Discussion
disability, NRS, pain
Our results suggest that it is feasible to conduct a full-scale trial to compare the clinical and cost-effectiveness of the OPTimisE intervention compared with usual NHS physiotherapy care. We successfully recruited to target ahead of schedule, but the number of eligible patients identified was lower than predicted based upon site referral data at the planning stage of the project. This was offset by consent rates being far greater (71%) than the conservative feasibility target (25%) set In terms of fidelity, the OPTimisE intervention was delivered as intended to the majority of patients (89%). The pre-defined quantitative criteria for fidelity were binary (i.e. fidelity was achieved or not) but in two cases, fidelity was not achieved because physiotherapists only delivered five of the twelve advice/education topics instead of the six required to satisfy the fidelity criteria. The other remaining criteria, related to exercise prescription and provision of the counterforce brace, were all satisfied.Of the two patient identification methods, the screening of referrals at physiotherapy clinics was most successful, accounting for 49/50 patients recruited. The database screening at GP practices only generated three expressions of interest, with two of those already identified from referral screening, so this method is unlikely to be worthwhile within a future main trial.We found that questionnaire returns were low at six-week follow-up (59%). The follow-up questionnaires were sent at time points determined from the date of randomisation. Some patient participants told us in the interviews that they had not returned the questionnaire due to the fact that they had not yet started treatment or only recently started treatment at the time the questionnaire was sent, due to waiting times for initial physiotherapy appointments. Returns increased by 12-week follow-up to 65% but did not meet the feasibility threshold. We introduced a protocol amendment to allow telephone reminders and minimum data collection at this stage which, coupled with the pre-agreed £20 voucher incentive for six-month data return, resulted in an 81% response, surpassing the feasibility threshold.When we examined the responsiveness of the different PROMs included, the PRTEE measure of function and NRS for pain on gripping showed the highest correlation with patient perceived overall treatment effect. The PRTEE is the recommended primary outcome measure in the core outcome set for LET and the NRS for pain on gripping is recommended for interim use, pending psychometric evaluation (We piloted a method of grip-strength self-measurement using the Squegg device. Grip-strength data were provided in 77% of questionnaire returns, suggesting not all participants could/would use the device. Qualitative data suggested that some participants relied upon the assistance of family to use the device and one person was unable to connect it to their smartphone (Adherence to exercise remains a challenge in physiotherapy trials and is difficult to measure (Although the focus of this pilot and feasibility trial was not on between-group differences (and we did not conduct statistical tests to compare outcomes), the descriptive analysis of the data showed improvements in both groups in health outcomes over 6 months. In some outcomes, the trend was towards greater improvement in the usual care group than the intervention group for disability and perceived overall treatment effect, which was not expected. This may be explained by the usual care provided by the research-active sites involved in the trial being of higher quality than that provided by non-research-active centres more generally. Whilst a fully-powered future RCT would help ascertain whether the intervention is more clinically- or cost-effective than usual care, a future trial using the same intervention approach is unlikely to be desirable given the results of this pilot. A recent systematic review and meta-analysis of LET trials including placebo or wait-and-see controls suggested that following enrolment in a clinical trial, patients experience improvements over time without any active treatment, regardless of symptom duration prior to enrolment (The strengths of this study are that we were able to pilot different methods of participant identification, data collection and outcomes questionnaires, with clear quantitative and qualitative findings that allow us to refine the method of a future main trial. We included patient and public experience in our intervention and trial design. The design was limited by the lack of translation services, potentially resulting in fewer underserved communities being represented, but this could be addressed in the main trial design.