Correlation of measures of pain, function, and overall response: results pooled from two identical studies of etoricoxib in chronic low back pain

Usefulness of a global rating change scale for contact lens discomfort evaluation

OBJECTIVES

To evaluate the usefulness of a global rate of change scale (GRCS) to detect variations in contact lens discomfort (CLD).

METHODS

Symptomatic contact lens (CL) wearers were recruited according to the 'Contact Lens Dry Eye Questionnaire-8' (CLDEQ-8). At the baseline visit, subjects scored their comfort following insertion of their habitual CL using a 0-100 visual analogue scale (VAS). After 4-10 h of CL wear, comfort was again self-evaluated with the VAS and with a GRCS (range, -50 to +50). Then, a daily disposable CL (DDCL) was fitted. After one month of DDCL wear, a follow-up visit was conducted where the same evaluations as the baseline visit were performed. Changes in comfort were estimated using a Student's t-test for normal variables and the Friedman test for multiple comparisons of non-parametric variables. Internal responsiveness was measured by calculating the standardised response mean. Agreement between scales was estimated by the intraclass correlation coefficient (ICC).

RESULTS

Twenty-nine (22 females and 7 males) CL wearers with a mean age of 23.4 ± 5.4 years participated in the study. There was a significant decrease in comfort at both visits detected by the GRCS (baseline = -13.58 ± 17.48, p < 0.001; follow up = -6.86 ± 12.69, p = 0.007). However, the VAS did not detect that change, either at baseline (insertion = 64.28 ± 18.72 vs removal = 52.89 ± 17.64, p = 1.000) or follow-up visit (insertion = 81.97 ± 12.91 vs removal = 76.48 ± 16.02, p = 1.000). Comfort at insertion and removal times was significantly higher with the DDCL (p = 0.008 at insertion and p = 0.004 at removal). The standardised response mean was greater with the GRCS than the VAS at baseline (0.78 vs 0.63) and follow-up (0.54 vs 0.37) visits. Agreement between both scales was moderate and significant (p < 0.001) for both visits, ICC: 0.674 (95 % confidence interval (CI):0.411-0.833) (baseline) and 0.652 (95 % CI:0.377-0.821) (follow-up visit).

CONCLUSIONS

The GRCS can detect slight changes in CL wear comfort and shows higher responsiveness than the VAS. This subjective scale can allow detection of changes in comfort in a simple and quick way.

Minimum clinically important differences in chronic pain vary considerably by baseline pain and methodological factors: systematic review of empirical studies

BACKGROUND

The minimum clinically important difference (MCID) is used to interpret the relevance of treatment effects, e.g., when developing clinical guidelines, evaluating trial results or planning sample sizes. There is currently no agreement on an appropriate MCID in chronic pain and little is known about which contextual factors cause variation.

METHODS

This is a systematic review. We searched PubMed, EMBASE, and Cochrane Library. Eligible studies determined MCID for chronic pain based on a one-dimensional pain scale, a patient-reported transition scale of perceived improvement, and either a mean change analysis (mean difference in pain among minimally improved patients) or a threshold analysis (pain reduction associated with best sensitivity and specificity for identifying minimally improved patients). Main results were descriptively summarized due to considerable heterogeneity, which were quantified using meta-analyses and explored using subgroup analyses and metaregression.

RESULTS

We included 66 studies (31.254 patients). Median absolute MCID was 23 mm on a 0-100 mm scale (interquartile range [IQR] 12-39) and median relative MCID was 34% (IQR 22-45) among studies using the mean change approach. In both cases, heterogeneity was very high: absolute MCID I² = 99% and relative MCID I² = 96%. High variation was also seen among studies using the threshold approach: median absolute MCID was 20 mm (IQR 15-30) and relative MCID was 32% (IQR 15-41). Absolute MCID was strongly associated with baseline pain, explaining approximately two-thirds of the variation, and to a lesser degree with the operational definition of minimum pain relief and clinical condition. A total of 15 clinical and methodological factors were assessed as possible causes for variation in MCID.

CONCLUSIONS

MCID for chronic pain relief vary considerably. Baseline pain is strongly associated with absolute, but not relative, measures. To a much lesser degree, MCID is also influenced by the operational definition of relevant pain relief and possibly by clinical condition. Explicit and conscientious reflections on the choice of an MCID are required when classifying effect sizes as clinically important or trivial.

