The effect of 8 years of strict glycaemic control on peripheral nerve function in IDDM patients: the Oslo Study

Abstract

SummaryWe have investigated the effect of long-term strict glycaemic control on peripheral and autonomic nerve function in 45 IDDM patients (age 18-42 years, diabetes duration 7-23 years) without clinical signs of neuropathy or other neurological disease. They were randomly assigned to treatment either with continuous insulin infusion, multiple injections (4-6 times daily), or conventional treatment (twice daily) for 4 years and followed prospectively for 8 years. Motor and sensory nerve conduction velocities were measured at the start and after 8 years. Autonomic nerve function tests were performed only once, after 8 years. A significant reduction of nerve conduction velocity was observed during 8 years in patients with mean HbA1 more than 10% (n = 12, group mean 10.9%, range 10.1-13.2%) compared to patients with HbAI less than 10% (n = 33, group mean 9.0 %, range 7.5-9.9 %). Change of motor nerve conduction velocity in the peroneal nerve was: -4.8 + 4.9 (SD) vs -2.2 + 5.3 m/s (p < 0.01). Change of motor nerve conduction velocity in the posterior tibial nerve was: -6.8 + 5.7 vs-3.9 +_ 5.1 m/s (p < 0.05). No significant changes were observed in the ulnar nerve. Change of sensoric nerve conduction velocity in the sural nerve was: -8.9 + 8.0 vs -4.6 + 5.3 m/s (p < 0.05). Multiple regression analysis showed that a change in HbA1 of 1% resulted in a 1.3 m/s change in nerve conduction velocity during 8 years. A significantly lowered heart-rate variation during deep breathing (p < 0.05) and heart-rate response to standing (p < 0.01) was found in patients with HbA1 more than 10 % compared to patients with HbA1 less than 10 %. This study confirms that the long-term lowering of blood glucose retards the deterioration in nerve conduction velocity observed in the diabetic nerve. [Diabetologia (1994) 37: 579-584]

Recent developments in the assessment of efficacy in clinical trials of diabetic neuropathy

“…In the Diabetic Control and Complications Trial (type 1 diabetes), the sural and peroneal nerve velocities in the conventionally treated group diminished by 0.56 and 0.54 m/s/y, respectively, over 5 years [27]. In a prospective 8-year study of 45 type 1 diabetic patients, a 1% rise in hemoglobin A 1c was associated with a 1.3-m/s decrease in maximal nerve conduction [28]. In patients with type 2 diabetes, a lower rate of decline was observed in a 10-year natural history study of 133 patients with newly diagnosed type 2 diabetes, where NCV deteriorated by 0.39 m/s/y in the sural and by 0.3 m/s/y in the peroneal nerves [29].…”

Visual evoked potentials in young persons with newly diagnosed diabetes: a long‐term follow‐up

“…Moreover, although many experimental and clinical data indicate that chronic hyperglycaemia is implicated in the pathogenesis of diabetic neuropathy (Amthor et al 1994), there are conflicting results about the relation between the quality of metabolic control and the degree of visual evoked potential (VEP) response (Cirillo et al 1984, Mariani et al 1990, MacRury et al 1991, Ziegler et al 1994.…”

Therapie der diabetischen Polyneuropathie

“…Aus diesen kann man schließen, dass bei noch nicht von einer Neuropathie betroffenen Typ-1-Diabetikern eine deutlich verbesserte Stoffwechseleinstellung das Neuauftreten einer Neuropathie, gemessen an den Ergebnissen neurologischer Untersuchungen, autonomer Abb. 1 …”