Further evidence for a high incidence of nocturnal hypoglycaemia in IDDM: no effect of dose for dose transfer between human and porcine insulins.

We tested the hypothesis that transfer from porcine to human insulin causes a fall in nocturnal blood glucose and an increase in the frequency of hypoglycaemic episodes. Twenty IDDM patients (age 19-55, duration 3-36 years) used Velosulin and Insulatard twice daily for 12 weeks, double-blinded to species (human (H) or porcine (P)) in a randomized crossover study. Species was changed after 4 weeks' run-in and 4 weeks later, with insulin doses unchanged on transfer. Ten patients underwent each sequence (H/P/H or P/H/P) and were admitted on the first and eighth night after transfer for hourly blood glucose measurement (22.00-07.00). Biochemical hypoglycaemia (<3.5 mmol l(-1)) was observed on 39 of the 80 patient-nights studied (48.75%). The number of episodes were similar during each night (H1 8, H8 10, P1 10, P8 11, p = 0.83). Total reported symptomatic episodes (H 51 vs P 73, p = 0.85), total HbA1 (H 9.8 +/- 0.3%, P 10.0 +/- 0.3%, p = 0.32) and daily insulin doses (H 0.63 +/- 0.04 units kg(-1) day(-1) vs P 0.63 +/- 0.05 units kg(-1) day(-1), p = 0.54) were not different. Despite an apparent fall in blood glucose levels from night 1 to 8 on transfer to human (AUC 82.3 +/- 7.8 vs 61.4 +/- 5.3 mmol.h l(-1), p < 0.05) but not porcine insulin (AUC 70.7 +/- 7.2 vs 70.1 +/- 7.5 mmol.h l(-1), p = 0.74), there was no difference when all 4 nights were considered together (p = 0.30). We conclude that dose for dose transfer to human insulin does not increase numbers of episodes of nocturnal or reported hypoglycaemia.