Natural Language Processing of Referral Letters for Machine Learning-Based Triaging of Patients With Low Back Pain to the Most Appropriate Intervention: Retrospective Study.

BACKGROUND: Decision support systems (DSSs) for suggesting optimal treatments for individual patients with low back pain (LBP) are currently insufficiently accurate for clinical application. Most of the input provided to train these systems is based on patient-reported outcome measures. However, with the appearance of electronic health records (EHRs), additional qualitative data on reasons for referrals and patients' goals become available for DSSs. Currently, no decision support tools cover a wide range of biopsychosocial factors, including referral letter information to help clinicians triage patients to the optimal LBP treatment. OBJECTIVE: The objective of this study was to investigate the added value of including qualitative data from EHRs and referral letters to the accuracy of a quantitative DSS for patients with LBP. METHODS: A retrospective study was conducted in a clinical cohort of Dutch patients with LBP. Patients filled out a baseline questionnaire about demographics, pain, disability, work status, quality of life, medication, psychosocial functioning, comorbidity, history, and duration of pain. Referral reasons and patient requests for help (patient goals) were extracted via natural language processing (NLP) and enriched in the data set. For decision support, these data were considered independent factors for triage to neurosurgery, anesthesiology, rehabilitation, or minimal intervention. Support vector machine, k-nearest neighbor, and multilayer perceptron models were trained for 2 conditions: with and without consideration of the referral letter content. The models' accuracies were evaluated via F1-scores, and confusion matrices were used to predict the treatment path (out of 4 paths) with and without additional referral parameters. RESULTS: Data from 1608 patients were evaluated. The evaluation indicated that 2 referral reasons from the referral letters (for anesthesiology and rehabilitation intervention) increased the F1-score accuracy by up to 19.5% for triaging. The confusion matrices confirmed the results. CONCLUSIONS: This study indicates that data enriching by adding NLP-based extraction of the content of referral letters increases the model accuracy of DSSs in suggesting optimal treatments for individual patients with LBP. Overall model accuracies were considered low and insufficient for clinical application.

Central sensitization and functioning in patients with chronic low back pain: A cross-sectional and longitudinal study.

BACKGROUND: Central sensitization (CS) is present in a subgroup of patients with chronic low back pain (CLBP). Studies on the relationship between CS and functioning have limited operationalizations of CS and functioning. OBJECTIVE: To determine whether CS was related to functioning in patients with CLBP (cross-sectional); and to determine whether changes in CS were related to changes in functioning (longitudinal). METHODS: An observational prospective cohort study with data collected at baseline and discharge of an interdisciplinary pain rehabilitation program was executed. CS indicators: CS Inventory part A (CSI-A), quantitative sensory testing (QST), root mean square of successive differences of heart-rate variability (RMSSD). Functioning measures: lifting capacity, physical functioning subscale of Rand36 (Rand36-PF), Work Ability Score (WAS), Pain Disability Index (PDI). Main analyses included correlation and multiple regression controlling for confounders; cross-sectional with baseline data and longitudinal with deltas (Δ). RESULTS: 76 patients with primary CLBP participated at baseline and 56 at discharge. Most associations were weak (cross-sectional r𝑝𝑎𝑟𝑡𝑖𝑎𝑙=-0.30-0.24; longitudinal r𝑝𝑎𝑟𝑡𝑖𝑎𝑙=-0.37-0.44). Cross-sectional multiple regression significant associations: mechanical pain threshold-QST and lifting capacity (r𝑝𝑎𝑟𝑡𝑖𝑎𝑙=-0.39), parasympathetic/vagal tone-RMSSD and physical functioning-Rand36-PF (r𝑝𝑎𝑟𝑡𝑖𝑎𝑙= 0.26). Longitudinal multiple regression significant associations: Δ parasympathetic/vagal tone-RMSSD and Δ lifting capacity (r𝑝𝑎𝑟𝑡𝑖𝑎𝑙= 0.48), ΔCSI-A and Δdisability-PDI (r𝑝𝑎𝑟𝑡𝑖𝑎𝑙= 0.36). Cross-sectional and longitudinal final regression models explained 24.0%-58.3% and 13.3%-38.0% of total variance. CONCLUSION: CS was weakly related to functioning, and decreases in CS were weakly-moderately related to increases in functioning.

Maximal aerobic capacity is associated with lifting capacity, but not with self-reported functioning measures in patients with primary chronic low back pain: a cross-sectional study.

