Mark J. Hancock

Prognosis for patients with chronic low back pain: inception cohort study

Objectives To describe the course of chronic low back pain in an inception cohort and to identify prognostic markers at the onset of chronicity. Design Inception cohort study with one year follow-up. Setting Primary care clinics in Sydney, Australia. Participants The study sample was a subcohort of an inception cohort of 973 consecutive patients presenting to primary care with acute low back pain (<2 weeks’ duration). 406 participants whose pain persisted for three months formed the inception cohort of patients with chronic low back pain. Main outcome measures Outcomes and putative predictors measured at initial presentation, onset of chronicity (study entry), and follow-up at nine and 12 months. Recovery was determined from measures of pain intensity, disability, and work status. The association between potential prognostic factors and time to recovery was modelled with Cox regression. Results Completeness of follow-up was 97% of total person time for all outcomes. The cumulative probability of being pain-free was 35% at nine months and 42% at 12 months and for complete recovery was 35% at nine months and 41% at 12 months. Of the 259 participants who had not recovered from pain related disability at entry to the chronic study, 47% had recovered by 12 months. Previous sick leave due to low back pain, high disability levels or high pain intensity at onset of chronicity, low levels of education, greater perceived risk of persistent pain, and being born outside Australia were associated with delayed recovery. Conclusion More than one third of patients with recent onset, non-radicular chronic low back pain recover within 12 months. The prognosis is less favourable for those who have taken previous sick leave for low back pain, have high disability levels or high pain intensity at onset of chronic low back pain, have lower education, perceive themselves as having a high risk of persistent pain, and were born outside Australia.

Global Perceived Effect scales provided reliable assessments of health transition in people with musculoskeletal disorders, but ratings are strongly influenced by current status

OBJECTIVE The study investigated the test-retest reliability and construct validity of the Global Perceived Effect (GPE) scale in patients with musculoskeletal disorders. STUDY DESIGN AND SETTING Data from seven clinical studies including 861 subjects were used for the analyses. Repeat measures taken at the same attendance and from attendances separated by 24 hours were compared to estimate test-retest reliability. Construct validity was evaluated by examining relationships between pre, post, and change scores in pain and disability measures with GPE measures. RESULTS Intraclass correlation coefficient values of 0.90-0.99 indicate excellent reproducibility of the GPE scale. In all but one data set, change scores on pain and disability measures correlated well (r=0.40-0.74) with GPE; however, post scores nearly always correlated even more strongly (r=0.58-0.84), and pre scores showed much weaker association (r=0.00-0.28). Pre scores accounted for only a small amount of additional R(2) when added to regression models including post score. CONCLUSIONS Test-retest reliability of the GPE is excellent. GPE ratings are strongly influenced by current status, with the effect more obvious as transition time lengthens. This result questions whether transition ratings truly reflect change, or rather just current state. This finding also has implications for the use of GPE ratings as an external criterion of change in clinimetric studies.

The prognosis of acute and persistent low-back pain: a meta-analysis

Background: Although low-back pain is a highly prevalent condition, its clinical course remains uncertain. Our main objective was to systematically review the literature on the clinical course of pain and disability in patients with acute and persistent low-back pain. Our secondary objective was to investigate whether pain and disability have similar courses. Methods: We performed a meta-analysis of inception cohort studies. We identified eligible studies by searching MEDLINE, Embase and CINAHL. We included prospective studies that enrolled an episode-inception cohort of patients with acute or persistent low-back pain and that measured pain, disability or recovery. Two independent reviewers extracted data and assessed methodologic quality. We used mixed models to determine pooled estimates of pain and disability over time. Results: Data from 33 discrete cohorts (11 166 participants) were included in the review. The variance-weighted mean pain score (out of a maximum score of 100) was 52 (95% CI 48–57) at baseline, 23 (95% CI 21–25) at 6 weeks, 12 (95% CI 9–15) at 26 weeks and 6 (95% CI 3–10) at 52 weeks after the onset of pain for cohorts with acute pain. Among cohorts with persistent pain, the variance-weighted mean pain score (out of 100) was 51 (95% CI 44–59) at baseline, 33 (95% CI 29–38) at 6 weeks, 26 (95% CI 20–33) at 26 weeks and 23 (95% CI 16–30) at 52 weeks after the onset of pain. The course of disability outcomes was similar to the time course of pain outcomes in the acute pain cohorts, but the pain outcomes were slightly worse than disability outcomes in the persistent pain cohorts. Interpretation: Patients who presented with acute or persistent low-back pain improved markedly in the first six weeks. After that time improvement slowed. Low to moderate levels of pain and disability were still present at one year, especially in the cohorts with persistent pain.

