Mixed-methods development of a new patient-reported outcome instrument for chronic low back pain: part 1-the Patient Assessment for Low Back Pain - Symptoms (PAL-S)

Rasch analysis of the Back Pain Attitudes Questionnaire (Back-PAQ)

CONTEXT

As psychosocial factors have been recognised as significant predictors of the recovery trajectory from chronic back pain, the 34-item Back Pain Attitudes Questionnaire (Back-PAQ) was developed based on themes obtained from patient interviews, but previous psychometric analyses with a general population sample revealed uncertainty around the factor structure of the instrument.

OBJECTIVES

To provide more detailed information about the psychometric properties of the Back-PAQ when used with participants from the general population and also to test the internal validity of the tool for use with General Practitioners (GPs).

METHODS

After applying partial-credit Rasch analysis with a sample of participants from the general population (n = 600), a replication analysis was conducted with a sample of GPs (n = 184). This approach permitted examination of sample-specific personal factors for differential item functioning. Subtests were used to differentiate between local dependency due to underlying dimensionality from local dependency due to method effects.

RESULTS

A unidimensional fit to the Rasch model was achieved after 14 misfitting items had been deleted. The final 20-item solution also fit with a sample of 184 GPs. In both cases, the Back-PAQ-20 demonstrated good reliability (PSI ≥ 0.80), with no evidence of differential item functioning by personal factors.

CONCLUSION

The ordinal-to-interval conversion algorithms presented here further enhance the precision of the scale and permit analysis of Back-PAQ-20 scores using parametric statistics. The present study provided evidence for valid and reliable assessment of the back pain recovery beliefs of both users as well as providers of health services.IMPLICATIONS FOR REHABILITATIONPsychosocial factors have been recognised as significant predictors of the recovery trajectory from chronic back pain.The 34-item Back Pain Attitudes Questionnaire (Back-PAQ) was developed based on themes obtained from patient interviews, but previous psychometric analyses with a general population sample revealed uncertainty around the factor structure of the instrument.The 20-item version of the Back Pain Attitudes Questionnaire (Back-PAQ) is shown here to have strong psychometric properties for administration with users and providers of health services.

Validation of the Questionnaire for Symptom Assessment in Pain disorders for Back pain patients (Q-SAP)

BACKGROUND

Previous studies have shown that not only pain intensity but also impairment of quality of life and functionality are important parameters for the evaluation of treatment of chronic low back pain patients. The aim of the study was to validate a specific self-questionnaire for symptom assessment and their influence on quality of life and functionality of chronic low back pain patients (Questionnaire for Symptom Assessment in Pain disorders for back pain patients, Q-SAP).

METHODS

The self-questionnaire consists of two parts (for back and if applicable leg symptoms) and was tested in 152 chronic low back pain patients with and without radiculopathy. Test-retest reliability, exploratory factor analysis, convergent validity, criterion-related validity and the sensitivity to detect patient reported changes were investigated.

RESULTS

The questionnaire showed a good to excellent test-retest reliability. In the factor analysis nociceptive and neuropathic pain components could be separated and the highest convergent validities were shown for the painDETECT, EQ-5D-3L and the FFbH-R. The criterion-related validity showed concordance of QST and the Q-SAP Back for warmth induced pain and numbness. Regarding the sensitivity to patient-reported changes, a moderate correlation was found for both parts of the questionnaire.

CONCLUSIONS

The Q-SAP was tested as a useful, valid and reliable tool. This new questionnaire records classical nociceptive and neuropathic pain symptoms of chronic low back pain patients depending on their local distribution. Furthermore, the questionnaire records the intensity of these symptoms and their influence on quality of life and functionality and can be used for the evaluation of treatment.

SIGNIFICANCE

The Q-SAP Back/Leg is a new self-questionnaire for CLBP patients with or without radiating leg pain that precisely assesses neuropathic and nociceptive symptoms. In contrast to other questionnaires, the Q-SAP Back/Leg evaluates not only symptom intensities but also their impact on the patient's quality of life and functionality. Furthermore, this questionnaire requests the symptoms depending on their anatomical distribution.