Choosing the right outcome measurement instruments for patients with low back pain

Choosing the most fit-for-purpose outcome measurement instruments is fundamental because using inappropriate instruments can lead to detection bias and measurement inconsistency. Recent recommendations, consensus procedures and systematic reviews on existing patient-reported outcome measures (PROMs) informed this manuscript, which provides suggestions on which outcome domains and measurement instruments to use in patients with low back pain (LBP). Six domains are identified as highly relevant: (1) physical functioning, (2) pain intensity, (3) health-related quality of life, (4) work, (5) psychological functioning and (6) pain interference. For each domain, one or more PROMs are suggested for clinical research and practice, selecting among those that are most frequently used and recommended, and that have satisfactory measurement properties in patients with LBP. Further research on the measurement properties of these suggested PROMs is needed while also considering other emerging instruments, such as the PROMIS computerised adaptive testing and short forms.

Evaluation of the Etoricoxib-Mediated Pain-Relieving Effect in Patients Undergoing Lumbar Fusion Procedures for Degenerative Lumbar Scoliosis: A Prospective Randomized, Double-Blind Controlled Study

This randomized, double-blind study was carried out to evaluate the effectiveness of etoricoxib in controlling the pain during lumbar fusion surgery of the degenerative lumbar scoliosis patients. We found that perioperative use of etoricoxib produced a significant reduction in the degree of pain compared to the patients treated with placebo. Etoricoxib eased the pain and helped to manage the discomfort of lumbar fusion surgery. In addition, etoricoxib was well tolerated as it caused no serious adverse reaction, suggesting a safe profile. Etoricoxib also appeared to ensure and promote the positive effect of surgery, however, insignificantly. Thus, the results suggest that etoricoxib was effective in safely managing the pain during the lumbar fusion surgery and recovery thereafter.

A multifaceted workplace intervention for low back pain in nurses' aides: a pragmatic stepped wedge cluster randomised controlled trial

This study established the effectiveness of a workplace multifaceted intervention consisting of participatory ergonomics, physical training, and cognitive-behavioural training (CBT) for low back pain (LBP). Between November 2012 and May 2014, we conducted a pragmatic stepped wedge cluster randomised controlled trial with 594 workers from eldercare workplaces (nursing homes and home care) randomised to 4 successive time periods, 3 months apart. The intervention lasted 12 weeks and consisted of 19 sessions in total (physical training [12 sessions], CBT [2 sessions], and participatory ergonomics [5 sessions]). Low back pain was the outcome and was measured as days, intensity (worst pain on a 0-10 numeric rank scale), and bothersomeness (days) by monthly text messages. Linear mixed models were used to estimate the intervention effect. Analyses were performed according to intention to treat, including all eligible randomised participants, and were adjusted for baseline values of the outcome. The linear mixed models yielded significant effects on LBP days of -0.8 (95% confidence interval [CI], -1.19 to -0.38), LBP intensity of -0.4 (95% CI, -0.60 to -0.26), and bothersomeness days of -0.5 (95% CI, -0.85 to -0.13) after the intervention compared with the control group. This study shows that a multifaceted intervention consisting of participatory ergonomics, physical training, and CBT can reduce LBP among workers in eldercare. Thus, multifaceted interventions may be relevant for improving LBP in a working population.

Efficacy and safety of paracetamol for spinal pain and osteoarthritis: systematic review and meta-analysis of randomised placebo controlled trials

OBJECTIVE

To investigate the efficacy and safety of paracetamol (acetaminophen) in the management of spinal pain and osteoarthritis of the hip or knee.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Medline, Embase, AMED, CINAHL, Web of Science, LILACS, International Pharmaceutical Abstracts, and Cochrane Central Register of Controlled Trials from inception to December 2014.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Randomised controlled trials comparing the efficacy and safety of paracetamol with placebo for spinal pain (neck or low back pain) and osteoarthritis of the hip or knee.