Assessment of diclofenac or spinal manipulative therapy, or both, in addition to recommended first-line treatment for acute low back pain: a randomised controlled trial

BACKGROUND We aimed to investigate whether the addition of non-steroidal anti-inflammatory drugs or spinal manipulative therapy, or both, would result in faster recovery for patients with acute low back pain receiving recommended first-line care. METHODS 240 patients with acute low back pain who had seen their general practitioner and had been given advice and paracetamol were randomly allocated to one of four groups in our community-based study: diclofenac 50 mg twice daily and placebo manipulative therapy (n=60); spinal manipulative therapy and placebo drug (n=60); diclofenac 50 mg twice daily and spinal manipulative therapy (n=60); or double placebo (n=60). The primary outcome was days to recovery from pain assessed by survival curves (log-rank test) in an intention-to-treat analysis. This trial was registered with the Australian Clinical Trials Registry, ACTRN012605000036617. FINDINGS Neither diclofenac nor spinal manipulative therapy appreciably reduced the number of days until recovery compared with placebo drug or placebo manipulative therapy (diclofenac hazard ratio 1.09, 95% CI 0.84-1.42, p=0.516; spinal manipulative therapy hazard ratio 1.01, 95% CI 0.77-1.31, p=0.955). 237 patients (99%) either recovered or were censored 12 weeks after randomisation. 22 patients had possible adverse reactions including gastrointestinal disturbances, dizziness, and heart palpitations. Half of these patients were in the active diclofenac group, the other half were taking placebo. One patient taking active diclofenac had a suspected hypersensitivity reaction and ceased treatment. INTERPRETATION Patients with acute low back pain receiving recommended first-line care do not recover more quickly with the addition of diclofenac or spinal manipulative therapy.

Epidural Corticosteroid Injections in the Management of Sciatica: A Systematic Review and Meta-analysis

BACKGROUND Existing guidelines and systematic reviews provide inconsistent recommendations on epidural corticosteroid injections for sciatica. Key limitations of existing reviews are the inclusion of trials with active controls of unknown efficacy and failure to provide an estimate of the size of the treatment effect. PURPOSE To determine the efficacy of epidural corticosteroid injections for sciatica compared with placebo. DATA SOURCES International Pharmaceutical Abstracts, PsycINFO, MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and CINAHL. STUDY SELECTION Randomized, placebo-controlled trials assessing the efficacy of epidural corticosteroid injections in participants with sciatica. DATA EXTRACTION Two independent reviewers extracted data and assessed risk of bias. Leg pain, back pain, and disability were converted to common scales from 0 (no pain or disability) to 100 (worst possible pain or disability). Thresholds for clinically important change in the range of 10 to 30 have been proposed for these outcomes. Effects were calculated for short-term (>2 weeks but ≤3 months) and long-term (≥12 months) follow-up. DATA SYNTHESIS Data were pooled with a random-effects model, and the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach was used in summary conclusions. Twenty-five published reports (23 trials) were included. The pooled results showed a significant, although small, effect of epidural corticosteroid injections compared with placebo for leg pain in the short term (mean difference, -6.2 [95% CI, -9.4 to -3.0]) and also for disability in the short term (mean difference, -3.1 [CI, -5.0 to -1.2]). The long-term pooled effects were smaller and not statistically significant. The overall quality of evidence according to the GRADE classification was rated as high. LIMITATION The review included only English-language trials and could not incorporate dichotomous outcome measures into the analysis. CONCLUSION The available evidence suggests that epidural corticosteroid injections offer only short-term relief of leg pain and disability for patients with sciatica. The small size of the treatment effects, however, raises questions about the clinical utility of this procedure in the target population. PRIMARY FUNDING SOURCE None.

