Interdisciplinary multimodal pain therapy (IMPT) is a biopsychosocial treatment approach for patients with chronic pain that comprises at least psychological and physiotherapeutic interventions. Core outcome sets (COSs) are currently developed in different medical fields to standardize and improve the selection of outcome domains, and measurement instruments in clinical trials, to make trial results meaningful, to pool trial results, and to allow indirect comparison between interventions. The objective of this study was to develop a COS of patient-relevant outcome domains for chronic pain in IMPT clinical trials. An international, multiprofessional panel (patient representatives [n = 5], physicians specialized in pain medicine [n = 5], physiotherapists [n = 5], clinical psychologists [n = 5], and methodological researchers [n = 5]) was recruited for a 3-stage consensus study, which consisted of a mixed-method approach comprising an exploratory systematic review, a preparing online survey to identify important outcome domains, a face-to-face consensus meeting to agree on COS domains, and a second online survey (Delphi) establishing agreement on definitions for the domains included. The panel agreed on the following 8 domains to be included into the COS for IMPT: pain intensity, pain frequency, physical activity, emotional wellbeing, satisfaction with social roles and activities, productivity (paid and unpaid, at home and at work, inclusive presentism and absenteeism), health-related quality of life, and patient's perception of treatment goal achievement. The complexity of chronic pain in a biopsychosocial context is reflected in the current recommendation and includes physical, mental, and social outcomes. In a subsequent step, measurement instruments will be identified via systematic reviews.

Introduction: Multimodal pain therapy (MPT) has been established accounting for biopsychosocial consideration in diagnostic and therapy. MPT seems to be effective, but comparability of studies is limited due to diversity of study designs and outcome measurements. The presented study aims to develop a core outcome set consisting of a minimum of outcome measures deemed necessary for medical and therapeutic decision-making, which must be measured in all clinical trials and non-randomised intervention studies. Methods and analysis: The study consists of several parts. First, the development and recommendation of preliminary core outcome domains will be based on results of a systematic review and structured online surveys. Participants of the expert panel are representatives of methodological, medical, physiotherapeutic, psychotherapeutic profession and patients suffering from chronic pain (n=25). Subsequently, candidate instruments to measure preliminary core outcome domains will be recommended by these experts. Therefore, systematic reviews on measurement properties of preliminary outcome measures will be conducted and finalised in a consensus meeting. Consented instruments and lacking psychometric properties of relevant instruments will be addressed and validated in the following part, a prospective multicentre study in multimodal pain centres on approximately 300 patients with chronic pain. Based on all previous results, a core outcome set for MPT measured in effectiveness studies and daily recordkeeping will be finalised by consensus. Statistical analyses will be performed according to methodological standards (COSMIN). Ethics and dissemination: The methods and procedure of the study are developed in compliance with the ethical principles of the Helsinki Declaration and Good Epidemiologic Practice. Recruitment of study participants will require approval of the study by the responsible ethics committee and signed informed consent from each participant. Pseudonymised data will be used for statistical analysis.

Zusammenfassung: Die Versorgung von Patienten mit Schmerzen und Chronifizierungsrisiko ist nach wie vor gekennzeichnet durch Über‑, Fehl- und Unterversorgung. Das Projekt PAIN2020 (Innovationsfonds 01NVF17049) hat zum Ziel, durch die Einführung eines frühzeitigen, auf Schmerz spezialisierten interdisziplinären diagnostischen Ansatzes die ambulante Versorgung von Patienten im Hinblick auf Schmerzen und das Funktionsniveau zu verbessern. Im Rahmen einer randomisierten kontrollierten Studie werden bundesweit in 31 Einrichtungen der Regelversorgung (schmerzspezialisiertes Angebot) Patienten mit Risikofaktoren bei bestehenden Schmerzen einer frühen Schmerzdiagnostik zugeführt. Die Interventionsbedingung besteht dabei in einem interdisziplinären multimodalen Assessment mit den beteiligten Disziplinen Schmerzmedizin, Physiotherapie und Psychologie. Die Kontrollbedingung umfasst einen einmaligen Termin bei einem Schmerztherapeuten der Qualitätssicherungsvereinbarung Schmerzmedizin bzw. mit Zusatzbezeichnung spezielle Schmerztherapie. Patienten und Vorbehandler erhalten entsprechend der Befunde detaillierte Empfehlungen für eine weitere bedarfsgerechte Behandlung. Es sind 2 Evaluationsansätze geplant. Für den ersten beträgt die zu erreichende Nettofallzahl 3840 Patienten, deren klinische Daten (Deutscher Schmerzfragebogen, zusätzliche Skalen) längsschnittlich erhoben (Einschluss, 3 und 6 Monate nach Diagnostik) und auf Grundlage eines Mehr-Ebenen-Modells ausgewertet werden. Im Rahmen eines 2. Ansatzes werden diese klinischen Daten einerseits um Sekundärdaten der BARMER ergänzt sowie die Patienten des ersten Evaluationsansatzes mit BARMER-Versicherten gematcht, die an dem Projekt nicht teilgenommen haben. Die Auswertung übernimmt ein externes Evaluationsinstitut. Das Projekt startete im April 2018.

Core Outcome Sets (COSs) are a set of domains and measurement instruments recommended for application in any clinical trial to ensure comparable outcome assessment (both domains and instruments). COSs are not exclusively recommended for clinical trials, but also for daily record keeping in routine care. There are several COS recommendations considering clinical trials as well as multidimensional assessment tools to support daily record keeping in low back pain. In this article, relevant initiatives will be described, and implications for research in COS development in chronic pain and back pain will be discussed.