DATA EXTRACTION

Two independent reviewers extracted data on pain, disability, and quality of life. Secondary outcomes were adverse effects, patient adherence, and use of rescue medication. Pain and disability scores were converted to a scale of 0 (no pain or disability) to 100 (worst possible pain or disability). We calculated weighted mean differences or risk ratios and 95% confidence intervals using a random effects model. The Cochrane Collaboration's tool was used for assessing risk of bias, and the GRADE approach was used to evaluate the quality of evidence and summarise conclusions.

RESULTS

12 reports (13 randomised trials) were included. There was "high quality" evidence that paracetamol is ineffective for reducing pain intensity (weighted mean difference -0.5, 95% confidence interval -2.9 to 1.9) and disability (0.4, -1.7 to 2.5) or improving quality of life (0.4, -0.9 to 1.7) in the short term in people with low back pain. For hip or knee osteoarthritis there was "high quality" evidence that paracetamol provides a significant, although not clinically important, effect on pain (-3.7, -5.5 to -1.9) and disability (-2.9, -4.9 to -0.9) in the short term. The number of patients reporting any adverse event (risk ratio 1.0, 95% confidence interval 0.9 to 1.1), any serious adverse event (1.2, 0.7 to 2.1), or withdrawn from the study because of adverse events (1.2, 0.9 to 1.5) was similar in the paracetamol and placebo groups. Patient adherence to treatment (1.0, 0.9 to 1.1) and use of rescue medication (0.7, 0.4 to 1.3) was also similar between groups. "High quality" evidence showed that patients taking paracetamol are nearly four times more likely to have abnormal results on liver function tests (3.8, 1.9 to 7.4), but the clinical importance of this effect is uncertain.

CONCLUSIONS

Paracetamol is ineffective in the treatment of low back pain and provides minimal short term benefit for people with osteoarthritis. These results support the reconsideration of recommendations to use paracetamol for patients with low back pain and osteoarthritis of the hip or knee in clinical practice guidelines.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration number CRD42013006367.

A randomized, double-blind, placebo-controlled trial of eszopiclone for the treatment of insomnia in patients with chronic low back pain

STUDY OBJECTIVES

Insomnia, which is very common in patients with chronic low back pain (LBP), has long been viewed as a pain symptom that did not merit specific treatment. Recent data suggest that adding insomnia therapy to pain-targeted treatment should improve outcome; however, this has not been empirically tested in LBP or in any pain condition treated with a standardized pain medication regimen. We sought to test the hypothesis that adding insomnia therapy to pain-targeted treatment might improve sleep and pain in LBP.

DESIGN

Double-blind, placebo-controlled, parallel-group, 1-mo trial.

SETTING

Duke University Medical Center Outpatient Sleep Clinic.

PATIENTS

Fifty-two adult volunteers with LBP of at least 3 mo duration who met diagnostic criteria for insomnia (mean age: 42.5 y; 63% females).

INTERVENTIONS

Subjects were randomized to eszopiclone (ESZ) 3 mg plus naproxen 500 mg BID or matching placebo plus naproxen 500 mg twice a day.

MEASUREMENTS AND RESULTS

ESZ SIGNIFICANTLY IMPROVED TOTAL SLEEP TIME (MEAN INCREASE: ESZ, 95 min; placebo, 9 min) (primary outcome) and nearly all sleep measures as well as visual analog scale pain (mean decrease: ESZ, 17 mm; placebo, 2 mm) (primary pain outcome), and depression (mean Hamilton Depression Rating Scale improvement ESZ, 3.8; placebo, 0.4) compared with placebo. Changes in pain ratings were significantly correlated with changes in sleep.

CONCLUSIONS

The addition of insomnia-specific therapy to a standardized naproxen pain regimen significantly improves sleep, pain, and depression in patients with chronic low back pain (LBP). The findings indicate the importance of administering both sleep and pain-directed therapies to patients with LBP in clinical practice and provide strong evidence that improving sleep disturbance may improve pain.

TRIAL REGISTRATION

clinicaltrials.gov identifier: NCT00365976.

Enhanced therapeutic alliance modulates pain intensity and muscle pain sensitivity in patients with chronic low back pain: an experimental controlled study

BACKGROUND

Physical therapy influences chronic pain by means of the specific ingredient of an intervention as well as contextual factors including the setting and therapeutic alliance (TA) between provider and patient.