Objective: Maximal exercise testing is considered the gold standard to assess V̇O2max. However, maximal exercise testing was previously deemed unfeasible and unsafe in chronic low back pain (CLBP) patients. Consequently, most previous studies on aerobic capacity and functioning in patients with CLBP were performed with submaximal testing protocols. A recent study demonstrated the safety, feasibility and tolerance of maximal exercise testing in patients with CLBP. Therefore, the relation between aerobic capacity and functioning should be reevaluated. This cross-sectional study aims to determine the relationship between maximal aerobic capacity and four measures of functioning: lifting capacity, work ability, pain-related disability and physical functioning in patients with CLBP. Methods: The maximal aerobic capacity of patients with CLBP was assessed with a maximal cardiopulmonary exercise test. Functioning was measured with a floor-to-waist lifting capacity test and three questionnaires: Work Ability Score, Pain Disability Index and Physical Functioning subscale of RAND-36. The associations between maximal aerobic capacity and each of the functioning measures were analysed with multiple linear regression analyses while controlling for potential confounders. Results: Data of n=74 patients with CLBP were analysed. After controlling for potential confounders, maximal aerobic capacity was moderately associated with lifting capacity (ß=0.32, p=0.006), but not with any of the other functioning measures (ß=-0.08 to 0.12, p>0.288). Conclusion: A higher level of maximal aerobic capacity is moderately associated with a higher lifting capacity, but not with self-reported work ability, pain-related disability and physical functioning.

Validation of the work ability index-single item and the pain disability index-work item in patients with chronic low back pain.

PURPOSE: A cross-sectional and longitudinal study was conducted to analyse construct validity, responsiveness, and Minimal Clinically Important Change (MCIC) in the Work Ability Score (WAS) and Pain Disability Index Work item (PDI-W) in patients with Chronic Low Back Pain (CLBP). METHOD: Construct validity was assessed by testing predefined hypotheses. Responsiveness and MCIC were measured with an anchor-based method. The area under the receiver Operating Characteristic Curve (AUC) and the optimal cut-off point were calculated. Smallest Detectable Change (SDC) was calculated to determine measurement error. RESULTS: In total, 1502 patients (age 18-65 years) with CLBP were included. For validity of the WAS and PDI-W, respectively, seven and six out of 10 hypotheses were not rejected. The WAS (n = 355) was responsive to change with an AUC of 0.70. MCIC was 1.5 point, SDCindividual 4.9, and SDCgroup 0.3. MCICs were 4.5, 1.5, and - 0.5 points for, respectively, low, middle, and high scoring baseline groups. The PDI-W (n = 297) was responsive to change with an AUC of 0.80. MCIC was - 2.5 points, SDCindividual 5.2, and SDCgroup 0.3. MCICs were - 0.5, - 2.5, and - 4.5 points for, respectively, low, middle, and high scoring baseline groups. CONCLUSION: Construct validity of the WAS and PDI-W was insufficient in this patient sample. The WAS and PDI-W are responsive to change. On average, improvements of 1.5 point (WAS) and - 2.5 points (PDI-W) were interpreted as clinically important. However, MCICs are also baseline dependent. Due to a risk of measurement error, at the individual level change scores should be interpreted with caution.

What can we learn from long-term studies on chronic low back pain? A scoping review.

PURPOSE: A scoping review was conducted with the objective to identify and map the available evidence from long-term studies on chronic non-specific low back pain (LBP), to examine how these studies are conducted, and to address potential knowledge gaps. METHOD: We searched MEDLINE and EMBASE up to march 2021, not restricted by date or language. Experimental and observational study types were included. Inclusion criteria were: participants between 18 and 65 years old with non-specific sub-acute or chronic LBP, minimum average follow-up of > 2 years, and studies had to report at least one of the following outcome measures: disability, quality of life, work participation, or health care utilization. Methodological quality was assessed using the Effective Public Health Practice Project quality assessment. Data were extracted, tabulated, and reported thematically. RESULTS: Ninety studies met the inclusion criteria. Studies examined invasive treatments (72%), conservative (21%), or a comparison of both (7%). No natural cohorts were included. Methodological quality was weak (16% of studies), moderate (63%), or strong (21%) and generally improved after 2010. Disability (92%) and pain (86%) outcomes were most commonly reported, followed by work (25%), quality of life (15%), and health care utilization (4%). Most studies reported significant improvement at long-term follow-up (median 51 months, range 26 months-18 years). Only 10 (11%) studies took more than one measurement > 2 year after baseline. CONCLUSION: Patients with persistent non-specific LBP seem to experience improvement in pain, disability and quality of life years after seeking treatment. However, it remains unclear what factors might have influenced these improvements, and whether they are treatment-related. Studies varied greatly in design, patient population, and methods of data collection. There is still little insight into the long-term natural course of LBP. Additionally, few studies perform repeated measurements during long-term follow-up or report on patient-centered outcomes other than pain or disability.

