Obesity and the risk of multiple or severe frequent knee pain episodes: a 4-year follow-up of the ELSA-Brasil MSK cohort.

BACKGROUND/OBJECTIVE: Knee pain is an important health problem due to its high prevalence, negative impact on daily activities and quality of life, and societal burden. While the link between excess weight and knee pain has been well-documented in the literature, many studies are limited to patients with osteoarthritis or use cross-sectional data. This longitudinal study investigated whether overweight and obesity were associated with the frequency and severity of frequent knee pain (FKP) episodes over 4 years in civil servants enrolled in the ELSA-Brasil MSK cohort. METHODS: Knee pain was assessed during baseline face-to-face interviews (2012-2014) and four yearly telephone follow-ups (2015-2019). Disabling FKP episodes or those of moderate to very severe intensity were classified as severe. Multinomial logistic regression models adjusted for confounders were used to test for associations in two participant groups: those with knee pain at baseline (prognosis cohort) and those without knee pain (incidence cohort). RESULTS: A total of 2644 participants were included: 54.2% female, mean age 55.8 (SD 8.8) years. In the incidence cohort (n = 1896), obesity increased the risk of one (OR: 1.63; 95% CI 1.13-2.37) and multiple FKP episodes (OR: 2.61; 95% CI 1.71-3.97), as well as the risk of non-severe (OR: 1.72; 95% CI 1.04-2.84) and severe FKP episodes (OR: 2.10; 95% CI 1.50-2.95). In the prognosis cohort (n = 748), obesity increased the risk of multiple (OR: 2.54; 95% CI 1.60-4.05) and severe FKP episodes (OR: 2.31; 95% CI 1.49-3.59). Overweight presented the same trends but fell short of significance. CONCLUSIONS: These results provide further support that overweight and obesity are important contributors to the incidence and worsening of FKP, and that weight management must be prioritized in multidisciplinary knee pain prevention and treatment programs to reduce the burden of musculoskeletal disorders.

Racial inequalities in the development of multimorbidity of chronic conditions: results from a Brazilian prospective cohort.

BACKGROUND: The occurrence of multimorbidity and its impacts have differentially affected population subgroups. Evidence on its incidence has mainly come from high-income regions, with limited exploration of racial disparities. This study investigated the association between racial groups and the development of multimorbidity and chronic conditions in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil). METHODS: Data from self-reported white, brown (pardos or mixed-race), and black participants at baseline of ELSA-Brasil (2008-2010) who were at risk for multimorbidity were analysed. The development of chronic conditions was assessed through in-person visits and self-reported diagnosis via telephone until the third follow-up visit (2017-2019). Multimorbidity was defined when, at the follow-up visit, the participant had two or more morbidities. Cumulative incidences, incidence rates, and adjusted incidence rate ratios (IRRs) were estimated using Poisson models. RESULTS: Over an 8.3-year follow-up, compared to white participants: browns had a 27% greater incidence of hypertension and obesity; and blacks had a 62% and 45% greater incidence, respectively. Blacks also had 58% more diabetes. The cancer incidence was greater among whites. Multimorbidity affected 41% of the participants, with a crude incidence rate of 57.5 cases per 1000 person-years (ranging from 56.3 for whites to 63.9 for blacks). Adjusted estimates showed a 20% higher incidence of multimorbidity in black participants compared to white participants (IRR: 1.20; 95% CI: 1.05-1.38). CONCLUSIONS: Significant racial disparities in the risk of chronic conditions and multimorbidity were observed. Many associations revealed a gradient increase in illness risk according to darker skin tones. Addressing fundamental causes such as racism and racial discrimination, alongside considering social determinants of health, is vital for comprehensive multimorbidity care. Intersectoral, equitable policies are essential for ensuring health rights for historically marginalized groups.

Uncovering the Relationship Between Statins and Muscle Problems in the ELSA-Brasil MSK Cohort.

