Fausto Salaffi

OBJECTIVES: To determine the minimal clinically important difference (MCID) of changes in chronic musculoskeletal pain intensity that is most closely associated with improvement on the commonly used and validated measure of the patient's global impression of change (PGIC), and to estimate the dependency of the MCID on the baseline pain scores. METHODS: This was a prospective cohort study assessing patient's pain intensity by the numerical rating scale (NRS) at baseline and at the 3 month follow-up, and by a PGIC questionnaire. A one unit difference at the lowest end of the PGIC ("slightly better") was used to define MCID as it reflects the minimum and lowest degree of improvement that could be detected. In addition we also calculated the NRS changes best associated with "much better" (two units). In order to characterize the association between specific NRS change scores (raw or percent) and clinically important improvement, the sensitivity and specificity were calculated by the receiver operating characteristic (ROC) method. PGIC was used as an external criterion to distinguish between improved or non-improved patients. RESULTS: 825 patients with chronic musculoskeletal pain (233 with osteoarthritis of the knee, 86 with osteoarthritis of the hip, 133 with osteoarthritis of the hand, 290 with rheumatoid arthritis and 83 with ankylosing spondylitis) were followed up. A consistent relationship between the change in NRS and the PGIC was observed. On average, a reduction of one point or a reduction of 15.0% in the NRS represented a MCID for the patient. A NRS change score of -2.0 and a percent change score of -33.0% were best associated with the concept of "much better" improvement. For this reason these values can be considered as appropriate cut-off points for this measure. The clinically significant changes in pain are non-uniform along the entire NRS. Patients with a high baseline level of pain on the NRS (score of >7 cm), who experienced either a slight improvement or a higher level of response, had absolute raw and percent changes greater that did patients in the lower cohort (score of less than 4 cm). CONCLUSIONS: These results are consistent with the recently published findings generated by different methods and support the use of a "much better" improvement on the pain relief as a clinically important outcome. A further confirmation in other patient populations and different chronic pain syndromes will be needed.

INTRODUCTION: Gender as a predictor of outcomes of rheumatoid arthritis (RA) has evoked considerable interest over the decades. Historically, there is no consensus whether RA is worse in females or males. Recent reports suggest that females are less likely than males to achieve remission. Therefore, we aimed to study possible associations of gender and disease activity, disease characteristics, and treatments of RA in a large multinational cross-sectional cohort of patients with RA called Quantitative Standard Monitoring of Patients with RA (QUEST-RA). METHODS: The cohort includes clinical and questionnaire data from patients who were seen in usual care, including 6,004 patients at 70 sites in 25 countries as of April 2008. Gender differences were analyzed for American College of Rheumatology Core Data Set measures of disease activity, DAS28 (disease activity score using 28 joint counts), fatigue, the presence of rheumatoid factor, nodules and erosions, and the current use of prednisone, methotrexate, and biologic agents. RESULTS: Women had poorer scores than men in all Core Data Set measures. The mean values for females and males were swollen joint count-28 (SJC28) of 4.5 versus 3.8, tender joint count-28 of 6.9 versus 5.4, erythrocyte sedimentation rate of 30 versus 26, Health Assessment Questionnaire of 1.1 versus 0.8, visual analog scales for physician global estimate of 3.0 versus 2.5, pain of 4.3 versus 3.6, patient global status of 4.2 versus 3.7, DAS28 of 4.3 versus 3.8, and fatigue of 4.6 versus 3.7 (P < 0.001). However, effect sizes were small-medium and smallest (0.13) for SJC28. Among patients who had no or minimal disease activity (0 to 1) on SJC28, women had statistically significantly higher mean values compared with men in all other disease activity measures (P < 0.001) and met DAS28 remission less often than men. Rheumatoid factor was equally prevalent among genders. Men had nodules more often than women. Women had erosions more often than men, but the statistical significance was marginal. Similar proportions of females and males were taking different therapies. CONCLUSIONS: In this large multinational cohort, RA disease activity measures appear to be worse in women than in men. However, most of the gender differences in RA disease activity may originate from the measures of disease activity rather than from RA disease activity itself.

