Which factors predict outcome from specialist physiotherapy for functional motor disorder? Prognostic modelling of the Physio4FMD intervention

Abstract

Objectives

Physiotherapy is considered part of first line treatment for functional motor disorder (FMD) although not all patients benefit. Predictors of treatment outcome may help to inform triage decisions. We aimed to determine which baseline variables predicted treatment outcome in the pragmatic multicentre Physio4FMD randomised controlled trial of specialist physiotherapy for FMD.

Methods

Participants randomised to the specialist physiotherapy arm of the trial were included in the analysis. Treatment outcome was dichotomised into improvement vs no improvement, based on two measures, Short Form 36 Physical Functioning (SF36 PF) and participant-rated Clinical Global Impression Scale of Improvement (CGI-I). Predictors of outcome were selected from baseline variables. Univariate logistic regression was used to calculate the odds ratio of improvement for each variable. Variables associated with improvement at p < 0.1 were considered for inclusion in a multiple logistic regression model.

Results

A greater perception of having control over recovery predicted improvement on the CGI-I (OR 1.18, 95 % CI 1.07, 1.31). Predictors of lack of improvement were an increased perception of the permanence of symptoms, predicting lack of improvement on the SF36 PF (OR 0.91, 95 % CI 0.84, 0.99) and older age, predicting lack of improvement on the CGI-I (OR 0.97, 95 % CI 0.95, 0.998).

Conclusions

Age and perceptions of symptom control were weak predictors of outcome from specialist physiotherapy. In contrast, a number of factors commonly believed to predict poorer treatment response, including illness duration and levels of pain and fatigue, were not related to the outcomes measured in this study.