PURPOSE: To investigate the association between statins and muscle problems in a highly diverse sample of Brazilian civil servants. METHODS: We conducted a cross-sectional data analysis at baseline of the ELSA-Brasil MSK cohort. Pain was identified through self-reported symptoms in large muscle groups (lower back and/or hips/thighs). Muscle strength was assessed using the five-times-sit-to-stand (FTSTS) and handgrip tests, with weakness defined as the lowest and highest quintiles of age- and sex-stratified handgrip strength and FTSTS performance time, respectively. Multivariable logistic regression analyses were conducted to investigate the association between statin use and muscle pain and weakness. Secondary analyses explored the impact of different types of statins and their duration of use on the response variables. RESULTS: A total of 2156 participants (mean age 55.6 ± SD 8.9, 52.8% women) were included, of whom 21.1% were taking statins and 25.1% reported muscle pain. We found no significant association between statin use and muscle problems. Secondary analysis on different types of statins revealed an association between atorvastatin and muscle weakness, as measured by the five-times-sit-to-stand test (OR 1.94, 95% CI 1.12-3.37), but not by the handgrip test (OR 0.75, 95% CI 0.29-1.42). No evidence was found to support a link between the duration of statin treatment and muscle problems. CONCLUSIONS: This study challenges previous claims of an efficacy-effectiveness gap between experimental and observational literature on statins. The findings indicate that statin use does not contribute to muscular problems.

Racial inequalities in multimorbidity: baseline of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

BACKGROUND: Evidence of multimorbidity has come mainly from high-income regions, while disparities among racial groups have been less explored. This study examined racial differences in multimorbidity in the multiracial cohort of the Longitudinal Study of Adult Health (Estudo Longitudinal de Saúde do Adulto), ELSA-Brasil. METHODS: The study examined baseline (2008-2010) data for 14 099 ELSA-Brasil participants who self-reported being white, mixed-race, or black. A list of 16 morbidities was used to evaluate multimorbidity, operationalised by simple count into ≥ 2, ≥ 3, ≥ 4, ≥ 5 and ≥ 6 morbidities, in addition to evaluating the number of coexisting conditions. Prevalence ratios (PR) were estimated from logistic models and a quantile model was used to examine racial differences graphically in the distribution quantiles for the number of morbidities. RESULTS: Overall prevalence of multimorbidity (≥ 2 morbidities) was 70% and, after controlling for age and sex, was greater among mixed-race and black participants - by 6% (PR: 1.06; 95% CI: 1.03-1.08) and 9% (PR: 1.09; 95% CI: 1.06-1.12), respectively - than among white participants. As the cutoff value for defining multimorbidity was raised, so the strength of the association increased, especially among blacks: if set at ≥ 6 morbidities, the prevalence was 27% greater for those of mixed-race (PR: 1.27; 95% CI: 1.07-1.50) and 47% greater for blacks (PR: 1.47; 95% CI: 1.22-1.76) than for whites. The disparities were smaller in the lower morbidity distribution quantiles and larger in the upper quantiles, indicating a heavier burden of disease, particularly on blacks. CONCLUSIONS: Multimorbidity was common among adults and older adults in a Brazilian cohort, but important racial inequalities were found. Raising the cutoff point for defining multimorbidity revealed stronger associations between race/skin colour and multimorbidity, indicating a higher prevalence of multimorbidity among mixed-race and black individuals than among whites and that the former groups coexisted more often with more complex health situations (with more coexisting morbidities). Interventions to prevent and manage the condition of multimorbidity that consider the social determinants of health and historically discriminated populations in low- and middle-income regions are necessary.

Dose-response associations of clinical markers of obesity and duration of exposure to excess weight with chronic musculoskeletal pain: cross-sectional analysis at baseline of ELSA-Brasil Musculoskeletal cohort.