Participants' unspoken thoughts and feelings negatively influence the therapeutic alliance; a qualitative study in a multidisciplinary pain rehabilitation setting.

PURPOSE: This study aimed to explore factors that influence participants' perceptions of the therapeutic alliance with healthcare professionals; their participation in the alliance; and their commitment to treatment in a multidisciplinary pain rehabilitation setting. MATERIALS AND METHODS: A qualitative research-design was used and 26 participants in a multidisciplinary pain rehabilitation program were interviewed in-depth. RESULTS: Initially, participants reported to be satisfied with their healthcare professionals. After deeper reflection on the therapeutic alliance, several unspoken thoughts and feelings and relational ruptures emerged. Almost all participants mentioned a history of disappointing and fragmented healthcare, and they reported on how this affected their cognitions, perceptions, and beliefs about the current program. Participants felt insufficiently empowered to voice their concerns and regularly chose to avoid confrontation by not discussing their feelings. They felt a lack of ownership of their problems and did not experience the program as person-centered. CONCLUSIONS: Several factors were found that negatively influence the quality of therapeutic alliance (agreement on bond) and efficacy of the treatment plan (agreement on goals and tasks). To improve outcomes of pain rehabilitation, healthcare professionals should systematically take into account the perceptions and needs of participants, and focus more on personalized collaboration throughout the program offered.Implications for rehabilitationDifferences in perceptions and experiences of pain, together with differences in beliefs about the causes of pain, negatively influence the therapeutic alliance.When participants and healthcare professionals operate from different paradigms, it is important that they negotiate these differences.From the perspective of participants, a clear-cut organization of healthcare that encourages collaboration is required.It is important to focus on personalized collaboration from the start and during treatment, and to recognize and discuss disagreement on diagnosis and treatment plans.During this collaboration, healthcare professionals should systematically take into account the perceptions and needs of the participants.

Long-term follow-up of patients with chronic musculoskeletal pain attending interdisciplinary pain rehabilitation: outcomes and predictive factors.

The long-term outcomes of interdisciplinary pain rehabilitation (IPR) in patients with chronic musculoskeletal pain (CMP) and its predictors has been studied to a limited extent. In this historical cohort study, functioning, satisfaction with life domains, and pain were assessed at baseline, discharge, and at 6-15 years follow-up. At follow-up, most patients (77%) rated the effects of the IPR as temporarily or persistently positive. The gains in functioning, satisfaction with life domains, and pain made during IPR remained for 6-15 years after the IPR. Patients who were single, retired, or not in work, and those having higher pain and lower functioning at baseline, had lower functioning at follow-up, while patients with traumatic pain disorders had higher functioning at follow-up. Gains made during IPR, particularly gains in social and mental functioning and in pain predicted functioning at follow-up. Treatments and events between discharge and follow-up also influenced the long-term outcome. In conclusion, on average, outcomes achieved during IPR persisted at long-term follow-up. Predictors of a better long-term outcome were mainly baseline characteristics.

Trajectories of Disability and Low Back Pain Impact: 2-year Follow-up of the Groningen Spine Cohort.

STUDY DESIGN: Prospective cohort study. OBJECTIVE: The aim of this study was to identify treatment response trajectories in patients with low back pain (LBP) during and after multidisciplinary care in a tertiary spine center, and to examine baseline patient characteristics that can distinguish trajectories. SUMMARY OF BACKGROUND DATA: Treatment response is often heterogeneous between patients with LBP. Knowledge on key characteristics that are associated with courses of disability could identify patients at risk for less favorable outcome. This knowledge will help improve shared decision-making. METHODS: Adult patients with LBP completed questionnaires on disability (Pain Disability Index) and LBP impact (Impact Stratification of the National Institutes of Health minimal dataset) at baseline, 6, 12, 18, and 24 months' follow-up. Latent class analyses were applied to identify trajectories of disability and LBP impact. Baseline sociodemographic and clinical patient characteristics were compared between trajectory subgroups. RESULTS: Follow-up was available for 996 patients on disability and 707 patients on LBP impact. Six trajectories were identified for both outcome measures. Three disability trajectories remained stable at distinct levels of severity (68% of patients) and three trajectories showed patterns of recovery (32%). For LBP impact there was one stable trajectory (17%), two slightly improving (59%), two recovering (15%), and one with a pattern of recovery and relapse (15%). Significant differences between trajectories were observed for almost all baseline patient characteristics. CONCLUSION: On average, patients show moderate improvements in disability and LBP impact 2 years after visiting a multidisciplinary tertiary spine center. However, latent class analyses revealed that most patients belong to subgroups experiencing stable levels of disability and LBP impact. Differences in baseline patient characteristics were mostly associated with baseline levels of functioning, instead of (un)favorable outcome during follow-up. LEVEL OF EVIDENCE: 2.

