Article Figures & Data
- Table 1.
Pain outcome domains and instruments reported in included Cochrane summary of findings (SoF) tables.
SoF Tables, n = 57 Reviews* Outcome
Domain/SubdomainSoF Tables, n Outcome Instrument n Pain intensity 48** Unidimensional pain intensity scales: • VAS (0–10 cm or 0–100 mm) 28 • VAS (1–9) 11 • Verbal rating score (0–10) 1 • 10-point Likert scale 1 Multidimensional pain intensity scales: • WOMAC pain subscale score 1 • Hospital for Special Surgery pain subscale score 1 Dichotomous outcomes — instrument not reported • At least 50% improvement from baseline 2 • Patient Global Impression of Change [in pain] much or very much improved 2 • IMMPACT definition — any substantial pain benefit 1 • IMMPACT definition — at least moderate pain benefit 1 • Number of participants with resting pain 1 • Instrument not reported (only SMD reported) 10 (6) • Pain reported in SoF as an outcome, but not measured in included studies 6 Pain intensity/tender joints 2 Number of tender joints 1 Number of tender points 1 Multidomain outcomes including pain intensity 14 ACR50 response criteria 9 ASAS40 response criteria 1 ASAS partial remission response criteria 1 ASES Shoulder Score 1 Disease Activity Score (DAS28) 6 Hospital for Special Surgery knee score 1 Lequesne Index 1 QUALEFFO 1 Multidomain/dimension outcomes including pain intensity and pain interference 6 Neck Disability Index 2 DASH 3 Fibromyalgia Impact Questionnaire 1 Multidomain/dimension outcomes including pain interference 1 SF-12 1 Multidomain/dimension outcomes including pain intensity, pain frequency and pain interference 1 Osteoporosis quality of life 1 Pain not reported in SoF table 1 Not applicable ↵* More than 1 pain outcome can be reported per SoF table; 5 reviews had no included studies;
↵** 41 reported only “pain,” but we assumed pain intensity from the scale; outcome not measured in included studies. ACR 50: American College of Rheumatology 50% response criteria; ASES: American Shoulder and Elbow Surgeons Shoulder score; DASH: Disabilities of the Arm, Shoulder, and Hand; SF-12: Medical Outcome Study Short Form 12 Survey; VAS: visual analog scale; WOMAC: Western Ontario and McMaster Universities Arthritis Index: QUALEFFO: quality of life questionnaire in patients with vertebral fractures; SMD: standardized mean difference.
- Table 2.
Theme 1: Which concepts (or “domains”) of chronic pain should be included as “core” in Cochrane summary of findings tables?
Key Issues Raised by Respondents No. Respondents (denominator = 36) Pain intensity is an important outcome to present in SoF tables for chronic conditions 32 • A direct measure of pain, describes the pain experience; the first issue of communicating with HCP • There is clear and consistent evidence that improving pain results in improvements in fatigue depression, health-related quality of life and function, and work • Existing consensus on this by IMMPACT (PI measured on a 0–10 NRS) A 1-dimensional measure of PI alone does not capture the complexity of pain impact 10 • “This is to me more important: whether it [pain] stopped me from what I wanted to or needed to do rather than something that was just there. Rating the intensity of the pain might be impacted by whether it is preventing me from doing what I want/need to do” (quote from patient) • The best measure for a trial because it has the best sensitivity to change (i.e., intensity) doesn’t necessarily reflect a meaningful improvement in the patient experience Consideration of the phrasing and standardization of questions about PI with respect to: 7 • Time frame (e.g., current, last 24 hours, last month, change from previous time point) • Type of pain (e.g., average, least, worst) • Specification of activity (e.g., on movement, on walking, at rest) • Location (overall or global pain, pain targeted to a joint) • Recall bias concerns Difficulties in capturing and measuring the concept of PI 5 • It is framed by individual experience and tolerance • It is a qualitative construct that we are trying to quantify Importance of pain frequency • Is an important outcome to include in an SoF table 5 • “It depends” on condition, e.g., important to describe for recurrent/periodic/intermittent pain 11 Importance of pain interference with function • Is an important outcome to include in an SoF table 28 • How does it link or overlap with a measure of function alone? 2 • Oversimplification that improving pain improves function 1 Consideration of whether generic or disease-specific pain measures should be reported • Both 7 • Prefer generic (“pain is pain”) 4 • Prefer condition-specific 3 • Depends on the question and goal of the systematic review 5 • Generic helps to make comparisons across conditions, but a field may prefer to use condition-specific 4 Other pain-related domains for consideration: 15 • Pain duration, pain relief, pain behavior, pain quality, and the effect of pain on fatigue, activities of daily living, worker productivity, health-related quality of life, sexual activities, effect on partners/caregivers • Should consider both the etiology of the pain condition and the nature of the intervention Important to include patient perspective in the discussions 24 • Link with existing OMERACT pain working group and their discussions on pain domains and key issue: Is chronic non-cancer pain a disease in and of itself? • Consider OMERACT Filter 2.0 framework PI: pain intensity; HCP: healthcare practitioner; SoF: summary of findings; IMMPACT: Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials; NRS: numeric rating scale.