The objective of this study is to investigate the association of clinical markers of obesity and weight trajectories with chronic musculoskeletal pain (CMP). This is a cross-sectional study using baseline data from ELSA-Brasil MSK cohort. CMP was evaluated at nine body sites (neck, shoulders, upper back, elbows, lower back, wrists/hands, hips/thighs, knees, ankles/feet), and defined as pain lasting > 6 months in the past year. General and abdominal obesity levels were classified according to accepted cut-offs for body mass index (BMI), waist circumference (WC) and waist-height ratio (WHtR). Binomial and multinomial logistic regressions tested for associations with CMP at any site, at ≥ 3 sites (multisite) and in upper + lower limbs + axial skeleton (generalized). A total of 2899 participants (mean age 56.0 ± 8.93) were included, 55.0% reported CMP, 19.1% had multisite, and 10.3% had generalized CMP. After adjustments for sex, age, education, physical activity and depressive symptoms, nearly all the investigated markers of obesity were associated with any CMP, multisite and generalized CMP, with strongest associations being observed for general obesity level II/III: OR 2.08 (95% CI 1.45-2.99), OR 3.19 (95% CI 2.06-4.94) and OR 3.65 (2.18-6.11), respectively. Having excess weight currently or both at age 20 and currently was also associated with all CMP presentations. Associations of greater magnitude were consistently observed at higher obesity levels and longer exposures to excess weight (dose-response). These results may support the contribution of obesity-derived mechanical and inflammatory mechanisms of CMP, and indicate a role for the accumulation of exposure to excess weight across the adult life course.

Measurement properties of Portuguese-Brazil Western Ontario and McMaster Universities osteoarthritis index (WOMAC) for the assessment of knee complaints in Brazilian adults: ELSA-Brasil Musculoskeletal cohort.

Information on measurement properties of translated versions of the Western Ontario and McMaster Universities (WOMAC) osteoarthritis index is still limited. This study investigated the internal consistency, test-retest reliability/agreement, construct validity, and floor and ceiling effects of Portuguese-Brazil WOMAC applied to civil servants at baseline of ELSA-Brasil Musculoskeletal cohort. Each measurement property was evaluated in the overall sample, in the subgroup reporting knee symptoms, and across different sociodemographic strata (except factorial analyses). Separate analyses were performed for pain, stiffness and function dimensions, considering the knee with the worst score (or right knee if same score in both knees). A total of 1740 participants were included (319 completed WOMAC on 2 occasions), mean age 56.0 (standard deviation = 8.9) years, 46.8% male, 42.1% had knee symptoms. In the overall sample, the range of results for WOMAC's dimensions were: internal consistency = cronbach alpha 0.92-0.98; test-retest reliability = intraclass correlation coefficient 0.85-0.97; standard error of measurement (SEM) = 1.38-5.86; smallest detectable change (SDC) = 3.84-16.25; lowest possible score = 38.8%-61.1% (floor effect present); highest possible score = 0.2%-0.9% (ceiling effect absent). Construct validity was confirmed by hypothesis testing and factorial analysis. Results were similar in the symptomatic group, except for higher SEM and SDC, and the absence of floor effects in pain and function dimensions. Portuguese-Brazil WOMAC showed good overall quality in a nonclinical setting. Variability in measurement properties across different strata of the population should be taken into consideration for the design of future studies using WOMAC.

Exercise treatment effect modifiers in persistent low back pain: an individual participant data meta-analysis of 3514 participants from 27 randomised controlled trials.

BACKGROUND: Low back pain is one of the leading causes of disability worldwide. Exercise therapy is widely recommended to treat persistent non-specific low back pain. While evidence suggests exercise is, on average, moderately effective, there remains uncertainty about which individuals might benefit the most from exercise. METHODS: In parallel with a Cochrane review update, we requested individual participant data (IPD) from high-quality randomised clinical trials of adults with our two primary outcomes of interest, pain and functional limitations, and calculated global recovery. We compiled a master data set including baseline participant characteristics, exercise and comparison characteristics, and outcomes at short-term, moderate-term and long-term follow-up. We conducted descriptive analyses and one-stage IPD meta-analysis using multilevel mixed-effects regression of the overall treatment effect and prespecified potential treatment effect modifiers. RESULTS: We received IPD for 27 trials (3514 participants). For studies included in this analysis, compared with no treatment/usual care, exercise therapy on average reduced pain (mean effect/100 (95% CI) -10.7 (-14.1 to -7.4)), a result compatible with a clinically important 20% smallest worthwhile effect. Exercise therapy reduced functional limitations with a clinically important 23% improvement (mean effect/100 (95% CI) -10.2 (-13.2 to -7.3)) at short-term follow-up. Not having heavy physical demands at work and medication use for low back pain were potential treatment effect modifiers-these were associated with superior exercise outcomes relative to non-exercise comparisons. Lower body mass index was also associated with better outcomes in exercise compared with no treatment/usual care. This study was limited by inconsistent availability and measurement of participant characteristics. CONCLUSIONS: This study provides potentially useful information to help treat patients and design future studies of exercise interventions that are better matched to specific subgroups. PROTOCOL PUBLICATION: https://doi.org/10.1186/2046-4053-1-64.