Can We Change Health Care Costs in Patients With Complex Back Pain?: Results From a 5-year Before and After Study.

STUDY DESIGN: A before and after study cohort study. OBJECTIVES: The aim of this study was to examine changes in health care costs after multidisciplinary spine care in patients with complex chronic back pain (CBP), to analyze the predictive value of patient and disease characteristics on health care costs, and to study the potential impact of biases concerning the use of real world data. SUMMARY OF BACKGROUND DATA: Due to high direct and indirect societal costs of back pain there is a need for interventions that can assist in reducing the economic burden on patients and society. METHODS: All patients referred to a university-based spine center insured at a major health care insurer in the Netherlands were invited. Personal and disease-related data were collected at baseline. Health care costs were retrieved from the health care insurer from 2 years before to 2 years after intervention. Repeated measures analysis of variances were calculated to study changes in health care costs after intervention. Multivariable regression analyses and cluster robust fixed effect models were applied to predict characteristics on health care costs. To study regression to the mean, a fixed effect model was calculated comparing 2 years before and 2 years post-intervention. RESULTS: In total 428,158 declarations during 4.6 years were filed by 997 participants (128,666 considered CBP-related). CBP-related costs significantly increased during the intervention period and reduced 2 years after the intervention. Total health care costs kept rising. The intervention was associated with a 21% to 34% (P < 0.01) reduction in costs depending on the model used. Reduction in costs was related to being male and lower body mass index. CONCLUSION: This study suggests that reduction in CBP-related health care utilization in patients with complex CBP can be achieved after a multidisciplinary spine intervention. The results are robust to controlling for background characteristics and are unlikely to be fully driven by regression to the mean. LEVEL OF EVIDENCE: 4.

Central Sensitisation and functioning in patients with chronic low back pain: protocol for a cross-sectional and cohort study.

INTRODUCTION: A relevant subsample of patients with chronic low back pain (CLBP) have manifested augmented central pain processing, central sensitisation (CS). Patients with CLBP have limited functioning and participation. Theoretically, physical functioning in patients with CLBP can plausibly be linked to CS; however, evidence to explain such association is scarce. Moreover, there is no gold standard for CS diagnosis. The objectives of the study are: (1) to analyse the association between instruments assessing reference symptoms and signs attributed to CS; (2) to analyse whether reference symptoms and signs attributed to CS are associated with functioning measurement outcomes; and (3) to analyse whether changes (between baseline and discharge) in reference symptoms and signs attributed to CS are related to changes in each of the functioning measurement outcomes. METHODS AND ANALYSIS: A cross-sectional and longitudinal observational study is performed with measurements taken at baseline and discharge of an interdisciplinary rehabilitation programme. A sample size of 110 adult patients with CLBP has been calculated for the study. CS measurements are: Central Sensitisation Inventory, quantitative sensory testing and heart rate variability. Functioning measurements are: lifting capacity, maximal aerobic capacity, accelerometry and reported functioning. Statistical analyses to be performed are: (1) correlation between CS measurements, (2) multiple regression between functioning (dependent variable) and CS measurements (independent variable), and (3) multiple regression between changes in scores of functioning (dependent variable) and CS measurements (independent variable), and corrected for sex and age. ETHICS AND DISSEMINATION: The study obtained the clearance to its implementation from the Medical Research Ethics Committee of the University Medical Center Groningen in July 2017. The results will be disseminated through scientific publications in peer-reviewed journals, presentations at relevant conferences, and reports to stakeholders. TRIAL REGISTRATION NUMBER: NTR7167/NL6980.

Dosage of pain rehabilitation programmes for patients with chronic musculoskeletal pain: a non-inferiority randomised controlled trial.