Pain assessment for chronic lower back pain: performance of the PAL-S and PAL-I patient-reported measures for symptoms and impacts

Objective: The Patient Assessment for Low Back Pain-Symptoms (PAL-S) and the Patient Assessment for Low Back Pain-Impacts (PAL-I) were developed to incorporate patient perspective of treatment benefit in chronic low back pain (cLBP) trials. This study documents psychometric measurement properties of the PAL-S and PAL-I.Methods: In this multicenter, observational study, eligible participants clinically diagnosed with cLBP provided sociodemographic information and completed PAL measures and other patient-reported outcome measures of pain and/or disability. Confirmatory factor analyses (CFA), construct validity, and reliability were assessed.Results: The 104 participants were 61% female, 89% white, and mean age of 55 years; mean cLBP duration was 11.4 (range 0-47) years. Using painDETECT scores, 36.5% reported small likelihood of neuropathic pain, 30.8% reported unclear likelihood, and 32.7% reported definite likelihood. Persistent pain with pain attacks was reported by 38.5% of participants. CFA confirmed single components with adequate fit indices. Cronbach's alpha was 0.83 (PAL-S) and 0.87 (PAL-I), indicating reliable scales. Intraclass correlation coefficients (test-retest reproducibility, n = 44) were 0.81 (PAL-S) and 0.85 (PAL-I). PAL-S score correlation was 0.49 with Roland-Morris Disability Questionnaire (RMDQ) and 0.77 with Neuropathic Pain Symptom Inventory (NPSI). PAL-I correlated at 0.73 with RMDQ and -0.60 with Medical Outcomes Study (MOS)-36 Bodily Pain. Both measures significantly differentiated between pain intensity levels (based on numeric response scale) and painDETECT groups.Conclusion: The PAL-S and PAL-I generated highly reliable scores with substantial evidence of construct validity. Routine use of these measures in treatment trials will enhance comparability of LBP-related symptom and impact results, including patient perspective of treatment benefit.

A Longitudinal Analysis of Total Pain Scores for a Panel of Patients Treated by Pain Clinics

Background:

There is a critical necessity to identify psychometric properties of the total pain score as a measurement of pain management effectiveness in the clinic.

Purpose:

In this article, we perform the analysis of the global pain scores from a panel of patients treated by 10 pain management physicians in a single group practice.

Basic Procedures:

The pain measurement consists of 4 pain subscales, namely physical pain, emotions, clinical outcome, and activities. A panel of 130 patients with 4 pain measurements is available to perform longitudinal analysis of the total pain scores. The analysis includes the following: (1) confirmatory factor analysis of the global pain scores with 4 related dimensions, (2) the stability of the pain scores between 2 clinical visits, (3) the change trajectories of pain scores in 4 waves of the pain measurement, and (4) the detection of physician variability in patients’ treatment outcomes measured by the reduction of total pain scores.

Main Findings:

The global pain scores were relatively stable between time 1 and time 2 clinical visits. The analysis indicated that there was a decrease in pain with longitudinal advancement in treatment. It also indicated that there was no significant change in this improvement with respect to difference in physicians involved in providing treatment.

Principal Conclusion:

While the results indicated a decrease in pain with an alleviation in treatment provided to the patient, the article delineates a well-thought scientific approach to the targeted problem.

Are painDETECT scores in musculoskeletal disorders associated with duration of daily pain and time elapsed since current pain onset?

Objectives:

We aimed to compare painDETECT scores in outpatients seen in a rheumatology department over a 1-month period and search for correlations between painDETECT scores and the estimated duration of daily pain and time elapsed since the onset of current pain.

Patients and Methods:

A total of 529 of 738 outpatients agreed to complete a set of questionnaires, including painDETECT.

Results:

The mean painDETECT score was 14.14 ± 7.59, and 31% of the patients had painDETECT scores of >18. Fibromyalgia ranked first (21.2 ± 6.0), followed by osteoarthritis of the lower limbs (17.8 ± 8.2), back pain and radiculopathies (16.1 ± 6.8), osteoarthritis of the upper limbs (15.7 ± 8.1), spondylarthrosis (15.1 ± 7.2), entrapment neuropathies (14.1 ± 2.4), rheumatoid arthritis (13.8 ± 7.1), miscellaneous conditions (13.8 ± 8.2), tendinitis (13.4 ± 7.9), connectivitis (11.5 ± 6.7), and osteoporosis (8.5 ± 6.9). The duration of daily pain was much longer in patients with painDETECT scores of >18 (12.41 ± 8.45 vs 6.53 ± 7.45 hours) (t = 0.0000), but very similar painDETECT scores were observed for patients suffering from pain for less than 1 week (13.7 ± 8.2; 38% > 18), for 1 month (14.5 ± 8.2; 25% > 18), several months (12.7 ± 7.3; 23% > 18), 1 year (13.8 ± 7.7; 29% > 18), or several years (14.7 ± 7.4; 33% > 18).

Conclusion:

PainDETECT scores differed little depending on the musculoskeletal condition, strongly correlated with the duration of daily pain, and appeared to be as high in patients with recent pain as in those suffering for years.