Job stress and chronic low back pain: incidence, number of episodes, and severity in a 4-year follow-up of the ELSA-Brasil Musculoskeletal cohort.

ABSTRACT: We investigated the association between job stress, as assessed by the effort-reward imbalance model, and the incidence of chronic low back pain (CLBP) over a 4-year period. A total of 1733 participants from the ELSA-Brasil Musculoskeletal cohort, who were free from LBP at baseline (2012-2014), were included. Episodes of LBP in the past 30 days, intensity, and the presence of disability were investigated in annual telephone follow-ups (2015-2018). Chronic LBP was defined as episodes of LBP lasting >3 months with at least moderate intensity. We analyzed the incidence of at least one episode of CLBP (yes/no), the number of CLBP episodes (0, 1, ≥2), and CLBP severity/disability (absent, nondisabling, severe/disabling). The association between these outcomes and tertiles of the effort-to-reward ratio, as well as each dimension of the effort-reward imbalance model, was investigated using multinomial logistic and Poisson regression models adjusting for sociodemographic and occupational variables. The cumulative incidence of CLBP over 4 years was 24.8%. High effort-reward imbalance increased the chances of experiencing multiple CLBP episodes and severe/disabling CLBP by 67% (95% confidence interval [CI]: 1.12-2.47) and 70% (95% CI: 1.14-2.53), respectively. High overcommitment increased the incidence of CLBP by 23% (95% CI: 1.01-1.50) and the chances of multiple CLBP episodes and severe/disabling CLBP by 67% (95% CI: 1.11-2.50) and 57% (95% CI: 1.05-2.34), respectively. These results indicate that exposure to job stress is associated with a higher incidence, a greater number of episodes, and increased severity of CLBP over a 4-year period. If this association is causal, measures aimed at reducing exposure to job stress are likely to alleviate the burden of CLBP.

Can we predict response to the McKenzie method in patients with acute low back pain? A secondary analysis of a randomized controlled trial.

PURPOSE: To evaluate whether patients' treatment preferences, characteristics, or symptomatic response to assessment moderated the effect of the McKenzie method for acute low back pain (LBP). METHODS: This study involved a secondary analysis of a previous RCT on the effect of adding the McKenzie method to the recommended first-line care for patients with acute non-specific LBP. 148 patients were randomized to the First-line Care Group (recommended first-line care alone) or the McKenzie Group (McKenzie method in addition to the first-line care) for a 3-week course of treatment. The primary outcome was pain intensity at 3 weeks. The ability of six patient characteristics to identify those who respond best to McKenzie method was assessed using interaction terms in linear regression models. RESULTS: The six investigated potential effect modifiers for response to the McKenzie method did not predict a more favorable response to this treatment. None of the point estimates for effect modification met our pre-specified criterion of clinical importance of a 1 point greater improvement in pain. For five of the six predictors, the 95% CI did not include our criterion for meaningful clinical improvement. CONCLUSION: We were unable to find any clinically useful effect modifiers for patients with acute LBP receiving the McKenzie method.

Prevalence of chronic musculoskeletal disorders in elderly Brazilians: a systematic review of the literature.