Purpose: To analyse the effects of interdisciplinary pain rehabilitation programmes with different dosages; care as usual versus short form.Methods: A single blinded, two armed, randomised controlled trial, with non-inferiority design was performed. All patients with chronic musculoskeletal pain referred to an outpatient multidisciplinary pain rehabilitation programme were eligible for this study. Only dosage differed, content was similar. The difference on Pain Disability Index was the primary outcome measure. Four points difference on Pain Disability Index was applied as a non-inferiority margin. Treatment effects within groups were expressed in standardised mean difference and effect sizes were calculated between the groups.Results: Because care as usual was frequently extended, the difference in dosage between groups was limited. The study was stopped prematurely because of an a-priori stopping rule. Interim analyses are presented. Both groups (care as usual n = 58, short form n = 54) improved significantly (mean Pain Disability Index change care as usual: -10.8; short form: -8.3). Mean difference between groups was 2.5 points (95% confidence interval was -2.2 to 7.3). Effect size between groups was 0.2.Conclusions: The 95% confidence interval for the difference in mean pain disability reduction exceeded the upper limit of the non-inferiority margin. The results of the primary analyses of this trial are, therefore, inconclusive. Ancillary analyses revealed that programme dosage was not associated with differences in the disability outcomes. Implications for rehabilitationOptimum dosage of interdisciplinary pain rehabilitation programs is unknown and scarcely studied. This study is the first to analyse dosage as primary aim.Although results are inconclusive, they also suggest that differences in dosage may not automatically lead to differences in effects.Further research is needed to analyse what dosage works for whom; to detect optimum effective and cost-effective dosage of pain rehabilitation programmes.

Assessing discrepancies in outcomes of pain rehabilitation: "these questionnaires don't measure results that are relevant to me".

Background: Pain rehabilitation programs are recommended interventions for patients with chronic pain. Average effect sizes are moderate. Physiatrists, based on clinical experience, argue that the present outcome measures underestimate the outcome of pain rehabilitation programs.Objective: (1) To explore discrepancies and relationships in outcomes of pain rehabilitation. (2) To explore causes of discrepancies from the perspective of patients.Method: A mixed-method, prospective cohort study of patients who participated in pain rehabilitation programs. Outcome measures: Canadian Occupational Performance Measure, Pain Disability Index, a discharge assessment by the physiatrist. Differences and relations were tested. Semi-structured interviews about patients' explanations for discrepancy were performed via telephone.Results: Outcomes of 45/80 patients (56%) were discrepant. When discrepant, effect sizes of the Canadian Occupational Performance Measure and the Pain Disability Index were substantially lower, but the physiatrist-rated outcomes did not differ between discrepant and non-discrepant patients. Common patient-reported explanations for discrepancy were improvement of coping skills and irrelevant (items of) questionnaires.Conclusion: Discrepancies occurred often. When discrepant, physiatrist-rated outcome reflects a more positive outcome compared to the other outcome measures. The results of the interviews suggest that the present outcome measures may not fully capture life domains that are relevant for patients, and may thus underestimate meaningful outcomes.IMPLICATIONS FOR REHABILITATIONPresent standardized outcome measures may not fully capture and may underestimate meaningful outcomes of pain rehabilitation.Outcome measures of pain rehabilitation programs should include a meaningful patient-centered measure.Development of a patient-centered instrument to capture meaningful outcomes of pain rehabilitation is needed.

Personal and Societal Impact of Low Back Pain: The Groningen Spine Cohort.

