Lee Silverman Voice Treatment versus standard speech and language therapy versus control in Parkinson's disease: preliminary cost-consequence analysis of the PD COMM pilot randomised controlled trial

Abstract

Background: The PD COMM pilot randomised controlled trial compared Lee Silverman Voice Treatment (LSVT® LOUD) with standard NHS speech and language therapy (SLT) and a control arm in people with Parkinson's disease (PwPD) with self-reported problems with voice or speech. This analysis compares costs and quality of life outcomes between the trial arms, and considers the validity of the alternative outcome measures for economic evaluations.

Methods: A comparison of costs and outcomes was undertaken alongside the PD COMM pilot trial involving three arms: LSVT® LOUD treatment (n = 30); standard NHS SLT (n = 30); and a control arm (n = 29) excluded from receiving therapy for at least 6 months after randomisation unless deemed medically necessary. For all trial arms, resource use and NHS, social care and patient costs and quality of life were collected prospectively at baseline, 3, 6, and 12 months. Total economic costs and outcomes (EQ-5D-3L, ICECAP-O) were considered over the 12-month follow-up period from an NHS payer perspective. Quality of life measures for economic evaluation of SLT for people with Parkinson's disease were compared.

Results: Whilst there was no difference between arms in voice or quality of life outcomes at 12 months, there were indications of differences at 3 months in favour of SLT, which need to be confirmed in the main trial. The estimated mean cost of NHS care was £3288 per patient per year for the LSVT® LOUD arm, £2033 for NHS SLT, and £1788 for the control arm. EQ-5D-3L was more strongly correlated to voice impairment than ICECAP-O, and was sensitive to differences in voice impairment between arms.

Conclusions: The pilot did not identify an effect of SLT on disease-specific or economic outcomes for PwPD at 12 months; however, there appeared to be improvements at 3 months. In addition to the sample size not powered to detect difference in cost-consequence analysis, many patients in the control arm started SLT during the 12-month period used for economic analysis, in line with the study protocol. The LSVT® LOUD intervention was more intense and therefore more costly. Early indications suggest that the preferred economic outcome measure for the full trial is EQ-5D-3L; however, the ICECAP-O should still be included to capture a broader measure of wellbeing.

Trial registration: International Standard Randomised Controlled Trial Number Register: ISRCTN75223808. Registered 22 March 2012.

Keywords: Cost-consequence analysis; Parkinson’s disease; Pilot randomised controlled trial; Speech and language therapy.