Pain management and patient education interventions to increase physical activity in people with intermittent claudication (PrEPAID): a feasibility randomised controlled trial in the United Kingdom

Objectives To explore the feasibility and acceptability of pain management (transcutaneous electrical nerve stimulation (TENS)) and patient education (PE) to increase physical activity in people with peripheral arterial disease and intermittent claudication (IC). Design Feasibility randomised controlled trial with embedded process evaluation. Setting One secondary care UK vascular centre. Participants 56 community-dwelling adults with a history of stable IC and ankle-brachial pressure index ≤0.9 were recruited via claudication clinics. Interventions Participants randomised to 6 weeks of: TENS+PE, TENS, Placebo TENS+PE or Placebo TENS. PE was a 3-hour workshop plus three follow-up phone calls. The TENS machine was worn during walking (TENS: 120 Hz, 200 μs, intensity ‘strong but comfortable’; Placebo TENS: intensity below sensation threshold). Outcomes Primary feasibility outcomes included rates of recruitment, retention and adherence. Acceptability of the intervention and trial procedures was explored with semistructured interviews. Measures of walking capacity, walking behaviour, quality of life, disease perception and pain were recorded at baseline, end of intervention (6 weeks) and follow-up (3 months). Results 56 participants were randomised from 95 who completed baseline screening. Of the 39 excluded, 97% (38/39) had >20% variability in absolute claudication distance. All participants received their allocated intervention. Outcome completion was 91% at 6 weeks and 80% at 3 months. Attendance at group education was 96% with 63% taking follow-up phone calls. Compliance with TENS was 70% according to participant-completed logs. Interviewed participants (n=9) were generally positive about the acceptability of the interventions and trial procedures; however, experience of TENS use was mixed. Some participants were dissatisfied with the size of the device and electrode wires. Conclusions The PrEPAID (Pain management and Patient Education for Physical Activity in Intermittent claudication) trial was feasible to run; however, 40% of potential participants were excluded at screening due to issues of research fidelity rather than participant suitability or willingness to participate. A future definitive trial should consider a revised primary outcome measure and smaller wireless TENS machines. Trial registration number ClinicalTrials.gov, NCT03204825. Registered on 2 July 2017. Trial funding Chief Scientist Office, Scottish Government. Translational grant award (TCS/16/55).