Pain phenotyping and investigation of outcomes in physical therapy: An exploratory study in patients with low back pain

Quantitative sensory testing and exercise-induced hypoalgesia protocols in low back pain: A scoping review

A significant driver of pain in individuals with low back pain (LBP) is alterations to endogenous pain modulation (EPM). EPM can be measured using quantitative sensory testing (QST), however; there are inconsistencies in the way QST has been implemented across the low back pain literature. The objective of this scoping review was to summarize protocols used to assess EPM using QST (pain pressure threshold (PPT), temporal summation (TS), conditioned pain modulation (CPM)) or exercise-induced hypoalgesia (EIH) in LBP. Databases Medline, Embase, CINAHL and AMED were searched on June 15, 2023, for articles that used QST or EIH protocols in LBP populations. Data was extracted on participants, study design, setting and details on QST and EIH protocols. Of the 221 studies included in the review, 196 used PPT, 62 used TS and 60 used CPM; only 5 studies investigated EIH. For all QST, there was high variability in the type of equipment, timing, trials, and testing location with many studies not reporting this information. There were 4 testing modalities used for TS, and 7 different test stimuli, and 3 different conditioning stimuli used across the studies for CPM. For CPM and EIH, PPT was the most common testing modality. There were 4 types of exercises used across the 5 EIH studies. This scoping review provides a summary of QST and EIH protocols in LBP that may be used as a guide for assessment in future studies. These results demonstrate a need for the development of standardized protocols and reporting guidelines. PERSPECTIVE: This article presents a summary of measures used to assess EPM in LBP. The results show the wide variability of protocols used in the literature. Future research should focus on creating standardized protocols, reporting guidelines and providing more guidance for researchers in selecting appropriate tests for their research questions.

General and Pain-Associated Psychological Distress Phenotypes Among Patients With Low Back Pain in the Military Health System

OBJECTIVE

The primary objective was to describe rates of general and pain-related psychological distress for individuals with low back pain (LBP) in the Military Health System (MHS). We identified common phenotypes defined by rates of general and pain-related psychological distress and compared phenotypes on their level of pain interference, physical function, anxiety, and depression.

METHODS

We created a cohort from two completed trials assessing nonpharmacological treatment for LBP in the MHS (n = 510 total). The Optimal Screening for Prediction of Referral and Outcome Yellow Flag assessment tool identified the presence of 11 different yellow flags. Latent class analysis (LCA) used yellow flag indicators to identify common psychological phenotypes. We then compared Patient-Reported Outcomes Measurement Information Systems measures of pain interference, physical function, sleep disturbance, depression, and anxiety across phenotypes.

RESULTS

LCA identified five phenotypes (percentage of the sample): low distress (32%), high distress (27%), poor pain coping and low self-efficacy (18%), low self-efficacy and acceptance (14%), and poor pain coping (10%). Highly distressed phenotypes reported higher levels of pain interference, sleep disturbance, depression, and anxiety than those with other phenotypes, whereas the low distress phenotype had significantly lower pain interference and higher physical function scores than those characterized by all other phenotypes.

CONCLUSION

These phenotypes provide opportunities for clinicians and researchers to develop novel LBP treatment pathways tailored to patients with different profiles of psychological distress. Future work is needed to validate their predictive capabilities for clinical outcomes.

Patient-reported outcome measures in physical therapy practice for neck pain: an overview of reviews

BACKGROUND

Understanding which patient-reported outcome measures are being collected and utilized in clinical practice and research for patients with neck pain will help to inform recommendations for a core set of measures that provide value to patients and clinicians during diagnosis, clinical decision-making, goal setting and evaluation of responsiveness to treatment. Therefore, the aim of this study was to conduct a review of systematic reviews using a qualitative synthesis on the use of patient-reported outcome measures (PROMs) for patients presenting with neck pain to physical therapy.

METHODS

An electronic search of systematic reviews and guideline publications was performed using MEDLINE (OVID), Embase (Elsevier), CINAHL Complete (EBSCOhost), and Web of Science (Clarivate) databases to identify reviews that evaluated physical therapy interventions or interventions commonly performed by a physical therapist for individuals with neck pain and included at least one patient-reported outcome measure. The frequency and variability in which the outcome measures were reported among the studies in the review and the constructs for which they measured were evaluated. The evaluation of a core set of outcome measures was assessed. Risk of bias and quality assessment was performed using A Measurement Tool to Assess systematic Reviews 2.

RESULTS

Of the initial 7,003 articles, a total of 37 studies were included in the final review. Thirty-one PROMs were represented within the 37 reviews with eleven patient-reported outcome measures in three or more reviews. The eleven PROMs assessed the constructs of disability, pain intensity, psychosocial factors and quality of life. The greatest variability was found amongst individual measures assessing psychosocial factors. Assessment of psychosocial factors was the least represented construct in the included studies. Overall, the most frequently utilized patient reported outcome measures were the Neck Disability Index, Visual Analog Scale, and Numeric Pain Rating Scale. The most frequently used measures evaluating the constructs of disability, pain intensity, quality of life and psychosocial functioning included the Neck Disability Index, Visual Analog Scale, Short-Form-36 health survey and Fear Avoidance Belief Questionnaire respectively. Overall risk of bias and quality assessment confidence levels ranged from critically low (2 studies), low (12 studies), moderate (8 studies), and high (15 studies).

CONCLUSION

This study identified a core set of patient-reported outcome measures that represented the constructs of disability, pain intensity and quality of life. This review recommends the collection and use of the Neck Disability Index and the Numeric Pain Rating Scale or Visual Analog Scale. Recommendation for a QoL measure needs to be considered in the context of available resources and administrative burden. Further research is needed to confidently recommend a QoL and psychosocial measure for patients presenting with neck pain. Other measures that were not included in this review but should be further evaluated for patients with neck pain are the Patient Reported Outcomes Measurement Information System (PROMIS) Physical function, PROMIS Pain Interference and the Optimal Screening for Prediction of Referral and Outcome Yellow Flag (OSPRO-YF) tool.