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. © 1997 by John Wiley & Sons, Ltd.