H.C.W. de Vet

Responsiveness of functional status in low back pain: a comparison of different instruments.

&NA; This study compares the responsiveness of three instruments of functional status: two disease‐specific questionnaires (Oswestry and Roland Disability Questionnaires), and a patient‐specific method (severity of the main complaint). We compared changes over time of functional status instruments with pain rated on a visual analog scale. Two strategies for evaluating the responsiveness in terms of sensitivity to change and specificity to change were used: effect size statistics and receiver‐operating characteristic method. We chose global perceived effect as external criterion. A cohort of 81 patients with non‐specific low back pain for at least 6 weeks assessed these measures before and after 5 weeks of treatment. According to the external criterion 38 patients improved. The results of both strategies were the same. All instruments were able to discriminate between improvement and non‐improvement. The effect size statistics of the instruments were higher in the improved group than in the non‐improved group. For each instrument the receiver‐operating characteristic curves showed some discriminative ability. The curves for the Roland Questionnaire and pain were closer to the upper left than the curves for the other instruments. The sensitivity to change of the rating of Oswestry Questionnaire was lower than that of the other instruments. The main complaint was not very specific to change. The two strategies for evaluating the responsiveness were very useful and appeared to complement each other.

High physical work load and low job satisfaction increase the risk of sickness absence due to low back pain: Results of a prospective cohort study

Objective: To determine whether physical and psychosocial load at work influence sickness absence due to low back pain. Methods: The research was a part of the study on musculoskeletal disorders, absenteeism, stress, and health (SMASH), a 3 year prospective cohort study on risk factors for musculoskeletal disorders. Workers from 21 companies located throughout The Netherlands participated in the part of this study on sickness absence due to low back pain. The study population consisted of 732 workers with no sickness absences of 3 days or longer due to low back pain in the 3 months before the baseline survey and complete data on the reasons for absences during the follow up period. The mean (range) period of follow up in this group was 37 (7–44) months. Physical load at work was assessed by analyses of video recordings. Baseline information on psychosocial work characteristics was obtained by a questionnaire. Data on sickness absence were collected from company records. The main outcome measure was the rate of sickness absences of 3 days or longer due to low back pain during the follow up period. Results: After adjustment of the work related physical and psychosocial factors for each other and for other potential determinants, significant rate ratios ranging from 2.0 to 3.2 were found for trunk flexion, trunk rotation, lifting, and low job satisfaction. A dose-response relation was found for trunk flexion, but not for trunk rotation or lifting. Non-significant rate ratios of about 1.4 were found for low supervisor support and low coworker support. Quantitative job demands, conflicting demands, decision authority, and skill discretion showed no relation with sickness absence due to low back pain. Conclusions: Flexion and rotation of the trunk, lifting, and low job satisfaction are risk factors for sickness absence due to low back pain. Some indications of a relation between low social support, either from supervisors or coworkers, and sickness absence due to low back pain are also present.

Clinimetric Properties of the Motor Activity Log for the Assessment of Arm Use in Hemiparetic Patients

Background and Purpose— The Motor Activity Log (MAL) is a semistructured interview for hemiparetic stroke patients to assess the use of their paretic arm and hand (amount of use [AOU]) and quality of movement [QOM]) during activities of daily living. Scores range from 0 to 5. The following clinimetric properties of the MAL were quantified: internal consistency (Cronbach α), test–retest agreement (Bland and Altman method), cross-sectional construct validity (correlation between AOU and QOM and with the Action Research Arm [ARA] test), longitudinal construct validity (correlation of change on the MAL during the intervention with a global change rating [GCR] and with change on the ARA), and responsiveness (effect size). Methods— Two baseline measurements 2 weeks apart and 1 follow-up measurement immediately after 2 weeks of intensive exercise therapy either with or without immobilization of the unimpaired arm (forced use) were performed in 56 chronic stroke patients. Results— Internal consistency was high (AOU: α=0.88; QOM: α=0.91). The limits of agreement were −0.70 to 0.85 and −0.61 to 0.71 for AOU and QOM, respectively. The correlation with the ARA score (Spearman ρ) was 0.63 (AOU and QOM). However, the improvement on the MAL during the intervention was only weakly related to the GCR and to the improvement on the ARA, Spearman ρ was between 0.16 and 0.22. The responsiveness ratio was 1.9 (AOU) and 2.0 (QOM). Conclusion— The MAL is internally consistent and relatively stable in chronic stroke patients not undergoing an intervention. The cross-sectional construct validity of the MAL is reasonable, but the results raise doubt about its longitudinal construct validity.