- Table 3.
Theme 2: Criteria for acceptable clinimetrics/psychometrics for core endpoints for inclusion in Cochrane summary of findings tables.
Key Issues Raised by Respondents No. Respondents (denominator = 36) Must establish congruent language about measurement properties 5 Terminology used in various groups is not consistent (e.g., meaning of “discrimination” differs in OMERACT and COSMIN contexts)
Need clear distinction between what to measure and how to measure 5 First, what is the most important construct to measure and then to discuss what is the best instrument to measure this construct
Need outcome instruments with acceptable clinimetric criteria before we can have a discussion on how best to express treatment response
Consideration of assumptions that instruments like NRS or VAS have underlying operational metrics 3 Concern about use of nonlinear scales to quantify a percentage improvement and the impact on MID/MCID calculations
Suggest attention to use of Rasch methods
Important to consider the instrument in terms of the intervention 2 Where you expect to see variation in the scale as a result of the intervention is the place on the scale that needs to be the most sensitive
Perhaps different scales might be needed depending on severity of pain and where we expect the intervention to act
COSMIN: COnsensus-based Standards for the selection of health Measurement INstruments; NRS: numeric rating scale; VAS: visual analog scale; MID/MCID: minimum important difference/minimal clinically important difference.
- Table 4.
Theme 3: Which “threshold of meaning” should be presented in the summary of findings table?
Key Issues Raised by Respondents No. Respondents (denominator = 36) There should be a presentation of the proportion of people reaching a certain threshold (e.g., proportion of patients achieving a 50% change from baseline). How to define the threshold? 26 • MCID 3 • “Collective ‘minimum important change’ can [not] be defended scientifically or logically” 1 • 50% is a very good pain reduction and recommended by IASP 5 • Pain responses tend to be bimodal — good relief or very little — an easy discriminating point is 50% 1 • What patients want is ≥ 50% pain intensity reduction 5 • 50% is a less realistic target 2 • Interested in empirical data re bimodal response 3 Show results for various thresholds 5 • E.g., 20%, 50%, 70% responders 3 • Report all percentage improvements in cumulative frequency distribution 5 • If concerned about statistical power; might find a statistically significant difference with mean change but not in a responder analysis 4 • Want to determine a reliable way to dichotomize continuous data 3 • Why limit to one way of presentation? Consider offering Web-based automatic calculation 1 Concern that a fixed proportion like 50% will bias against those with low/better scores at baseline 2 • Unless you have similar baselines, meaning is different There should be a presentation of proportion of people achieving a state, e.g., patient acceptable state, low or minimum state; a state of “no worse than mild pain” 17 • “Status/state” is much more important to a patient than “change” 8 • The important question for patients “Is your pain at a level now where you can function and do what you want/have to do without the pain being an issue?” 2 • It might be considered the ultimate goal of treatment as in reality NWTMP is what patients want — a manageable point vs not manageable point 3 • For many people in chronic conditions associated with pain, they will not be completely pain-free 3 • Keep magnitude and value separate, and focus on clear ways to present the data 1 Suggestions of thresholds for defining a “state” • Magnitude of change: below 4 on 0–10 NRS or less than 3 on 0–10 scale 2 • Based on patient response: Can ask patient at end of study if they are in an “acceptable state” 6 IASP: International Association for the Study of Pain; MCID: minimal clinically important difference; NWTMP: no worse than mild pain; NRS: numeric rating scale.
Key Issues Raised by Respondents No. Respondents (denominator = 36) Important for systematic reviewers
To reduce bias we need a systematic method to inform which pain outcome instrument to choose when more than 1 is reported in a trial
4 Different methods have been used to develop hierarchies for pain outcome instruments in OA Methods include expert opinion and responsiveness of pain outcome instruments in OA trials
What other criteria than responsiveness should be considered?
3 What is the patient perspective on this hierarchy? Could use concept mapping approach to get input from patients
2 Important to distinguish the hierarchy of constructs from hierarchy of instruments 2 OA: osteoarthritis.
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Supplementary data for this article are available online at jrheum.org.
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