COgnitive behavioural therapy versus standardised medical care for adults with Dissociative non-Epileptic Seizures (CODES): statistical and economic analysis plan for a randomised controlled trial

Abstract

BackgroundDissociative seizures (DSs), also called psychogenic non-epileptic seizures, are a distressing and disabling problem for many patients in neurological settings with high and often unnecessary economic costs. The COgnitive behavioural therapy versus standardised medical care for adults with Dissociative non-Epileptic Seizures (CODES) trial is an evaluation of a specifically tailored psychological intervention with the aims of reducing seizure frequency and severity and improving psychological well-being in adults with DS. The aim of this paper is to report in detail the quantitative and economic analysis plan for the CODES trial, as agreed by the trial steering committee.MethodsThe CODES trial is a multicentre, pragmatic, parallel group, randomised controlled trial performed to evaluate the clinical effectiveness and cost-effectiveness of 13 sessions of cognitive behavioural therapy (CBT) plus standardised medical care (SMC) compared with SMC alone for adult outpatients with DS.DiscussionThe objectives and design of the trial are summarised, and the aims and procedures of the planned analyses are illustrated. The proposed analysis plan addresses statistical considerations such as maintaining blinding, monitoring adherence with the protocol, describing aspects of treatment and dealing with missing data. The formal analysis approach for the primary and secondary outcomes is described, as are the descriptive statistics that will be reported. This paper provides transparency to the planned inferential analyses for the CODES trial prior to the extraction of outcome data. It also provides an update to the previously published trial protocol and guidance to those conducting similar trials.Trial registrationISRCTN registry ISRCTN05681227 (registered on 5 March 2014); ClinicalTrials.gov NCT02325544 (registered on 15 December 2014).

The experience of trial participation, treatment approaches and perceptions of change among participants with dissociative seizures within the CODES randomized controlled trial: A qualitative study

“…More women than men were interviewed to reflect the higher prevalence of DS among women in the CODES study [ 22 ] and the population with DS more widely. The majority (20/22) of participants randomized to receive CBT who were interviewed here attended at least nine CBT sessions and were therefore classified as compliant with the DS-specific CBT in the study [ 23 ]. Those interviewees allocated to CBT + SMC attended a median of 3.5 SMC sessions (range: 0–10 sessions), while those patients allocated to SMC-alone attended a median of 4 SMC sessions (range: 2–6 sessions).…”

Outcome of patients with psychogenic nonepileptic seizures with limited resources: A longitudinal study

“…Determining the long-term outcome of PNES across borders and cultures has important clinical implications. For example, a recent well-designed clinical trial on 38 patients [6], with relatively a short follow up period (16 weeks), showed that the best current practice (combined CBT with sertraline) resulted in 59.3% seizure reduction which was significantly better compared with that in the treatment as usual group. A recent metaanalysis synthesized data from 13 studies with a total of 228 patients with PNES [15]; results showed that 47% of the patients with PNES were seizure-free upon completion of a psychological intervention.…”

“…However, access to resources are limited in Iran and many other developing countries compared to that in the Western countries. Current best practice in the management of patients with PNES includes combined psychotherapy (e.g., cognitive behavioral therapy) and treatment of any psychiatric comorbidities [6]. In spite of that, access to appropriate psychotherapy is limited in many places in Iran (see the methods).…”

Psychological and demographic characteristics of 368 patients with dissociative seizures: data from the CODES cohort

“…The pre-randomisation measure of DS frequency was DS occurrence over the 4 weeks prior to psychiatric assessment (Robinson et al, 2017) with subjective severity of DS, and how Goldstein et al (2019). In addition, variables predicting which of the 698 participants did not attend psychiatry appointments have been reported by Stone et al (2020).…”