False hyperphosphoremia in multiple myeloma. Interference of monoclonal immunoglobulin G with the determination of blood phosphorus level]

A case of pseudohyperphosphataemia detected in a male patient with multiple IgG myeloma is reported. Phosphataemia, measured by a technique without previous deproteinization, reached 5.66 mM before any treatment and varied with treatment-induced changes in monoclonal immunoglobulin levels. Conversely, normal phosphataemia levels were found in blood samples taken before and after treatment when serum was deproteinized. This pseudohyperphosphataemia resulted from an increase in optic density due to interference between monoclonal immunoglobulin and the molybdic reagent used to determine phosphataemia. A retrospective investigation yielded three similar cases: two in patients with myeloma and one in a patient with non-myelomatous monoclonal dysglobulinaemia. A brief prospective study showed that this phenomenon was relatively frequent, as it was found in 2 out of 9 patients with monoclonal immunoglobulin (IgG in all 9 cases). These data indicate that the finding of marked hyperphosphataemia in subjects with monoclonal dysglobulinaemia should always prompt a control assay performed on deproteinized blood.     

Physical inactivity in patients with rheumatoid arthritis: data from twenty-one countries in a cross-sectional, international study

OBJECTIVE: Regular physical activity is associated with decreased morbidity and mortality. Traditionally, patients with rheumatoid arthritis (RA) have been advised to limit physical exercise. We studied the prevalence of physical activity and associations with demographic and disease-related variables in patients with RA from 21 countries. METHODS: The Questionnaires in Standard Monitoring of Patients with Rheumatoid Arthritis (QUEST-RA) is a cross-sectional study that includes a self-report questionnaire and clinical assessment of nonselected consecutive outpatients with RA who are receiving usual clinical care. Frequency of physical exercise (>or=30 minutes with at least some shortness of breath, sweating) is queried with 4 response options: >or=3 times weekly, 1-2 times weekly, 1-2 times monthly, and no exercise. RESULTS: Between January 2005 and April 2007, a total of 5,235 patients from 58 sites in 21 countries were enrolled in QUEST-RA: 79% were women, >90% were white, mean age was 57 years, and mean disease duration was 11.6 years. Only 13.8% of all patients reported physical exercise>or=3 times weekly. The majority of the patients were physically inactive with no regular weekly exercise: >80% in 7 countries, 60-80% in 12 countries, and 45% and 29% in 2 countries, respectively. Physical inactivity was associated with female sex, older age, lower education, obesity, comorbidity, low functional capacity, and higher levels of disease activity, pain, and fatigue. CONCLUSION: In many countries, a low proportion of patients with RA exercise. These data may alert rheumatologists to motivate their patients to increase physical activity levels.     

Measurement of joint space width and erosion size

Measurement of radiographic abnormalities in metric units has been reported by several investigators during the last 15 years. Measurement of joint space in large joints has been employed in a few trials to evaluate therapy in osteoarthritis. Measurement of joint space width in small joints has been reported by several investigators but has not yet found a place in clinical trials in rheumatoid arthritis or osteoarthritis. We review methods for measuring joint space width in finger, toe, and wrist joints; special attention is given to how the joint edges are found, the method used to measure distance between joint margins, size of an area of the sampled joint, and reproducibility of measurements. Methods for measurement of erosion size, which have had less attention, are briefly discussed.     

The 5-yr HAQ-disability is related to the first year's changes in the narrowing, rather than erosion score in patients with recent-onset rheumatoid arthritis

OBJECTIVE: To evaluate the predictive validity of radiological change on 5-yr disability in rheumatoid arthritis (RA). METHODS: The study was designed to be multicentre, prospective, longitudinal, with a 5-yr follow-up. Participants were RA patients (ACR criteria), with a disease duration of <1 yr at entry. Radiographs of the hands and feet in posteroanterior view at baseline and after 12 months of follow-up (van der Heijde's modification of Sharp method) were used for structural evaluation. Disability was evaluated with Health Assessment Questionnaire (HAQ) at yr 5. Analyses consisted of (i) correlation existing between the changes in the radiological scores during the first year and the HAQ value at yr 5 and (ii) determination of the optimal cut-off in the changes in the radiological scoring system, by ROC curve analysis, in which variable to be explained was disability status at yr 5, defined by HAQ value of at least 1. RESULTS: Due to missing data and/or lost to follow-up, 135 patients (out of the 191 recruited patients) were included in the analyses (mean change in the radiological score = 4.9 +/- 8.7 points, mean HAQ at yr 5 = 0.62 +/- 0.68). There was a statistically significant correlation between the HAQ-disability status at yr 5 and the changes observed in the radiological total damage and narrowing scores during the first year (r = 0.18, P = 0.046 and r = 0.25, P = 0.006, respectively). Conversely, the short-term changes in the erosion score were not correlated with subsequent HAQ-disability (r = 0.084, P = 0.36). A change of at least 2 points in the total X-ray score was considered as optimal (sensitivity, specificity, positive and negative predictive values of 66.7, 53.9, 32.8 and 82.8%, respectively). CONCLUSION: This work shows that early changes in joint damage in patients with recent-onset RA are related to subsequent HAQ-disability. This relationship is due to changes in narrowing, rather than in erosion score, suggesting that the joint narrowing score might be of great importance in the follow-up of RA patients and in the reports of scientific results. The weak performance of the thresholds established using predictive validity for subsequent HAQ-disability compromise their use at the individual level.     

Relevant change in radiological progression in patients with hip osteoarthritis. II. Determination using an expert opinion approach

AIM: To determine the minimum clinically important difference (MCID) in joint space width (JSW) progression in patients with hip osteoarthritis (OA), based upon evaluation by a panel of clinical experts as a gold standard. METHODS: A sample of 298 patients with hip OA was selected from a multicentre, prospective, longitudinal, 3-yr follow-up study. A pelvic radiograph was obtained at entry and after 3 yr. For each film, the narrowest JSW was measured using a 0.1-mm graduated magnifying glass. The difference between baseline and 3-yr follow-up JSW was calculated. Two senior rheumatologists, who were experts in osteoarthritis, evaluated each pair of films and noted whether a clinically relevant deterioration in osteoarthritis stage occurred at 3 yr compared with baseline. Interobserver reliabilities were evaluated using the kappa coefficient and proportions of agreements. Then, for each measured difference in JSW (0.1 mm per 0.1 mm), the sensitivity and specificity for MCID, defined as the assessment of expert 1, expert 2 or a combination of both, were calculated. This allowed us to obtain, from graphic representations of the correct classification probabilities, the best measured JSW threshold, with the maximal true positive and the minimal false positive results. RESULTS: The mean measured change in JSW was -0.63 +/- 0.74 mm. Experts 1 and 2 considered the decrease in JSW to be clinically relevant in 122 (40.9%) and 100 pairs (33.6%) respectively. The proportion of agreements between the experts was 79.9%, with a kappa coefficient of 0.572. The best measured JSW threshold was -0.4 mm for expert 1, expert 2 and the combination of both; sensitivity and specificity were 0.75 and 0.8, 0.71 and 0.72, and 0.75 and 0.7 respectively. CONCLUSION: This study suggests that a change of at least 0.4 mm in the radiological JSW could be considered clinically relevant. Other studies using other sets of patients and other methods are needed for validation.