Efficacy of paracetamol for acute low-back pain: a double-blind, randomised controlled trial

BACKGROUND Regular paracetamol is the recommended first-line analgesic for acute low-back pain; however, no high-quality evidence supports this recommendation. We aimed to assess the efficacy of paracetamol taken regularly or as-needed to improve time to recovery from pain, compared with placebo, in patients with low-back pain. METHODS We did a multicentre, double-dummy, randomised, placebo controlled trial across 235 primary care centres in Sydney, Australia, from Nov 11, 2009, to March 5, 2013. We randomly allocated patients with acute low-back pain in a 1:1:1 ratio to receive up to 4 weeks of regular doses of paracetamol (three times per day; equivalent to 3990 mg paracetamol per day), as-needed doses of paracetamol (taken when needed for pain relief; maximum 4000 mg paracetamol per day), or placebo. Randomisation was done according to a centralised randomisation schedule prepared by a researcher who was not involved in patient recruitment or data collection. Patients and staff at all sites were masked to treatment allocation. All participants received best-evidence advice and were followed up for 3 months. The primary outcome was time until recovery from low-back pain, with recovery defined as a pain score of 0 or 1 (on a 0-10 pain scale) sustained for 7 consecutive days. All data were analysed by intention to treat. This study is registered with the Australian and New Zealand Clinical Trial Registry, number ACTN 12609000966291. FINDINGS 550 participants were assigned to the regular group (550 analysed), 549 were assigned to the as-needed group (546 analysed), and 553 were assigned to the placebo group (547 analysed). Median time to recovery was 17 days (95% CI 14-19) in the regular group, 17 days (15-20) in the as-needed group, and 16 days (14-20) in the placebo group (regular vs placebo hazard ratio 0·99, 95% CI 0·87-1·14; as-needed vs placebo 1·05, 0·92-1·19; regular vs as-needed 1·05, 0·92-1·20). We recorded no difference between treatment groups for time to recovery (adjusted p=0·79). Adherence to regular tablets (median tablets consumed per participant per day of maximum 6; 4·0 [IQR 1·6-5·7] in the regular group, 3·9 [1·5-5·6] in the as-needed group, and 4·0 [1·5-5·7] in the placebo group), and number of participants reporting adverse events (99 [18·5%] in the regular group, 99 [18·7%] in the as-needed group, and 98 [18·5%] in the placebo group) were similar between groups. INTERPRETATION Our findings suggest that regular or as-needed dosing with paracetamol does not affect recovery time compared with placebo in low-back pain, and question the universal endorsement of paracetamol in this patient group. FUNDING National Health and Medical Research Council of Australia and GlaxoSmithKline Australia.

Low Back Pain and Best Practice Care A Survey of General Practice Physicians

BACKGROUND Acute low back pain (LBP) is primarily managed in general practice. We aimed to describe the usual care provided by general practitioners (GPs) and to compare this with recommendations of best practice in international evidence-based guidelines for the management of acute LBP. METHODS Care provided in 3533 patient visits to GPs for a new episode of LBP was mapped to key recommendations in treatment guidelines. The proportion of patient encounters in which care arranged by a GP aligned with these key recommendations was determined for the period 2005 through 2008 and separately for the period before the release of the local guideline in 2004 (2001-2004). RESULTS Although guidelines discourage the use of imaging, over one-quarter of patients were referred for imaging. Guidelines recommend that initial care should focus on advice and simple analgesics, yet only 20.5% and 17.7% of patients received these treatments, respectively. Instead, the analgesics provided were typically nonsteroidal anti-inflammatory drugs (37.4%) and opioids (19.6%). This pattern of care was the same in the periods before and after the release of the local guideline. CONCLUSIONS The usual care provided by GPs for LBP does not match the care endorsed in international evidence-based guidelines and may not provide the best outcomes for patients. This situation has not improved over time. The unendorsed care may contribute to the high costs of managing LBP, and some aspects of the care provided carry a higher risk of adverse effects.