STUDY DESIGN: Cross-sectional study. OBJECTIVE: The aim of this study was to study the personal and societal impact of low back pain (LBP) in patients admitted to a multidisciplinary spine center. SUMMARY OF BACKGROUND DATA: The socioeconomic burden of LBP is very high. A minority of patients visit secondary or tertiary care because of severe and long-lasting complaints. This subgroup may account for a major part of disability and costs, yet could potentially gain most from treatment. Currently, little is known about the personal and societal burden in patients with chronic complex LBP visiting secondary/tertiary care. METHODS: Baseline data were acquired through patient-reported questionnaires and health insurance claims. Primary outcomes were LBP impact (Impact Stratification, range 8-50), functioning (Pain Disability Index, PDI; 0-70), quality of life (EuroQol-5D, EQ5D; -0.33 to 1.00), work ability (Work Ability Score, WAS; 0-10), work participation, productivity costs (Productivity Cost Questionnaire), and healthcare costs 1 year before baseline. Healthcare costs were compared with matched primary and secondary care LBP samples. Descriptive and inferential statistics were applied. RESULTS: In total, 1502 patients (age 46.3 ±â€Š12.8 years, 57% female) were included. Impact Stratification was 35.2 ±â€Š7.5 with severe impact (≥35) for 58% of patients. PDI was 38.2 ±â€Š14.1, EQ5D 0.39 (interquartile range, IQR: 0.17-0.72); WAS 4.0 (IQR: 1.0-6.0) and 17% were permanently work-disabled. Mean total health care costs (&OV0556;4875, 95% confidence interval [CI]: 4309-5498) were higher compared to the matched primary care sample (n = 4995) (&OV0556;2365, 95% CI: 2219-2526, P < 0.001), and similar to the matched secondary care sample (n = 4993) (&OV0556;4379, 95% CI: 4180-4590). Productivity loss was estimated at &OV0556;4315 per patient (95% CI: 3898-4688) during 6 months. CONCLUSION: In patients seeking multidisciplinary spine care, the personal and societal impact of LBP is very high. Specifically, quality of life and work ability are poor and health care costs are twice as high compared to patients seeking primary LBP care. LEVEL OF EVIDENCE: 3.

The NIH Minimal Dataset for Chronic Low Back Pain: Responsiveness and Minimal Clinically Important Change.

STUDY DESIGN: Prospective cohort study. OBJECTIVE: To analyze responsiveness and minimal clinically important change (MCIC) of the US National Institutes of Health (NIH) minimal dataset for chronic low back pain (CLBP). SUMMARY OF BACKGROUND DATA: The NIH minimal dataset is a 40-item questionnaire developed to increase use of standardized definitions and measures for CLBP. Longitudinal validity of the total minimal dataset and the subscale Impact Stratification are unknown. METHODS: Total outcome scores on the NIH minimal dataset, Dutch Language Version, were calculated ranging from 0 to 100 points with higher scores representing worse functioning. Responsiveness and MCIC were determined with an anchor-based method, calculating the area under the receiver operating characteristics (ROC) curve (AUC) and by determining the optimal cut-off point. Smallest detectable change (SDC) was calculated as a parameter of measurement error. RESULTS: In total 223 patients with CLBP were included. Mean total score on the NIH minimal dataset was 44 ±â€Š14 points at baseline. The total outcome score was responsive to change with an AUC of 0.84. MCIC was 14 points with a sensitivity of 72% and specificity 82%, and SDC was 23 points. Mean total score on Impact Stratification (scale 8-50) was 34.4 ±â€Š7.4 points at baseline, with an AUC of 0.91, an MCIC of 7.5 with a sensitivity 96% of and specificity of 78%, and an SDC of 14 points. CONCLUSION: The longitudinal validity of the NIH minimal dataset is adequate. An improvement of 14 points in total outcome score and 7.5 points in Impact Stratification can be interpreted as clinically important in individual patients. However, MCIC depends on baseline values and the method that is chosen to determine the optimal cut-off point. Furthermore, measurement error is larger than the MCIC. This means that individual change scores should be interpreted with caution. LEVEL OF EVIDENCE: 2.

Dosage of pain rehabilitation programs: a qualitative study from patient and professionals' perspectives.

BACKGROUND: There is a large and unexplained practice variation in prescribed dosages of pain rehabilitation programs (PRP), and evidence regarding the optimum dosage is unknown. METHODS: To explore perspectives of patients and rehabilitation professionals regarding dosages of PRP an explorative qualitative research design was performed with thematic analysis. Patients and rehabilitation professionals were recruited from three rehabilitaton centers in the Netherlands. A purposive sample of patients who completed a PRP, with a range of personal and clinical characteristics was included. Rehabilitation professionals from all different disciplines, working within multidisciplinary PRP for a minimum of two years, for at least 0.5 fte were included. Individual semi-structured interviews were conducted with 12 patients undergoing PRP, and three focus groups were formed with a total of 17 rehabilitation professionals involved in PRP. RESULTS: All patients were satisfied with received dosage. Factors important in relation to dosage of PRP were categorized into patient related characteristics (case complexity from a biopsychosocial perspective) to treatment related characteristics (logistics and format of the program, interaction between patients and professionals), and external factors (support from others, costs, traveling distance and injury compensation). Professionals concluded that dosage was currently based on historical grounds and clinical expertise. CONCLUSION: Patients and professionals from different centers considered the same factors related to dosage of PRP, but these considerations (from patients and professionals) led to different dose choices between centers. PRP dosage appeared to be mainly based on historical grounds and clinical expertise. The insights of this study could assist in future research regarding optimum dosage of PRP and rehabilitation programs in general.