BACKGROUND: Population ageing is a worldwide phenomenon that has recently challenged public healthcare systems. The knowledge of the burden of chronic musculoskeletal disorders in elders is still limited, particularly in the developing world. This systematic review aimed to investigate the prevalence of chronic musculoskeletal disorders in elderly Brazilians. METHODS: A comprehensive literature search was performed in five electronic databases (from inception to January 2012) and completed by additional searches in reference lists. Two review authors independently selected the eligible studies and extracted data on participants' characteristics and rates of chronic musculoskeletal disorders. One review author extracted methodological quality data. We performed a critical synthesis of the results, which were grouped into the diagnoses "chronic musculoskeletal pain" or "specific musculoskeletal diagnoses". RESULTS: Twenty five studies reporting on a total of 116,091 elderly Brazilians were included. Eight studies (32%) were of high methodological quality. There was a large variation in the measure of prevalence used by individual studies and in their definition of chronic pain. Prevalence estimates reached 86% for chronic musculoskeletal pain in any location. Studies investigating multiple pain sites found the lower limb and the spine to be the most prevalent complaints (50% each). Arthritis and rheumatism (including osteoarthritis) were the most prevalent specific musculoskeletal diagnoses (9% to 40%), followed by herniated disc (6% to 27%). CONCLUSIONS: Despite the growth of the elderly population worldwide, high-quality research on the burden of chronic musculoskeletal disorders in the elderly is still scarce. Future healthcare research focusing on this age group should be a priority in developing countries since their public healthcare systems are not yet fully prepared to accommodate the needs of an aging population.

Cost-effectiveness of guideline-endorsed treatments for low back pain: a systematic review.

Healthcare costs for low back pain (LBP) are increasing rapidly. Hence, it is important to provide treatments that are effective and cost-effective. The purpose of this systematic review was to investigate the cost-effectiveness of guideline-endorsed treatments for LBP. We searched nine clinical and economic electronic databases and the reference list of relevant systematic reviews and included studies for eligible studies. Economic evaluations conducted alongside randomised controlled trials investigating treatments for LBP endorsed by the guideline of the American College of Physicians and the American Pain Society were included. Two independent reviewers screened search results and extracted data. Data extracted included the type and perspective of the economic evaluation, the treatment comparators, and the relative cost-effectiveness of the treatment comparators. Twenty-six studies were included. Most studies found that interdisciplinary rehabilitation, exercise, acupuncture, spinal manipulation or cognitive-behavioural therapy were cost-effective in people with sub-acute or chronic LBP. Massage alone was unlikely to be cost-effective. There were inconsistent results on the cost-effectiveness of advice, insufficient evidence on spinal manipulation for people with acute LBP, and no evidence on the cost-effectiveness of medications, yoga or relaxation. This review found evidence supporting the cost-effectiveness of the guideline-endorsed treatments of interdisciplinary rehabilitation, exercise, acupuncture, spinal manipulation and cognitive-behavioural therapy for sub-acute or chronic LBP. There is little or inconsistent evidence for other treatments endorsed in the guideline.

Cost-effectiveness of general practice care for low back pain: a systematic review.

Care from a general practitioner (GP) is one of the most frequently utilised healthcare services for people with low back pain and only a small proportion of those with low back pain who seek care from a GP are referred to other services. The aim of this systematic review was to evaluate the evidence on cost-effectiveness of GP care in non-specific low back pain. We searched clinical and economic electronic databases, and the reference list of relevant systematic reviews and included studies to June 2010. Economic evaluations conducted alongside randomised controlled trials with at least one GP care arm were eligible for inclusion. Two reviewers independently screened search results and extracted data. Eleven studies were included; the majority of which conducted a cost-effectiveness or cost-utility analysis. Most studies investigated the cost-effectiveness of usual GP care. Adding advice, education and exercise, or exercise and behavioural counselling, to usual GP care was more cost-effective than usual GP care alone. Clinical rehabilitation and/or occupational intervention, and acupuncture were more cost-effective than usual GP care. One study investigated the cost-effectiveness of guideline-based GP care, and found that adding exercise and/or spinal manipulation was more cost-effective than guideline-based GP care alone. In conclusion, GP care alone did not appear to be the most cost-effective treatment option for low back pain. GPs can improve the cost-effectiveness of their treatment by referring their patients for additional services, such as advice and exercise, or by providing the services themselves.

Responsiveness of the 24-, 18- and 11-item versions of the Roland Morris Disability Questionnaire.