Producing a preference-based quality of life measure for people with Duchenne muscular dystrophy: a mixed-methods study protocol

INTRODUCTION

Preference-based measures (PBMs) of health-related quality of life (HRQoL) are used to generate quality-adjusted life years, which are necessary for cost-effectiveness evaluations of health interventions via cost-utility analysis. These measures of health can be generic (ie, pandiagnostic) or condition specific. No condition-specific PBM of HRQoL in Duchenne muscular dystrophy (DMD) exists, yet there are concerns that standard generic measures lack the specificity to assess aspects of HRQoL that are especially important to people with DMD. This study has been designed to produce a condition-specific PBM of HRQoL in DMD.

METHODS AND ANALYSIS

This mixed-methods study proceeds through three stages. In the first stage (concept elicitation), semistructured interviews will be conducted with boys and men diagnosed with DMD, and analysed with framework to produce a draft health state descriptive system for HRQoL in DMD. In the second stage (refining the descriptive system), patients, clinicians and primary caregivers of people with DMD will assess the face validity of the descriptive system. This will be followed by a quantitative survey on a larger sample of patients, which will be analysed with psychometric analyses to produce a refined descriptive system. In the third stage (valuation and econometric modelling), an online discrete choice experiment with duration will be administered to a general public sample to generate utility values for the new measure.

ETHICS AND DISSEMINATION

This study has received ethical approval from the National Health Service (REC reference: 18/SW/0055). The primary output of this research will be a condition-specific PBM (or 'bolt-on' to an existing generic PBM) in people with DMD and an associated value set. Results will be disseminated through international conferences and open-access journals.

Lessons from Outside and Within: Exploring Advancements in Methodology for Naturopathic Medicine Clinical Research

Introduction: Naturopathy is a mixture of both traditional and complementary medicine. It incorporates a broad set of health care practices that may or may not be traditional to that country or conventional medicine and are not fully integrated into the dominant health care system. Research required to evaluate or substantiate naturopathic medicine may not fall under the testing of randomized clinical trials, which opens up discussions on what is the best practice for research in naturopathic medicine.

Discussion: Not only do advances in health research methodology offer important opportunities to progress naturopathic research, there are also areas where the unique characteristics of naturopathic philosophy and practice can impact other areas of health research. Some of the new advances in health research methodology involve whole-system research, pragmatic trials, template for intervention description and replication protocols for complex interventions, patient-centered care models, and the pragmatic-explanatory continuum indicator summary tool for designing pragmatic trials. Discussion and critique of these health-related methodologies shows that these research methods are more suited for the philosophy and treatment options that naturopathy is based on.

Conclusions: Successful implementation of naturopathic research methodologies, and translation and dissemination of research will require a substantial paradigm shift in which naturopathic practitioners adopt a greater level of responsibility for developing an evidence base for naturopathic medicine.

Mixed-methods development of a new patient-reported outcome instrument for chronic low back pain: part 2-The Patient Assessment for Low Back Pain-Impacts (PAL-I)

We describe qualitative and quantitative development and preliminary validation of the Patient Assessment for Low Back Pain-Impacts (PAL-I), a patient-reported outcome measure for use in chronic low back pain (cLBP) clinical trials. Concept elicitation and cognitive interviews (qualitative methods) were used to identify and refine symptom concepts. Classical test theory and Rasch measurement theory (quantitative methods) were used to evaluate item-level and scale-level performance of the PAL-I using an iterative approach between qualitative and quantitative methods. Patients with cLBP participated in concept elicitation interviews (N = 43), cognitive interviews (N = 38), and assessment of paper-to-electronic format equivalence (N = 8). A web-based sample of self-reported patients with cLBP participated in quantitative studies to evaluate preliminary (N = 598) and revised (n = 401) drafts and patients with physician-diagnosed cLBP (N = 45) participated in preliminary validation of the PAL-I. The instrument contained 9 items describing cLBP impacts (walking, sitting, standing, lifting, sleep, social activities, travelling, climbing, and body movements). Item-level performance, scale structure, and scoring seemed to be appropriate. One-week test-retest reproducibility was acceptable (intraclass correlation coefficient 0.88 [95% confidence interval, 0.78-0.94]). Convergent validity was demonstrated with PAL-I total score and Roland-Morris Disability Questionnaire (Pearson correlation 0.82), MOS-36 Physical Functioning (-0.71), and MOS-36 Bodily Pain (-0.71). Individual item scores and total score discriminated between numeric rating scale tertile groups and painDETECT categories. Interpretation of paper and electronic administration modes was equivalent. The PAL-I demonstrated content validity and is potentially useful to assess treatment benefit in clinical trials of cLBP therapies.