The long-term benefits of good glycemic control are well established. The aim of this proof-of-concept study was to determine whether glycemic control can be improved in patients with type 2 diabetes mellitus with suboptimal glycemic control, despite therapeutic dosages of oral antihyperglycemic agents (OHAs), by the addition of preprandial inhaled insulin (INH).
Sixty-eight patients with inadequately controlled type 2 diabetes mellitus (glycosylated hemoglobin, 8.1%-11.9%), despite therapy with a sulfonylurea and/or metformin, were randomized to receive INH in addition to their prestudy OHA therapy (INH + OHA group, n = 32) or to continue taking their prestudy OHA alone for 12 weeks (OHA group, n = 36). Premeal INH doses were delivered in 1 to 2 inhalations of 1-mg or 3-mg doses (equivalent to 3 IU and 9 IU, respectively, of subcutaneously injected regular insulin).
At week 12, there was a significantly greater reduction in glycosylated hemoglobin for the INH + OHA cohort (mean reduction, −2.3%) compared with the OHA-only cohort (mean reduction, −0.1%, P<.001). Eleven patients (34%) receiving INH + OHA achieved glycosylated hemoglobin values of less than 7%, compared with none taking OHAs only. Fasting plasma glucose improved significantly more in the INH + OHA group compared with the OHA-only group (−60.69 mg/dL (−3.37 mmol/L] greater reduction, P<.001), and the postprandial increase in glucose was significantly lower in those patients receiving INH + OHA (P = .02). There was 1 report of severe hypoglycemia in the INH + OHA group (home blood glucose, 54 mg/dL [3.0 mmol/L]) and a greater increase in body weight. Pulmonary function was unchanged in both groups.
The addition of preprandial INH to existing OHAs improves glycemic control without the need for injections in patients with type 2 diabetes mellitus failing to achieve satisfactory control with OHAs alone.