To standardize outcome reporting in clinical trials of patients with nonspecific low back pain, an international multidisciplinary panel recommended physical functioning, pain intensity, and health-related quality of life (HRQoL) as core outcome domains. Given the lack of a consensus on measurement instruments for these 3 domains in patients with low back pain, this study aimed to generate such consensus. The measurement properties of 17 patient-reported outcome measures for physical functioning, 3 for pain intensity, and 5 for HRQoL were appraised in 3 systematic reviews following the COSMIN methodology. Researchers, clinicians, and patients (n = 207) were invited in a 2-round Delphi survey to generate consensus (≥67% agreement among participants) on which instruments to endorse. Response rates were 44% and 41%, respectively. In round 1, consensus was achieved on the Oswestry Disability Index version 2.1a for physical functioning (78% agreement) and the Numeric Rating Scale (NRS) for pain intensity (75% agreement). No consensus was achieved on any HRQoL instrument, although the Short Form 12 (SF12) approached the consensus threshold (64% agreement). In round 2, a consensus was reached on an NRS version with a 1-week recall period (96% agreement). Various participants requested 1 free-to-use instrument per domain. Considering all issues together, recommendations on core instruments were formulated: Oswestry Disability Index version 2.1a or 24-item Roland-Morris Disability Questionnaire for physical functioning, NRS for pain intensity, and SF12 or 10-item PROMIS Global Health form for HRQoL. Further studies need to fill the evidence gaps on the measurement properties of these and other instruments.

Inconsistent reporting of outcomes in clinical trials of patients with non-specific low back pain (NSLBP) hinders comparison of findings and the reliability of systematic reviews. A core outcome set (COS) can address this issue as it defines a minimum set of outcomes that should be reported in all clinical trials. In 1998, Deyo et al. recommended a standardized set of outcomes for LBP clinical research. The aim of this study was to update these recommendations by determining which outcome domains should be included in a COS for clinical trials in NSLBP. An International Steering Committee established the methodology to develop this COS. The OMERACT Filter 2.0 framework was used to draw a list of potential core domains that were presented in a Delphi study. Researchers, care providers and patients were invited to participate in three Delphi rounds and were asked to judge which domains were core. A priori criteria for consensus were established before each round and were analysed together with arguments provided by panellists on importance, overlap, aggregation and/or addition of potential core domains. The Steering Committee discussed the final results and made final decisions. A set of 280 experts was invited to participate in the Delphi; response rates in the three rounds were 52, 50 and 45 %. Of 41 potential core domains presented in the first round, 13 had sufficient support to be presented for rating in the third round. Overall consensus was reached for the inclusion of three domains in this COS: ‘physical functioning’, ‘pain intensity’ and ‘health-related quality of life’. Consensus on ‘physical functioning’ and ‘pain intensity’ was consistent across all stakeholders, ‘health-related quality of life’ was not supported by the patients, and all the other domains were not supported by two or more groups of stakeholders. Weighting all possible argumentations, the Steering Committee decided to include in the COS the three domains that reached overall consensus and the domain ‘number of deaths’. The following outcome domains were included in this updated COS: ‘physical functioning’, ‘pain intensity’, ‘health-related quality of life’ and ‘number of deaths’. The next step for the development of this COS will be to determine which measurement instruments best measure these domains.

Background: Physical functioning is a core outcome domain to be measured in nonspecific low back pain (NSLBP). A panel of experts recommended the Roland-Morris Disability Questionnaire (RMDQ) and Oswestry Disability Index (ODI) to measure this domain. The original 24-item RMDQ and ODI 2.1a are recommended by their developers.Purpose: The purpose of this study was to evaluate whether the 24-item RMDQ or the ODI 2.1a has better measurement properties than the other to measure physical functioning in adult patients with NSLBP.Data Sources: Bibliographic databases (MEDLINE, Embase, CINAHL, SportDiscus, PsycINFO, and Google Scholar), references of existing reviews, and citation tracking were the data sources.Study Selection: Two reviewers selected studies performing a head-to-head comparison of measurement properties (reliability, validity, and responsiveness) of the 2 questionnaires. The COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) checklist was used to assess the methodological quality of these studies.Data Extraction: The studies' characteristics and results were extracted by 2 reviewers. A meta-analysis was conducted when there was sufficient clinical and methodological homogeneity among studies.Data Synthesis: Nine articles were included, for a total of 11 studies assessing 5 measurement properties. All studies were classified as having poor or fair methodological quality. The ODI displayed better test-retest reliability and smaller measurement error, whereas the RMDQ presented better construct validity as a measure of physical functioning. There was conflicting evidence for both instruments regarding responsiveness and inconclusive evidence for internal consistency.Limitations: The results of this review are not generalizable to all available versions of these questionnaires or to patients with specific causes for their LBP.Conclusions: Based on existing head-to-head comparison studies, there are no strong reasons to prefer 1 of these 2 instruments to measure physical functioning in patients with NSLBP, but studies of higher quality are needed to confirm this conclusion. Foremost, content, structural, and cross-cultural validity of these questionnaires in patients with NSLBP should be assessed and compared.

Nonspecific low back pain is diagnosed by ruling out other causes, usually by means of history taking and physical examination; imaging is not routinely indicated. Patients with acute nonspecific low back pain should receive education about the condition and advice to remain active; most recover within weeks. Exercise therapy and behavioral therapy are recommended for chronic low back pain.