the po stprandial state. Measurements and results: No one coughed after inhalation of insulin aeroso l or demonstrated hypoglycemia. During the postprandial period, glucose lev els were significantly lower at 20 min (5.12 +/- 1.08 mmol/L,), 1 h (7.87 /- 0.73 mmol/L), 2 h (8.05 +/- 1.24 mmol/L) and 3 h (7.50 +/- 1.43 mmol/L) following inhalation of insulin than when the placebo was used. Data for th e placebo were 10.36 +/- 1.23 mmol/L at 20 min, 14.0 +/- 1.68 mmol/L at 1 h , 16.18 +/- 1.45 mmol/L at 2 h, and 14.37 +/- 2.11 mmol/L at 3h (for all co mparisons, p < 0.05), On the insulin visit, glucose levels were < 11.2 mmol /L, 2 h after the meal in sis of seven patients. None attained this level a t the placebo visit. In addition, glucose levels were within the normal pos tprandial range of < 7.84 mmol/L, in foul. of seven patients 2 tl after eat ing on the insulin visit. Conclusions: These results suggest that, once plasma glucose levels are nor malized, postprandial glucose levels can be maintained below diabetic level s by delivering 1.5 U/kg insulin into the lungs 5 min before the ingestion of a meal.