Episodes of Low Back Pain : A Proposal for Uniform Definitions to Be Used in Research

Study Design. Literature review and group discussions. Objective. To propose uniform definitions for low back pain episodes to be used in research. Background. Different definitions of episodes have been used in low back pain studies. This hampers comparison of study results. Definitions are proposed for episodes of low back pain, care for low back pain, and work absence because of low back pain. Methods. In a Medline search, we identified about 1200 papers, of which 81 possibly contained a definition of episodes. In group discussions, we decided which definitions to propose and discussed their applicability. Results. We found few definitions in the literature. In the group discussions we decided to define an episode of LBP as a period of pain in the lower back lasting for more than 24 hours, preceded and followed by a period of at least 1 month without low back pain. An episode of care for low back pain was defined as a consultation or a series of consultations for low back pain, preceded and followed by at least 3 months without consultation for low back pain. An episode of work absence due to low back pain was defined as a period of work absence due to low back pain, preceded and followed by a period of at least 1 day at work. Conclusions. In many studies, episodes of low back pain are mentioned without a clear definition. We consider our proposed definitions of episodes to be arbitrary but well considered. We advise that they be tested for use in future research.

Effectiveness of exercise therapy: A best-evidence summary of systematic reviews

The purpose of this project was to summarise the available evidence on the effectiveness of exercise therapy for patients with disorders of the musculoskeletal, nervous, respiratory, and cardiovascular systems. Systematic reviews were identified by means of a comprehensive search strategy in 11 bibliographic databases (08/2002), in combination with reference tracking. Reviews that included (i) at least one randomised controlled trial investigating the effectiveness of exercise therapy, (ii) clinically relevant outcome measures, and (iii) full text written in English, German or Dutch, were selected by two reviewers. Thirteen independent and blinded reviewers participated in the selection, quality assessment and data-extraction of the systematic reviews. Conclusions about the effectiveness of exercise therapy were based on the results presented in reasonable or good quality systematic reviews (quality score > or = 60 out of 100 points). A total of 104 systematic reviews were selected, 45 of which were of reasonable or good quality. Exercise therapy is effective for patients with knee osteoarthritis, sub-acute (6 to 12 weeks) and chronic (> or = 12 weeks) low back pain, cystic fibrosis, chronic obstructive pulmonary disease, and intermittent claudication. Furthermore, there are indications that exercise therapy is effective for patients with ankylosing spondylitis, hip osteoarthritis, Parkinsons disease, and for patients who have suffered a stroke. There is insufficient evidence to support or refute the effectiveness of exercise therapy for patients with neck pain, shoulder pain, repetitive strain injury, rheumatoid arthritis, asthma, and bronchiectasis. Exercise therapy is not effective for patients with acute low back pain. It is concluded that exercise therapy is effective for a wide range of chronic disorders.

Multidisciplinary rehabilitation for subacute low back pain: graded activity or workplace intervention or both?: a randomized controlled trial

Study design. Population-based randomized controlled trial. Objective. To assess the effectiveness of workplace intervention and graded activity, separately and combined, for multidisciplinary rehabilitation of low back pain (LBP). Summary of Background Data. Effective components for multidisciplinary rehabilitation of LBP are not yet established. Methods. Participants sick-listed 2 to 6 weeks due to nonspecific LBP were randomized to workplace intervention (n = 96) or usual care (n = 100). Workplace intervention consisted of workplace assessment, work modifications, and case management involving all stakeholders. Participants still sick-listed at 8 weeks were randomized for graded activity (n = 55) or usual care (n = 57). Graded activity comprised biweekly 1-hour exercise sessions based on operant-conditioning principles. Outcomes were lasting return to work, pain intensity and functional status, assessed at baseline, and at 12, 26, and 52 weeks after the start of sick leave. Results. Time until return to work for workers with workplace intervention was 77 versus 104 days (median) for workers without this intervention (P = 0.02). Workplace intervention was effective on return to work (hazard ratio = 1.7; 95% CI, 1.2–2.3; P = 0.002). Graded activity had a negative effect on return to work (hazard ratio = 0.4; 95% CI, 0.3–0.6; P < 0.001) and functional status. Combined intervention had no effect. Conclusion. Workplace intervention is advised for multidisciplinary rehabilitation of subacute LBP. Graded activity or combined intervention is not advised.

The quality of diagnostic accuracy studies since the STARD statement Has it improved

Objective: To assess whether the quality of reporting of diagnostic accuracy studies has improved since the publication of the Standards for the Reporting of Diagnostic Accuracy studies (STARD statement). Methods: The quality of reporting of diagnostic accuracy studies published in 12 medical journals in 2000 (pre-STARD) and 2004 (post-STARD) was evaluated by two reviewers independently. For each article, the number of reported STARD items was counted (range 0 to 25). Differences in completeness of reporting between articles published in 2000 and 2004 were analyzed, using multilevel analyses. Results: We included 124 articles published in 2000 and 141 articles published in 2004. Mean number of reported STARD items was 11.9 (range 3.5 to 19.5) in 2000 and 13.6 (range 4.0 to 21.0) in 2004, an increase of 1.81 items (95% CI: 0.61 to 3.01). Articles published in 2004 reported the following significantly more often: methods for calculating test reproducibility of the index test (16% vs 35%); distribution of the severity of disease and other diagnoses (23% vs 53%); estimates of variability of diagnostic accuracy between subgroups (39% vs 60%); and a flow diagram (2% vs 12%). Conclusions: The quality of reporting of diagnostic accuracy studies has improved slightly over time, without a more pronounced effect in journals that adopted the STARD statement. As there is still room for improvement, editors should mention the use of the STARD statement as a requirement in their guidelines for authors, and instruct reviewers to check the STARD items. Authors should include a flow diagram in their manuscript.

