Clinimetrics: A core outcome measurement set for low back pain

摘要

A core outcome set (COS) defines: the core outcome domains, andthe core outcome measurement instruments.1 It is a minimum agreedset of outcomes to be measured in all clinical trials for a given healthcondition to facilitate comparability of trials’ results and metaanalyses, and to avoid selective outcome reporting bias.2 A COS forall clinical trials in adult patients with non-specific low back pain(LBP) was developed by an international and multidisciplinary groupof researchers, clinicians and patient representatives.3,4 Consensus oncore outcome domains4 and measurement instruments3 was achieved through two multi-round Delphi surveys. The followingpatient-reported instruments are recommended: Oswestry DisabilityIndex 2.1a (ODI 2.1a) and 24-item Roland Morris Disability Questionnaire (RMDQ-24) for physical functioning; 11-point NumericRating Scale (NRS) for pain intensity; Short Form 12 (SF-12) or10-item PROMIS Global Health (PROMIS-GH-10) for HRQoL.3 Thefourth core outcome domain (ie, number of deaths) can be covered bya simple statement reporting if any death occurred.4ODI 2.1a includes 10 items referring to different activities of dailyliving and other domains (eg, pain intensity, social life) to be scoredon a 5-point Likert scale; the total percentage score ranges from 0 to100. RMDQ-24 includes items referring to different physical functionsinfluenced by LBP that patients can check if relevant to them on that day; the total score ranges from 0 to 24. NRS is a horizontal lineranging from 0 (‘no pain’) to 10 (‘worst imaginable pain’) and askinga patient to rate his/her average LBP intensity over the past week. SF-12 includes 12 items referring to eight different health domains witha different number response options, and providing physicalcomponent summary (PCS) and mental component summary (MCS)scores. PROMIS-GH-10 also measures eight different health domains,nine of which with 1 to 5 response options and one with a 0 to 10NRS; these items are used to compute PCS and MCS that, like for SF-12, are expressed as T-scores, with higher scores indicating betterhealth. ODI 2.1a and SF-12 are instruments with a fee, whereasRMDQ-24, NRS and PROMIS-GH-10 can be used entirely free ofcharge.The validity of a core outcome set is ensured by different components, such as clearly defining its scope (in terms of setting, condition, population and interventions), involving all relevantstakeholders in the consensus process (most importantly: patients),and defining a-priori criteria for consensus and for including/dropping/adding outcomes in the consensus process.5 All these aspectswere covered in the consensus process on core outcomes for LBP.4Meanwhile, the judgement of validity of a core outcome measurement set lacks consensus-based criteria.