Measurement Properties of the NIH-Minimal Dataset Dutch Language Version in Patients With Chronic Low Back Pain.

STUDY DESIGN: Validation study with cross-sectional and longitudinal measurements. OBJECTIVE: To translate the US National Institutes of Health (NIH)-minimal dataset for clinical research on chronic low back pain into the Dutch language and to test its validity and reliability among people with chronic low back pain. SUMMARY OF BACKGROUND DATA: The NIH developed a minimal dataset to encourage more complete and consistent reporting of clinical research and to be able to compare studies across countries in patients with low back pain. In the Netherlands, the NIH-minimal dataset has not been translated before and measurement properties are unknown. METHODS: Cross-cultural validity was tested by a formal forward-backward translation. Structural validity was tested with exploratory factor analyses (comparative fit index, Tucker-Lewis index, and root mean square error of approximation). Hypothesis testing was performed to compare subscales of the NIH dataset with the Pain Disability Index and the EurQol-5D (Pearson correlation coefficients). Internal consistency was tested with Cronbach α and test-retest reliability at 2 weeks was calculated in a subsample of patients with Intraclass Correlation Coefficients and weighted Kappa (κω). RESULTS: In total, 452 patients were included of which 52 were included for the test-retest study. VALIDITY: factor analysis for structural validity pointed into the direction of a seven-factor model (Cronbach α = 0.78). Factors and total score of the NIH-minimal dataset showed fair to good correlations with Pain Disability Index (r = 0.43-0.70) and EuroQol-5D (r = -0.41 to -0.64). Reliability: test-retest reliability per item showed substantial agreement (κω=0.65). Test-retest reliability per factor was moderate to good (Intraclass Correlation Coefficient = 0.71). CONCLUSION: The Dutch language version measurement properties of the NIH-minimal were satisfactory. LEVEL OF EVIDENCE: N/A.

Cut-Off Points for Mild, Moderate, and Severe Pain on the Numeric Rating Scale for Pain in Patients with Chronic Musculoskeletal Pain: Variability and Influence of Sex and Catastrophizing.

Objectives: The 0-10 Numeric Rating Scale (NRS) is often used in pain management. The aims of our study were to determine the cut-off points for mild, moderate, and severe pain in terms of pain-related interference with functioning in patients with chronic musculoskeletal pain, to measure the variability of the optimal cut-off points, and to determine the influence of patients' catastrophizing and their sex on these cut-off points. Methods: 2854 patients were included. Pain was assessed by the NRS, functioning by the Pain Disability Index (PDI) and catastrophizing by the Pain Catastrophizing Scale (PCS). Cut-off point schemes were tested using ANOVAs with and without using the PSC scores or sex as co-variates and with the interaction between CP scheme and PCS score and sex, respectively. The variability of the optimal cut-off point schemes was quantified using bootstrapping procedure. Results and conclusion: The study showed that NRS scores ≤ 5 correspond to mild, scores of 6-7 to moderate and scores ≥8 to severe pain in terms of pain-related interference with functioning. Bootstrapping analysis identified this optimal NRS cut-off point scheme in 90% of the bootstrapping samples. The interpretation of the NRS is independent of sex, but seems to depend on catastrophizing. In patients with high catastrophizing tendency, the optimal cut-off point scheme equals that for the total study sample, but in patients with a low catastrophizing tendency, NRS scores ≤ 3 correspond to mild, scores of 4-6 to moderate and scores ≥7 to severe pain in terms of interference with functioning. In these optimal cut-off schemes, NRS scores of 4 and 5 correspond to moderate interference with functioning for patients with low catastrophizing tendency and to mild interference for patients with high catastrophizing tendency. Theoretically one would therefore expect that among the patients with NRS scores 4 and 5 there would be a higher average PDI score for those with low catastrophizing than for those with high catastrophizing. However, we found the opposite. The fact that we did not find the same optimal CP scheme in the subgroups with lower and higher catastrophizing tendency may be due to chance variability.

Case complexity in patients with chronic nonspecific musculoskeletal pain: a Delphi and feasibility study.