Several versions of the 24-item Roland Morris Disability Questionnaire (RMDQ) have been proposed; however, their responsiveness has not been extensively explored. The objective of this study was to compare the responsiveness of four versions of the RMDQ. Perceived disability was measured using the 24-item, two 18-item and an 11-item RMDQ on 1,069 low back pain patients from six randomised controlled trials. Responsiveness was calculated using effect size, Guyatt's responsiveness index (GRI) and receiver operating characteristics (ROC) curves. Effect size analyses showed that both 18-item versions of the RMDQ were superior to the 24- and 11-item versions of the RMDQ. GRI showed that the 24- and 18-item versions of the RMDQ were similar but more responsive than the 11-item. ROC curves revealed that the 11-item was less responsive than the other three versions, which had similar responsiveness. The results of this study demonstrate that the 24-item and both 18-item versions of the RMDQ have similar responsiveness with all having superior responsiveness to the 11-item.

The effectiveness of the McKenzie method in addition to first-line care for acute low back pain: a randomized controlled trial.

BACKGROUND: Low back pain is a highly prevalent and disabling condition worldwide. Clinical guidelines for the management of patients with acute low back pain recommend first-line treatment consisting of advice, reassurance and simple analgesics. Exercise is also commonly prescribed to these patients. The primary aim of this study was to evaluate the short-term effect of adding the McKenzie method to the first-line care of patients with acute low back pain. METHODS: A multi-centre randomized controlled trial with a 3-month follow-up was conducted between September 2005 and June 2008. Patients seeking care for acute non-specific low back pain from primary care medical practices were screened. Eligible participants were assigned to receive a treatment programme based on the McKenzie method and first-line care (advice, reassurance and time-contingent acetaminophen) or first-line care alone, for 3 weeks. Primary outcome measures included pain (0-10 Numeric Rating Scale) over the first seven days, pain at 1 week, pain at 3 weeks and global perceived effect (-5 to 5 scale) at 3 weeks. Treatment effects were estimated using linear mixed models. RESULTS: One hundred and forty-eight participants were randomized into study groups, of whom 138 (93%) completed the last follow-up. The addition of the McKenzie method to first-line care produced statistically significant but small reductions in pain when compared to first-line care alone: mean of -0.4 points (95% confidence interval, -0.8 to -0.1) at 1 week, -0.7 points (95% confidence interval, -1.2 to -0.1) at 3 weeks, and -0.3 points (95% confidence interval, -0.5 to -0.0) over the first 7 days. Patients receiving the McKenzie method did not show additional effects on global perceived effect, disability, function or on the risk of persistent symptoms. These patients sought less additional health care than those receiving only first-line care (P = 0.002). CONCLUSIONS: When added to the currently recommended first-line care of acute low back pain, a treatment programme based on the McKenzie method does not produce appreciable additional short-term improvements in pain, disability, function or global perceived effect. However, the McKenzie method seems to reduce health utilization although it does not reduce patient's risk of developing persistent symptoms. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry: ACTRN12605000032651.

Prevalence of pain and associated factors in Brazilian civil servants: an introductory analysis using baseline data from the ELSA-Brasil cohort.

INTRODUCTION: In Brazil, the prevalence and costs of pain will increase substantially with population ageing. Understanding of pain epidemiology is needed for the development of health care policies that can minimize this projected burden. OBJECTIVE: To investigate the prevalence of pain and associated factors at baseline of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil). METHODS: Data were collected in public institutions of higher education/research (2008-2010). Pain in the past 30 days and pain attributed to psychological distress ("with psychological attributions"-PPA) were evaluated by the Clinical Interview Schedule-Revised (CIS-R). The independent t-test and χ2 test investigated associations between sociodemographic/clinical factors and each pain episode. Multivariable analyses including age, sex, leisure-time physical activity, depression, and arthritis/rheumatism, and factors showing univariate associations at the P < 0.10 level, were performed. RESULTS: Fifteen thousand ninety-five civil servants were included (52.1 ± 9.1 years, 54.4% female). The prevalence of any pain was 62.4% (95% confidence interval 61.6%-63.2%), and of PPA was 22.8% (95% confidence interval 22.2%-23.5%). Factors associated with any pain and PPA in multivariable analyses included age (odds ratio [OR] 0.97), female sex (OR 1.86-2.01), moderate and vigorous leisure-time physical activity (OR 0.60-0.84), excessive drinking (OR 0.68-0.83), depressive symptoms (OR 1.28-1.96), anxiety symptoms (OR 1.63-2.45), sleep disturbance (OR 1.62-1.79), and arthritis/rheumatism (OR 1.32-2.18). Nonroutine nonmanual occupation (manual occupation as reference), body mass index, and smoking were independently associated with either any pain or PPA. CONCLUSION: This study provided preliminary information on the epidemiology of pain at baseline of the largest Latin American cohort on chronic noncommunicable diseases.

