In patients with type 2 diabetes, insulin therapy is commonly initiated with either a single dose of basal insulin or twice-daily premixed (basal plus prandial) insulin despite no widely accepted recommendation. We compared the glycaemic control, as measured by a change in HbA1c, of intensive mixture therapy (IMT), a basal plus prandial regimen using insulin lispro mixture 50/50 (50% lispro and 50% NPL) before breakfast and lunch and insulin lispro mixture 25/75 (25% lispro and 75% NPL) before dinner, vs. once-daily insulin glargine therapy, while continuing patients on oral antidiabetes medications.
Following inadequate glycaemic control (HbA1c 1.2-2.0 times the upper limit of normal) and at least 2 months of two or more oral antidiabetes agent therapy, 60 insulin-naïve patients with type 2 diabetes were randomized to one of the insulin regimens for 4 months with crossover to the alternative regimen for an additional 4 months. Glycaemic goals were preprandial blood glucose <120 mg/dl (6.7 mmol/l) and 2-h postprandial blood glucose <180 mg/dl (10.0 mmol/l). The insulin dose was optimized by investigators without forced titration.
Mean prestudy (baseline) HbA1c for all patients was 9.21 +/- 1.33% (+/-s.d.). IMT compared to glargine resulted in both a lower endpoint in HbA1c (7.08 +/- 0.11% vs. 7.34 +/- 0.11%; p = 0.003) and a greater change in HbA1c from pretherapy (-1.01 +/- 0.10% vs. -0.75 +/- 0.10%; p = 0.0068). Forty-four per cent of patients receiving IMT and 31% of patients receiving insulin glargine achieved HbA1c < or = 7%. Two-hour postprandial glucose values (for all three meals) and predinner glucose values were significantly less with IMT than with insulin glargine (p = 0.0034, 0.0001, 0.0066 and 0.0205). Overall hypoglycaemia throughout the complete treatment period was infrequent (IMT vs. Glargine: 3.98 +/- 4.74 vs. 2.57 +/- 3.22 episodes/patient/30 days, p = 0.0013), and no severe hypoglycaemia was observed during the study with either therapy. There was no difference in nocturnal hypoglycaemia between the two therapies. The mean insulin dose at the end of therapy was greater for IMT than for once-daily insulin glargine (0.353 +/- 0.256 vs. 0.276 +/- 0.207 IU/kg, p = 0.0107).
In combination with oral antidiabetes agents, multiple daily injections of a basal plus prandial insulin IMT regimen (using premixed insulin lispro formulations) resulted in greater improvements and a lower endpoint in HbA1c compared with a basal-only insulin regimen. IMT also resulted in improved postprandial blood glucose control at each meal and enabled administration of a greater daily dose of insulin, which most likely contributed to these lower HbA1c measures. This greater reduction in HbA1c with IMT is accompanied by a small increased occurrence of mild hypoglycaemia but without any severe hypoglycaemia. Greater consideration should be given to initiating insulin as a basal plus prandial regimen rather than a basal-only regimen.