Assessment of case complexity in patients with chronic nonspecific musculoskeletal pain (CMP) is currently clinician based, not transparent, and with low reliability. The objective of this study was to explore case complexity and to initiate the development of a case complexity index (CCI). A three-round Delphi study among clinicians involved in multidisciplinary Pain Rehabilitation Programs was performed to identify important factors that are assumed to influence functioning in patients with CMP. The 10 most important factors were used to initiate the development of a CCI, with mean ratings of importance per factor as weights. The feasibility of the CCI was tested in a pilot study on 16 patients with CMP. In the first round, 166 factors were identified; in the second round, the 10 most important factors were selected; in the third round, relative weights of each factor were calculated, ranging from 1.75 (features of complaints) to 3.56 (psychiatric disorders) on a scale from 0 (no weight) to 4 (very heavy weight). The assessments for the factors were mainly based on clinical examination and reasoning. Clinicians could rate all patients using the CCI, which confirmed feasibility of the CCI. Ten, mainly psychosocial, factors were identified, which were assumed to be most important for the assessment of case complexity in a patient with CMP. With these factors, a CCI was created, for which feasibility was established. This CCI is transparent, easy to use, and might provide a basis for further development of a structured assessment of case complexity, which may have scientific and clinical relevance.

Predictors of multidisciplinary treatment outcome in patients with chronic musculoskeletal pain.

PURPOSE: The present study aimed to identify predictors of rehabilitation outcome for patients with chronic musculoskeletal pain (CMP) and psychological problems. METHODS: A retrospective cohort study including 230 adult patients with CMP admitted for multidisciplinary pain rehabilitation. Potential predictors were patient characteristics, duration of complaints, baseline functioning, pain, personality, coping style, fear of movement, psychological distress and type of treatment. Outcome measures were physical functioning, mental health, pain and patient-reported effect. Multiple (logistic) regression models were used to identify predictors. RESULTS: Patients who were more disabled and patients with more pain benefitted more from the rehabilitation treatment than less disabled patients or those with less pain. Age, work status, vitality, depression and coping style also predicted outcomes significantly. The models explained between 27 and 80% of the outcomes. There was an interaction between type of treatment, work status and the baseline pain score as regards the outcome in terms of pain. CONCLUSIONS: No strong predictors of treatment outcome were found other than the baseline scores of the respective outcome variables. More disabled patients and patients with more pain benefitted more from the rehabilitation program. Other predictors improved the prediction models slightly. Implications for Rehabilitation It remains challenging to correctly predict the outcome of treatment from patients' baseline sociodemographic and psychological characteristics; predictors other than baseline scores of the outcome variables are only slightly associated with treatment outcome. Patients with chronic musculoskeletal pain and poor physical functioning or mental health benefit most from pain rehabilitation. Older patients benefit less from a pain rehabilitation program than younger patients in terms of physical functioning. Pain reduction during a pain rehabilitation program is greatest in patients with high pain intensity who are not at work at the start of the rehabilitation program. Coping style influences the outcome of rehabilitation of patients with chronic musculoskeletal pain.

Cut-off points for mild, moderate, and severe pain on the visual analogue scale for pain in patients with chronic musculoskeletal pain.

The aim of this study was to find the cut-off points on the visual analogue scale (VAS) to distinguish among mild, moderate, and severe pain, in relation to the following: pain-related interference with functioning; verbal description of the VAS scores; and latent class analysis for patients with chronic musculoskeletal pain. A total of 456 patients were included. Pain was assessed using the VAS and verbal rating scale; functioning was assessed using the domains of the Short Form (36) Health Survey (SF-36). Eight cut-off point schemes were tested using multivariate analysis of variance (MANOVA), ordinal logistic regression, and latent class analysis. The study results showed that VAS scores ⩽ 3.4 corresponded to mild interference with functioning, whereas 3.5 to 6.4 implied moderate interference, and ⩾ 6.5 implied severe interference. VAS scores ⩽ 3.4 were best described for patients with chronic musculoskeletal pain as mild pain, 3.5 to 7.4 as moderate pain, and ⩾ 7.5 as severe pain. Latent class analysis found that a 3-class solution fitted best, resulting in the classes 0.1 to 3.8, 3.9 to 5.7, and 5.8 to 10 cm. Findings from our study agree with those of some other studies, although many other studies found different optimal cut-off point schemes. As there appear to be no universally accepted cut-off points, and in view of the low-to-moderate associations between VAS scores and functioning and between VAS and verbal rating scale scores, the correct classification of VAS scores as mild, moderate. or severe in clinical practice seems doubtful.