Self-efficacy is more important than fear of movement in mediating the relationship between pain and disability in chronic low back pain

Pain self-efficacy and fear of movement have been proposed to explain how pain can lead to disability for patients with chronic low back pain. However the extent to which pain self-efficacy and fear of movement mediate the relationship between pain and disability over time has not been investigated. This study aimed to investigate whether pain self-efficacy and/or fear of movement mediate the relationship between pain intensity and disability in patients with recent onset chronic low back pain. In a two-wave longitudinal design, 184 chronic low back pain patients completed measures for pain intensity, disability, pain self-efficacy and fear of movement at baseline and 12months after the onset of chronic low back pain. Regression analyses were used to test the mediational hypothesis. We found that, when measured at the same time, both pain self-efficacy and fear of movement beliefs partially mediated the effects of pain intensity on disability at the onset of chronic low back pain. However, in the longitudinal analyses, only improvements in self-efficacy beliefs partially mediated the relationship between changes in pain and changes in disability over a 12months period. We found no support for the theory that fear of movement beliefs mediate this relationship. Therefore, we concluded that pain self-efficacy may be a more important variable than fear of movement beliefs in terms of understanding the relationship between pain and disability.Pain self‐efficacy and fear of movement have been proposed to explain how pain can lead to disability for patients with chronic low back pain. However the extent to which pain self‐efficacy and fear of movement mediate the relationship between pain and disability over time has not been investigated. This study aimed to investigate whether pain self‐efficacy and/or fear of movement mediate the relationship between pain intensity and disability in patients with recent onset chronic low back pain. In a two‐wave longitudinal design, 184 chronic low back pain patients completed measures for pain intensity, disability, pain self‐efficacy and fear of movement at baseline and 12 months after the onset of chronic low back pain. Regression analyses were used to test the mediational hypothesis. We found that, when measured at the same time, both pain self‐efficacy and fear of movement beliefs partially mediated the effects of pain intensity on disability at the onset of chronic low back pain. However, in the longitudinal analyses, only improvements in self‐efficacy beliefs partially mediated the relationship between changes in pain and changes in disability over a 12 months period. We found no support for the theory that fear of movement beliefs mediate this relationship. Therefore, we concluded that pain self‐efficacy may be a more important variable than fear of movement beliefs in terms of understanding the relationship between pain and disability.

A Guide to Interpretation of Studies Investigating Subgroups of Responders to Physical Therapy Interventions

Many researchers and clinicians believe the effectiveness of existing physical therapy interventions can be improved by targeting the provision of specific interventions at patients who respond best to that treatment. Although this approach has the potential to improve outcomes for some patients, it needs to be implemented carefully because some methods used to identify subgroups can produce biased or misleading results. The aim of this article is to assist readers in assessing the validity and generalizability of studies designed to identify subgroups of responders to physical therapy interventions. The key messages are that subgroups should be identified using high-quality randomized controlled trials, the investigation should be limited to a relatively small number of potential subgroups for which there is a plausible rationale, subgroup effects should be investigated by formally analyzing statistical interactions, and findings of subgroups should be subject to external validation.

Red flags to screen for malignancy and fracture in patients with low back pain: systematic review

Objective To review the evidence on diagnostic accuracy of red flag signs and symptoms to screen for fracture or malignancy in patients presenting with low back pain to primary, secondary, or tertiary care. Design Systematic review. Data sources Medline, OldMedline, Embase, and CINAHL from earliest available up to 1 October 2013. Inclusion criteria Primary diagnostic studies comparing red flags for fracture or malignancy to an acceptable reference standard, published in any language. Review methods Assessment of study quality and extraction of data was conducted by three independent assessors. Diagnostic accuracy statistics and post-test probabilities were generated for each red flag. Results We included 14 studies (eight from primary care, two from secondary care, four from tertiary care) evaluating 53 red flags; only five studies evaluated combinations of red flags. Pooling of data was not possible because of index test heterogeneity. Many red flags in current guidelines provide virtually no change in probability of fracture or malignancy or have untested diagnostic accuracy. The red flags with the highest post-test probability for detection of fracture were older age (9%, 95% confidence interval 3% to 25%), prolonged use of corticosteroid drugs (33%, 10% to 67%), severe trauma (11%, 8% to 16%), and presence of a contusion or abrasion (62%, 49% to 74%). Probability of spinal fracture was higher when multiple red flags were present (90%, 34% to 99%). The red flag with the highest post-test probability for detection of spinal malignancy was history of malignancy (33%, 22% to 46%). Conclusions While several red flags are endorsed in guidelines to screen for fracture or malignancy, only a small subset of these have evidence that they are indeed informative. These findings suggest a need for revision of many current guidelines.