BACKGROUND: The health-related quality of life (HRQL) is an important indicator of the burden of musculoskeletal disease. The Medical Outcome Study Short-Term 36 (SF-36) is the most used tool that evaluates HRQL as a subjective perception about psychological and physical limitations due to an underlying illness. The purpose of this study was to compare the HRQL scores among patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA) and ankylosing spondylitis (AS) and a selected sample of health people and determine their relationship with measures of clinical condition. METHODS: 799 patients (469 with RA, 164 with AS, 65 with axial PsA and 101 with peripheral PsA) accepted the invitation to participate. 1579 healthy controls were used for the comparison. We calculated scores for the eight SF-36 subscales, the Physical Component Summary (PCS) score, and the Mental Component Summary (MCS) score, according to published algorithms. Disease-related characteristics included disease duration, comorbidity, a measure for disease activity and for radiographic damage. The presence of comorbidity was ascertained through patient's self-reports by the Self-Administered Comorbidity Questionnaire (SCQ). Comparison were performed with respect to sex and age, and s-scores were calculated for comparison with the norm. Multivariate analyses were used to assess the relationship between HRQL and radiographic damage, disease activity, and socio-demographic data. RESULTS: The four inflammatory rheumatic diseases (IRD), compared to controls, significantly impaired all eight health concepts of the SF-36 (p < 0.0001) in both component PCS and MCS scores (p < 0.0001). Overall, the dimensions typically affected were physical functioning, limitations due to physical function, and bodily pain. The disease with the worst HRQL for those dimensions was RA. The multivariate analyses revealed that the physical component was influenced by a high disease activity and comorbidity. The severity of psoriatic lesions was associated with poor mental functioning in patients with PsA. CONCLUSION: Chronic IRD have a clearly detrimental effect on the HRQL in both sex and in age groups, and physical domain is more impaired than mental and social ones.

OBJECTIVE: The objective of the MAPPING study was to estimate the prevalence of musculoskeletal conditions in an Italian population sample. METHODS: Questionnaires were sent to a random sample of 3664 individuals aged 18 years and over, stratified for age and gender, selected from the practice lists of 16 general practices. Trained rheumatologists carried out structured visits in which subjects were asked about musculoskeletal symptoms and socio-demographic characteristics, and underwent a standardized physical examination. Cases were defined by previously validated criteria. RESULTS: A total of 2155 subjects participated in the study (response rate 58.8%). The overall prevalence of musculoskeletal conditions in the general adult population was 26.7% (95% CI 25.4-28.5), being significantly higher among women than men (p < 0.0001). Disease prevalence increased significantly with age (p < 0.0001). The most common disease group was symptomatic peripheral osteoarthritis (SPOA), with a prevalence of 8.95% (95% CI 6.81-10.7), followed by soft tissue disorders--STD (8.81%; 95% CI 7.16-10.29), low back pain--LBP (5.91%; 95% CI 4.89-6.89), and inflammatory rheumatic disease--IRD (3.06%; 95% CI 2.38-3.93). The estimated rates of disease prevalence were as follows: rheumatoid arthritis: 0.46% (95% CI 0.33-0.59); psoriatic arthritis: 0.42% (95% CI 0.31-0.61); ankylosing spondylitis: 0.37% (95% CI 0.23-0.49); polymyalgia rheumatica: 0.37% (95% CI 0.29-0.44); undifferentiated connective tissue disease: 0.14% (95% CI 0.09-0.21); crystal arthropathies, including gout 0.46% (95% CI 0.34-0.57) and chondrocalcinosis: 0.42% (95% CI 0.33-0.58); symptomatic knee osteoarthritis (OA): 5.39% (95% CI 3.41-7.99); hip-OA: 1.61% (95% CI 1.39-1.87); hand-OA: 1.95 (95% CI 1.22-2.48); fibromyalgia: 2.22% (95% CI 1.36-3.19); shoulder tendinitis/adhesive capsulitis: 3.06% (95% CI 2.11-4.09); carpal tunnel syndrome: 1.90% (95% CI 1.06-2.29), localized regional pain syndromes of the neck: 0.88% (95% CI 0.561.29), and lateral epicondylitis 0.74% (95% CI 0.47-1.33). CONCLUSIONS: The MAPPING study indicates that musculoskeletal conditions are common in the general adult population of Italy. These data are useful in planning the provision of healthcare.