Trial methodology and patient characteristics did not influence the size of placebo effects on pain.

OBJECTIVE: To determine whether trial-design, patient-type, or placebo-type factors influence the size of the placebo analgesic effect in clinical trials. STUDY DESIGN AND SETTING: Trials that measured pain outcomes in Hróbjartsson and Gøtzsche's meta-analysis were retrieved and coded for eight factors potentially predictive of placebo effect size. Random effects meta-regression was used to explore the predictive power of each factor on placebo effect size. The factors investigated aspects of trial design (nonstandardized co-analgesia, co-intervention), patients (pain type, patient group, residual pain score), and placebo (placebo type, indistinguishability, structural equivalence). The meta-analysis undertaken in the original study was also repeated to confirm the results. RESULTS: The pooled effect of placebo was 3.2 points on a 100-point scale (95% confidence interval [CI]=1.6-4.7). None of the selected factors influenced the size of placebo effect: the effect of all factors was close to zero, all CIs spanned 0, and P-values ranged from 0.13 to 0.90. CONCLUSION: This study confirms the findings of previous researchers that, at present, the evidence for large placebo analgesic effects in clinical trials is lacking. Importantly, this analysis also establishes that larger placebo effects are not associated with particular aspects of the trial methodology, patient, or placebo type.

Correlates of a Recent History of Disabling Low Back Pain in Community-dwelling Older Persons: The Pain in the Elderly (PAINEL) Study.

OBJECTIVES: To investigate the correlates of a recent history of disabling low back pain (LBP) in older persons. MATERIALS AND METHODS: The Pain in the Elderly (PAINEL) Study was derived from the Frailty among Brazilian Older Adults (FIBRA) Network Study. Data were collected through face-to-face/telephone interviews and clinical examination. A series of logistic regressions assessed associations between a recent history of disabling LBP and sociodemographic, physical/lifestyle, and psychological factors. RESULTS: Of the 378 community-dwelling elders included in the study (age±SD, 75.5±6.1), 9.3% experienced LBP that was bad enough to limit or change their daily activities during the past year. Those reporting a recent history of disabling LBP were more likely to be women and under financial strain, to present poor self-rated health, overweight, multimorbidity, low physical activity level, fatigue, depressive symptomatology/diagnosis and fear beliefs, and to report decreased sleep time, prolonged sitting time, chronic pain (in location other than lower back), and frequently recurring LBP. The multivariate logistic regression analysis indicated that overweight (odds ratio [OR], 29.6; 95% confidence interval [CI], 2.3-391.0), low physical activity level (OR, 4.4; 95% CI, 1.3-15.4), fatigue (OR, 10.3; 95% CI, 2.4-43.4), depression diagnosis (OR, 4.9; 95% CI, 1.3-18.4), and frequently recurring LBP (OR, 4.6; 95% CI, 1.0-20.1) were independently associated with a recent history of disabling LBP. DISCUSSION: Our study supports the link between disabling LBP and other age-related chronic conditions in a middle-income country with a rapidly aging population.

Fixed-flexion knee radiography using a new positioning device produced highly repeatable measurements of joint space width: ELSA-Brasil Musculoskeletal Study (ELSA-Brasil MSK).

