The Utah Early Neuropathy Scale (UENS) is a brief, validated exam scale focused on injury to small diameter nociceptive fibers. Twenty-four of 42 possible points are related to measurement of length dependent loss of pin sensation in legs and feet. While the UENS has been accepted as a standard clinical measure for diagnosis of small fiber neuropathy, its utility as a primary outcome measure in clinical trials has not been evaluated. Here we report natural history progression of the UENS. In an NIDDK DP3 single center study, 190 patients with diabetes were screened for neuropathy using Toronto criteria, then 83 found to have neuropathy were followed longitudinally at 9-month intervals for up to 27 months using a variety of clinical and ancillary measures, including the UENS. Among those with neuropathy, baseline UENS score significantly correlated with scores of symptom questionnaires including the Norfolk Quality of Life-Diabetes Neuropathy (NQoL-DN) and the NTSS-6; with nerve conduction study measures including sural sensory amplitude, peroneal amplitude and proximal conduction velocity; with intraepidermal nerve fiber density (IENFD) from distal thigh and distal leg 3m punch skin biopsies; but not with confocal corneal microscopy measures of nerve fiber length and density. Overall, 75 participants were followed for 9 months, and 56 for at least 18 months for a total of 149 9-month segments. UENS worsened (increased) 1.08 (+/- StDev 3.51) points per 9-month segment overall. For those followed at least 18 months, there was a 2.2 (+/-4.1) point increase over this period. Change in UENS significantly correlated with change in NQoL-DN and IENFD, among other measures. The UENS is an objective, responsive, validated clinical instrument for which a linear natural progression slope can be measured, and would be an appropriate primary endpoint in small fiber neuropathy clinical trials.
J. Singleton: None. P.E. Hauer: None. C. Revere: None. S.C. Foster-Palmer: None. A.B. Aperghis: None. A. Smith: Consultant; Self; Alexion Pharmaceuticals, Inc., Disarm, Regenesis.
National Institutes of Health (DP3DK104394)