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

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

STUDY DESIGN: Prospective cohort study OBJECTIVE.: 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 socio-demographic 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. CONCLUSIONS: On average, patients show moderate improvements in disability and LBP impact two 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

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

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 113P 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 +/- 12.8 years, 57% female) were included. Impact Stratification was 35.2 +/- 7.5 with severe impact (>= 35) for 58% of patients. PDI was 38.2 +/- 14.1, 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 ((sic)4875, 95% confidence interval [CI]: 4309-5498) were higher compared to the matched primary care sample (n =4995) ((sic)2365, 95% CI: 2219-2526, P <0.001), and similar to the matched secondary care sample (n -4993) ((sic)4379, 95% CI: 4180-4590). Productivity loss was estimated at (sic)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