OBJECTIVE

The purpose of this study was to compare the effect of enhanced versus limited TA on pain intensity and muscle pain sensitivity in patients with chronic low back pain (CLBP) receiving either active or sham interferential current therapy (IFC).

DESIGN

An experimental controlled study with repeated measures was conducted. Participants were randomly divided into 4 groups: (1) AL (n=30), which included the application of active IFC combined with a limited TA; (2) SL (n=29), which received sham IFC combined with a limited TA; (3) AE (n=29), which received active IFC combined with an enhanced TA; and (4) SE (n=29), which received sham IFC combined with an enhanced TA.

METHODS

One hundred seventeen individuals with CLBP received a single session of active or sham IFC. Measurements included pain intensity as assessed with a numerical rating scale (PI-NRS) and muscle pain sensitivity as assessed via pressure pain threshold (PPT).

RESULTS

Mean differences on the PI-NRS were 1.83 cm (95% CI=14.3-20.3), 1.03 cm (95% CI=6.6-12.7), 3.13 cm (95% CI=27.2-33.3), and 2.22 cm (95% CI=18.9-25.0) for the AL, SL, AE, and SE groups, respectively. Mean differences on PPTs were 1.2 kg (95% CI=0.7-1.6), 0.3 kg (95% CI=0.2-0.8), 2.0 kg (95% CI=1.6-2.5), and 1.7 kg (95% CI=1.3-2.1), for the AL, SL, AE, and SE groups, respectively.

LIMITATIONS

The study protocol aimed to test the immediate effect of the TA within a clinical laboratory setting.

CONCLUSIONS

The context in which physical therapy interventions are offered has the potential to dramatically improve therapeutic effects. Enhanced TA combined with active IFC appears to lead to clinically meaningful improvements in outcomes when treating patients with CLBP.

The relationship between pain, disability, quality of life and cognitive-behavioural factors in chronic back pain

PURPOSE

This pilot study systematically examined the correlations between the outcome variables pain intensity, disability and health-related quality of life (HRQOL) and between these outcomes and known psychological risk factors for chronic low back pain (CLBP), such as depression, trait anxiety, avoidance- and endurance-related pain responses at two different assessment points.

METHOD

Data from 52 CLBP inpatients treated in an orthopedic clinic were investigated at two points in time: during the first days after admission and 6 months after the termination of the inpatient treatment. Bivariate relationships between pain intensity, disability, HRQOL and psychological variables were examined with the help of Pearson product moment correlations. Furthermore, the differences that exist between correlations at baseline and follow-up were tested for significance.

RESULTS

Significant and large differences were found between the correlations with low correlations at baseline and high correlations at the follow-up. Furthermore, HRQOL showed a positive correlation with endurance-related and a negative correlation with avoidance-related pain responses.

CONCLUSIONS

Focusing on a systematic comparison of two significant assessment time points in CLBP with an acute exacerbation at baseline, the results of this study underlined the recurrent course of LBP. The results highlight that the assessment time points play an important role in CLBP.

IMPLICATIONS FOR REHABILITATION

• Low back pain is a major public health problem with high direct and indirect back-pain-related costs. • Chronic low back pain is a disabling disease which restricts quality of life. • Psychological factors may have a larger impact on disability and quality of life than pain itself. • The recurrent course of low back pain highlights the importance of multidisciplinary pain management even during acute exacerbations of pain.

A critical review of methods used to determine the smallest worthwhile effect of interventions for low back pain

OBJECTIVE

To critically and systematically review methods used to estimate the smallest worthwhile effect of interventions for nonspecific low back pain.

STUDY DESIGN AND SETTING

A computerized search was conducted of MEDLINE, CINAHL, LILACS, and EMBASE up to May 2011. Studies were included if they were primary reports intended to measure the smallest worthwhile effect of a health intervention (although they did not need to use this terminology) for nonspecific low back pain.

RESULTS

The search located 31 studies, which provided a total of 129 estimates of the smallest worthwhile effect. The estimates were given a variety of names, including the Minimum Clinically Important Difference, Minimum Important Difference, Minimum Worthwhile Reductions, and Minimum Important Change. Most estimates were obtained using anchor- or distribution-based methods. These methods are not (or not directly) based on patients' perceptions, are not intervention-specific, and are not formulated in terms of differences in outcomes with and without intervention.