OBJECTIVE: To describe the performance of a non-fluoroscopic fixed-flexion PA radiographic protocol with a new positioning device, developed for the assessment of knee osteoarthritis (OA) in Brazilian Longitudinal Study of Adult Health Musculoskeletal Study (ELSA-Brasil MSK). MATERIAL AND METHODS: A test-retest design including 19 adults (38 knee images) was conducted. Feasibility of the radiographic protocol was assessed by image quality parameters and presence of radioanatomic alignment according to intermargin distance (IMD) values. Repeatability was assessed for IMD and joint space width (JSW) measured at three different locations. RESULTS: Approximately 90% of knee images presented excellent quality. Frequencies of nearly perfect radioanatomic alignment (IMD ≤1mm) ranged from 29% to 50%, and satisfactory alignment was found in up to 71% and 76% of the images (IMD ≤1.5mm and ≤1.7mm, respectively). Repeatability analyses yielded the following results: IMD [SD of mean difference=1.08; coefficient of variation (%CV)=54.68%; intraclass correlation coefficient (ICC) (95%CI)=0.59 (0.34-0.77)]; JSW [SD of mean difference=0.34-0.61; %CV=4.48%-9.80%; ICC (95%CI)=0.74 (0.55-0.85)-0.94 (0.87-0.97)]. Adequately reproducible measurements of IMD and JSW were found in 68% and 87% of the images, respectively. CONCLUSIONS: Despite the difficulty in achieving consistent radioanatomic alignment between subsequent radiographs in terms of IMD, the protocol produced highly repeatable JSW measurements when these were taken at midpoint and 10mm from the medial extremity of the medial tibial plateau. Therefore, measurements of JSW at these locations can be considered adequate for the assessment of knee OA in ELSA-Brasil MSK.

Psychometric properties of Multidimensional Health Locus of Control - A and General Self-Efficacy Scale in civil servants: ELSA-Brasil Musculoskeletal Study (ELSA-Brasil MSK).

BACKGROUND: Health-related control and self-efficacy beliefs can be assessed in the general population using Multidimensional Health Locus of Control-A subscales (MHLC-A) and the General Self-Efficacy Scale (GSES), respectively. OBJECTIVE: To test construct validity, internal consistency, reliability (test-retest) and ceiling and floor effects of Portuguese-Brazil versions of MHLC-A and GSES. METHOD: Civil servants (N=2901) enrolled in a large Brazilian cohort were included. A new version of the GSES was produced (GSES-Brazil). Procedures for cross-cultural adaptation and testing of psychometric properties followed well-accepted international guidelines. RESULTS: Confirmatory factor analyses yielded the following indices: MHLC-A (tridimensional model): χ2[df]=223.45[132], p-value <0.01; CFI=0.87; TLI=0.85; RMSEA=0.07 (0.07-0.08); WRMR=3.00. GSES-Brazil (unidimensional model): χ2[df]=788.60[35], p-value <0.01; CFI=0.95; TLI=0.94; RMSEA=0.09 (0.08-0.09); WRMR=2.50. Cronbach's alpha coefficients and Intraclass Correlation Coefficients (ICC2,1) ranged from 0.57 (0.54-0.59) and 0.57 (0.47-0.65) for MHLC-A internality to 0.80 (0.79-0.81) and 0.71 (0.66-0.77) for GSES-Brazil, respectively. There was no evidence of ceiling and floor effects. Convergent validity analyses provided further support for construct validity of both scales. CONCLUSION: These findings support the use of the newly developed version of GSES-Brazil for the assessment of general self-efficacy of adult Brazilians. Internal consistency was lower than ideal for MHLC-A, indicating these subscales may need further refinements to provide a more psychometrically sound measure of control beliefs.

The McKenzie Method for the management of acute non-specific low back pain: design of a randomised controlled trial [ACTRN012605000032651].

BACKGROUND: Low back pain (LBP) is a major health problem. Effective treatment of acute LBP is important because it prevents patients from developing chronic LBP, the stage of LBP that requires costly and more complex treatment. Physiotherapists commonly use a system of diagnosis and exercise prescription called the McKenzie Method to manage patients with LBP. However, there is insufficient evidence to support the use of the McKenzie Method for these patients. We have designed a randomised controlled trial to evaluate whether the addition of the McKenzie Method to general practitioner care results in better outcomes than general practitioner care alone for patients with acute LBP. METHODS/DESIGN: This paper describes the protocol for a trial examining the effects of the McKenzie Method in the treatment of acute non-specific LBP. One hundred and forty eight participants who present to general medical practitioners with a new episode of acute non-specific LBP will be randomised to receive general practitioner care or general practitioner care plus a program of care based on the McKenzie Method. The primary outcomes are average pain during week 1, pain at week 1 and 3 and global perceived effect at week 3. DISCUSSION: This trial will provide the first rigorous test of the effectiveness of the McKenzie Method for acute non-specific LBP.