Description

A 3 centre, 3-arm, parallel group, open label, stratified randomized controlled trial design is used with a 1:1:1 allocation ratio and blinding of outcome assessors.

Primary Objectives:

1. To evaluate the efficacy of Tab. Nebivolol 10 mg/ day (or maximally tolerated dose) compared to standard care (pain modulators alone) on mean nerve action potential at week 24.
2. To evaluate the efficacy of Tab. Nebivolol 10 mg/day (or maximally tolerated dose) compared to a combination of lipoic acid 600 mg/d plus epalrestat 150 mg/day at week 24 on mean nerve action potential at week 24.

Secondary Objectives: 1. To compare the intra-epidermal nerve fibre density (IENFD), high-sensitivity C-reactive protein (hsCRP) and quantify GAP-43 (neuromodulin) in a randomly selected sample (stratified by sex and baseline disease severity) of 20% patients from each from the 3 arms pre and post intervention: corneal nerve fiber length and density using confocal microscopy in all patients in the 3 arms at week 24.

2. To compare the electrical conductance (mean µSiemens) using Sudoscan between the nebivolol arm versus standard care alone and the nebivolol arm versus alpha-lipoic acid plus epalrestat arm at week 24.

3.To compare mean hsCRP levels in a randomly selected sample of 20% of patients between the 3 arms at 6 months and change in mean hsCRP levels from baseline to 6 months in the intervention arm.

4) To compare mean GAP-43 levels in a randomly selected sample of 20% of patients.

5) To compare mean intra-epidermal nerve fiber density (IENFD) in a randomly selected sample of 20% of patients.

6)To compare corneal nerve fiber length and density in a randomly selected sample of 20% of patients.

7) Electrical conductance (mean µSiemens) using Sudoscan between the nebivolol arm versus standard care alone and the nebivolol arm versus alpha-lipoic acid plus epalrestat arm at week 24.

8) Mean nerve conduction velocity - nebivolol versus standard care and nebivolol versus alpha-lipoic acid+epalrestat arms at week 24.

9) Compare general quality of life measured using the EQ-5D-5L questionnaire at week 24.

10) Cost-effectiveness analysis between the three treatment arms with nerve conduction study parameters and numerical pain rating scores as outcome measures at week 24.

Patients will be randomized into three of the following arms- Arm 1 - Tab. Nebivolol 2.5 mg/day from baseline to week 2, up-titrated to 5 mg/day at week 2 and from 5 mg/ day to 10 mg/day from week 4 to week 24 after an ECG at week 4 plus standard care pain modulating drugs.

Arm 2 - Cap. Alpha-Lipoic Acid 600 mg/ day plus Tab. Epalrestat 150 mg/day from baseline to week 24 plus standard care pain modulating drugs.

Arm 3 - Standard pain modulating treatments per physician's discretion. This will likely be a monotherapy or combinations of pregabalin, duloxetine or amitriptyline.

Only patients with stable glycemic control for the past 3 months will be enrolled. During screening if patients has uncontrolled diabetes, the doses of the diabetes treatments will be optimized, add-on treatments will be commenced and if needed medications for risk factor control such as statins and anti-hypertensives will be added on. All patients will receive dietary counselling for medical nutrition therapy (MNT) and guideline-based exercise regimen advised. Glycemic control and adherence to all standard care treatments will be periodically assessed at follow-ups and encouraged. Rescue Medications - Tab. Paracetamol 1 gram up to 4 grams over a 24 hour period will be added in cases of intractable pain.