479-P: Natural Course of Declining Nerve Function during the First 10 Years of Well-Controlled Type 2 Diabetes

There is a lack of evidence on the long-term changes of nerve function in individuals with type 2 diabetes (T2D) compared to those with normal glucose tolerance (NGT). Therefore, we assessed motor and sensory nerve conduction velocities (MNCV, SNCV), sensory nerve action potentials, vibration perception threshold (VPT) and thermal detection threshold of lower extremities in 45 individuals with T2D (known diabetes duration [mean±SD]: 164±95 days) and NGT from the German Diabetes Study (GDS) at baseline (BL) and 5-year follow-up. Individuals were matched pairwise for age (T2D/NGT: 52.9±10.4/52.9±10.3 years) and sex (64/64% male). In addition, 103 individuals with T2D were followed over 10 years. At BL, 1/6 indices was lower in T2D vs NGT (peroneal MNCV: 45.6±4.0 vs 47.2±2.8 m/s; P<0.05). After five years, one index deteriorated in T2D (peroneal MNCV: 45.3±4.1 vs 43.5±3.8 m/s) and one in NGT (malleolar VPT: 1.29±1.88 vs 2.25±3.06 µm) (all P<0.05). After adjustment for BL values and pairwise matching, nerve function similarly declined over the first five years in T2D and NGT (e.g. Δperoneal MNCV; figure). A comparable deterioration was observed in individuals with T2D over 10 years (figure). Parallel decline in small and large fiber function in both NGT and well controlled T2D indicates that the main events leading to impaired nerve function in well controlled T2D might occur earlier than previously assumed.