CONCLUSION

The methods used to estimate the smallest worthwhile effect of interventions for low back pain have important limitations. We recommend that the benefit-harm trade-off method be used to estimate the smallest worthwhile effects of intervention because it overcomes these limitations.

Sources of sacroiliac region pain: insights gained from a study comparing standard intra-articular injection with a technique combining intra- and peri-articular injection

OBJECTIVES

To present evidence supporting the existence of extra-articular sources for sacroiliac region pain and to present evidence that intra-articular anesthetic blockade may underestimate the true prevalence of sacroiliac region pain.

DESIGN

Retrospective review of 2 large case series comparing patient responses to intra-articular injection versus combined intra-articular and peri-articular injection of anesthetic and corticosteroid.

SETTING

Private practice chronic pain clinic set in a hospital outpatient clinic.

PARTICIPANTS

Patients (N=120) sequentially enrolled from practice billing records. Inclusion criteria included pain in the low back below L4 and in the buttock, thigh, groin, or lower leg. If disk herniation, lumbar stenosis, or facet syndrome was previously treated with appropriately chosen injections, response to treatment had to be negative. Patients failed to respond to treatment with physical therapy. Exclusion criteria included records with an incomplete database, patients increasing pain medication use greater than 15% for pain not related to the sacroiliac region, severe psychiatric illness, and nonspecific anesthetic blockade. One hundred sixty-seven records were reviewed to obtain the 120 study subjects.

INTERVENTIONS

Intra-articular injection was done according to the standard technique described by Fortin. Peri-articular injection was done by a slight modification of the procedure described by Yin.

MAIN OUTCOME MEASURES

Percentage change in visual analog scale (VAS) pain scores at 3 weeks and 3 months postinjection; patients' self reported activities of daily living (ADLs) improvement at 3 weeks and 3 months postinjection; and percentage change in VAS pain score within 1 hour of injection.

RESULTS

For intra-articular injection alone, the rate of positive response at 3 months was 12.50% versus 31.25% for the combined injection (P=.025). Positive response was defined as greater than 50% drop in VAS pain score or patients describing ADLs as "greatly improved." Anesthetic response rates were higher in the combined injection group (62.5% vs 42.5%; P=.037).

CONCLUSIONS

Significant extra-articular sources of sacroiliac region pain exist. Intra-articular diagnostic blocks underestimate the prevalence of sacroiliac region pain.

Responder analysis and correlation of outcome measures: pooled results from two identical studies comparing etoricoxib, celecoxib, and placebo in osteoarthritis

OBJECTIVES

To determine the proportion of responders in two identical osteoarthritis (OA) trials using Outcome Measures in Arthritis Clinical Trials-Osteoarthritis Research Society International (OMERACT-OARSI) criteria and to assess the comparability and correlation of individual component measurements.

METHODS

Data were pooled from two identical 26-week, double-blind, randomized, parallel, multicenter trials comparing once daily etoricoxib 30 mg (N=475), celecoxib 200 mg (N=488), and placebo (N=244) in patients with OA of the knee or hip. OMERACT-OARSI criteria were (1) improvement in pain or physical function > or =50% and an absolute change > or =20 mm on a 100-mm visual analog scale (VAS); or (2) improvement of > or =20% and with an absolute change > or =10 mm in at least two of the following three categories: pain, physical function, and patient's global assessment. Correlations were assessed between endpoints measured as time-weighted average change from baseline over 12 weeks using Pearson's correlation coefficient (r).

RESULTS

There were significantly greater proportions of responders in the etoricoxib (66.2%) and celecoxib (63.5%) groups compared with the placebo group (43.0%; P<0.001). There was no difference between the two active treatment groups. There was high correlation between pain and physical function (r=0.903), pain and global assessment (r=0.778), and physical function and global assessment (r=0.820). There was high sensitivity (75-87%) and specificity (80-96%) for changes in individual component measurements to predict OMERACT-OARSI responders.

CONCLUSIONS

Significantly more patients receiving etoricoxib or celecoxib than placebo were OMERACT-OARSI responders. The high correlation between individual scales composing this composite response measurement suggests some redundancies between individual components, particularly between pain and physical function.