Value of symptoms and additional diagnostic tests for colorectal cancer in primary care: systematic review and meta-analysis.

Objective To summarise available evidence on diagnostic tests that might help primary care physicians to identify patients with an increased risk for colorectal cancer among those consulting for non-acute lower abdominal symptoms. Data sources PubMed, Embase, and reference screening. Study eligibility criteria Studies were selected if the design was a diagnostic study; the patients were adults consulting because of non-acute lower abdominal symptoms; tests included signs, symptoms, blood tests, or faecal tests. Study appraisal and synthesis methods Two reviewers independently assessed quality with a modified version of the QUADAS tool and extracted data. We present diagnostic two by two tables and pooled estimates of sensitivity and specificity. We refrained from pooling when there was considerable clinical or statistical heterogeneity. Results 47 primary diagnostic studies were included. Sensitivity was consistently high for age ≥50 (range 0.81-0.96, median 0.91), a referral guideline (0.80-0.94, 0.92), and immunochemical faeces tests (0.70-1.00, 0.95). Of these, only specificity of the faeces tests was good. Specificity was consistently high for family history (0.75-0.98, 0.91), weight loss (0.72-0.96, 0.89), and iron deficiency anaemia (0.83-0.95, 0.92), but all tests lacked sensitivity. None of these six tests was (sufficiently) studied in primary care. Conclusions Although combinations of symptom and results of immunochemical faeces tests showed good diagnostic performance for colorectal cancer, evidence from primary care is lacking. High quality studies on their role in the diagnostic investigation of colorectal cancer in primary care are urgently needed.

Clinicians are right not to like Cohen’s κ

Clinicians are interested in observer variation in terms of the probability of other raters (interobserver) or themselves (intraobserver) obtaining the same answer. Cohen’s κ is commonly used in the medical literature to express such agreement in categorical outcomes. The value of Cohen’s κ, however, is not sufficiently informative because it is a relative measure, while the clinician’s question of observer variation calls for an absolute measure. Using an example in which the observed agreement and κ lead to different conclusions, we illustrate that percentage agreement is an absolute measure (a measure of agreement) and that κ is a relative measure (a measure of reliability). For the data to be useful for clinicians, measures of agreement should be used. The proportion of specific agreement, expressing the agreement separately for the positive and the negative ratings, is the most appropriate measure for conveying the relevant information in a 2×2 table and is most informative for clinicians.

The effectiveness of ergonomic interventions on return-to-work after low back pain; a prospective two year cohort study in six countries on low back pain patients sicklisted for 3–4 months

Aims: To study occurrence and effectiveness of ergonomic interventions on return-to-work applied for workers with low back pain (LBP). Methods: A multinational cohort of 1631 workers fully sicklisted 3–4 months due to LBP (ICD-9 codes 721, 722, 724) was recruited from sickness benefit claimants databases in Denmark, Germany, Israel, Sweden, the Netherlands, and the United States. Medical, ergonomic, and other interventions, working status, and return-to-work were measured using questionnaires and interviews at three months, one and two years after the start of sickleave. Main outcome measure was time to return-to-work. Cox’s proportional hazards model was used to calculate hazard ratios regarding the time to return-to-work, adjusted for prognostic factors. Results: Ergonomic interventions varied considerably in occurrence between the national cohorts: 23.4% (mean) of the participants reported adaptation of the workplace, ranging from 15.0% to 30.5%. Adaptation of job tasks and adaptation of working hours was applied for 44.8% (range 41.0–59.2%) and 46.0% (range 19.9–62.9%) of the participants, respectively. Adaptation of the workplace was effective on return-to-work rate with an adjusted hazard ratio (HR) of 1.47 (95% CI 1.25 to 1.72; p < 0.0001). Adaptation of job tasks and adaptation of working hours were effective on return-to-work after a period of more than 200 days of sickleave with an adjusted HR of 1.78 (95% CI 1.42 to 2.23; p < 0.0001) and 1.41 (95% CI 1.13 to 1.76; p = 0.002), respectively. Conclusions: Results suggest that ergonomic interventions are effective on return-to-work of workers long term sicklisted due to LBP.