Introduction Complex Regional Pain Syndrome (CRPS) is a persistent pain condition with low prevalence. Multi-centre collaborative research is needed to attain sufficient sample sizes for meaningful studies. This international observational study: (1) tested the feasibility and acceptability of collecting outcome data using an agreed core measurement set (2) tested and refined an electronic data management system to collect and manage the data. Methods Adults with CRPS, meeting the Budapest diagnostic clinical criteria, were recruited to the study from 7 international research centres. After informed consent, a questionnaire comprising the core set outcome measures was completed: on paper at baseline (T1), and at 3 or 6 months (T2) using a paper or e-version. Participants and clinicians provided feedback on the data collection process. Clinicians completed the CRPS severity score at T1 and optionally, at T2. Ethical approval was obtained at each international centre. Results Ninety-eight adults were recruited (female n=66; mean age 46.6 years, range 19-89), of whom 32% chose to receive the T2 questionnaire in an electronic format. Fifty-five participants completed both T1 and T2. Eighteen participants and nine clinicians provided feedback on their data collection experience. Conclusion This study confirmed the questionnaire core outcome data are feasible and practicable to collect in clinical practice. The electronic data management system provided a robust means of collecting and managing the data across an international population. The findings have informed the final data collection tools and processes which will comprise the first international, clinical research registry and data bank for CRPS.

ABSTRACT Complex regional pain syndrome (CRPS) clinical trials have historically captured a diverse range of outcomes. A minimum set of CRPS patient-reported outcomes has been agreed for inclusion in a future CRPS international clinical research registry and data bank. This study aimed to identify a complementary set of core clinical outcomes. Clinicians and researchers from the international CRPS community informed the content of a 2-round electronic Delphi study. Participation was invited from members of the International Association for the Study of Pain CRPS Special Interest Group and the International Research Consortium for CRPS. In round 1, participants rated the relevance of 59 clinical outcomes in relation to the question "What is the clinical presentation and course of CRPS, and what factors influence it?" (1 = not relevant and 9 = highly relevant). In round 2, participants rerated each outcome in the light of the round 1 median scores. The criterion for consensus was median score ≥7, agreed by 75% of respondents. The core study team considered the feasibility of data collection of each identified outcome in agreeing final selections. Sixty respondents completed both survey rounds, with responses broadly consistent across professions. Nine outcomes met the consensus criterion. Final outcomes recommended for inclusion in the core clinical set were record of medications, presence of posttraumatic stress disorder, extent of allodynia, and skin temperature difference between limbs. Study findings provide robust recommendations for core clinical outcome data fields in the future CPRS international clinical research registry. Alongside patient-reported outcomes, these data will enable a better understanding of CRPS.

Objectives This international, multicentre study will inform the final data collection tools and processes which will comprise the first international, clinical research registry for complex regional pain syndrome (CRPS). This study will: (a) test the feasibility and acceptability of collecting outcome measurement data using a patient reported, questionnaire core measurement set (COMPACT [Core Outcome Measurement set for complex regional PAin syndrome Clinical sTudies]); and (b) test and refine an electronic data management system to collect and manage the data. Methods A maximum of 240 adults, meeting the Budapest diagnostic clinical criteria for CRPS type I or II, will be recruited across eight countries. The COMPACT questionnaire will be completed on two occasions: at baseline (T1) and 6 months later (T2). At T2, participants will choose to complete COMPACT using a paper or electronic version. Participants will be asked to feed back on their experience of completing COMPACT via a questionnaire. A separate questionnaire will ask clinicians to feed back their experience of data collection. Analysis The study is not aiming to derive statistically significant data but to ascertain the practicalities of collecting data, using the COMPACT questionnaire set, across a range of different cultures and populations. At the end of the study, a single workshop will be convened to review the findings and agree the final documents and processes for the international registry.

Background & objectives: Complex Regional Pain Syndrome (CRPS) is a severe chronic pain condition characterised by a wide range of sensory, motor and autonomic abnormalities, usually in a single limb. CRPS clinical studies have historically used a diverse range of outcome measures to capture the multi-dimensional nature of the condition, however this has hindered the meaningful comparison and pooling of data[1]. In response, the COMPACT consortium published recommendations for a minimum core set of patient-reported outcome measures[2] and has established an international registry to collect and manage these data. The current study aims to extend the work of the COMPACT consortium by using an electronic Delphi process to develop a complementary set of clinical outcome measures. Method: From a systematic literature review, and subsequent workshop with clinicians and academics, a list of clinical outcomes has been developed for potential inclusion in a core clinical outcome set. In round 1 of the e-Delphi study, CRPS clinicians and researchers internationally will be asked to rate each outcome in relation to its relevance to the question: “What is the clinical presentation and course of CRPS, and what factors influence it?” Free text comments will also be elicited. In round 2, respondents will be presented with their individual ratings, the median group ratings for each item, and anonymised free-text comments. Respondents will be asked to re-rate in the light of this information. Outcomes with a final group median score of ≥ 7, as agreed by 75% of the study group[3], will be considered the draft ‘core clinical outcome measurement set’. This will be discussed by members of the COMPACT consortium to determine the final core set. Conclusions Findings from the study will inform the final combined set of patient-reported and clinical outcome measures which will be advocated for use in all CRPS clinical trials. References 1. Grieve, S., Jones, L., Walsh, N., and McCabe, C., 2016. What outcome measures are commonly used for Complex Regional Pain Syndrome clinical trials? A systematic review of the literature. European Journal of Pain, 20(3), pp.331-340. 2. Grieve, S., Perez, R.S., Birklein, F., Brunner, F., Bruehl, S., Harden, N., Packham, T., Gobeil, F., Haigh, R., Holly, J. and Terkelsen, A., 2017. Recommendations for a first Core Outcome Measurement set for complex regional PAin syndrome Clinical sTudies (COMPACT). Pain, 158(6), p.1083. 3. McMillan, S.S., King, M., Tully, M.P., 2016. How to use the Nominal Group and Delphi techniques. International Journal of Clinical Pharmacy, 38(3), pp.655–662.