Validity and Agreement between the 28-Joint Disease Activity Score Based on C-Reactive Protein and Erythrocyte Sedimentation Rate in Patients with Rheumatoid Arthritis.

Objective. To validate the agreement between the 28-joint disease activity score based on erythrocyte sedimentation rate (DAS28-ESR) and the 28-joint disease activity score based on C-reactive protein (DAS28-CRP) in a group of Danish patients with rheumatoid arthritis (RA). Methods. Data from 109 Danish RA patients initiating biologic treatment were analysed at baseline and following one year of treatment. Participants were retrospectively enrolled from a previous cohort study and were considered eligible for this project if CRP and ESR were measured at baseline and at the follow-up visit. To assess the extent of agreement between the two DAS28 definitions, the "European League Against Rheumatism" (EULAR) response criteria based on each definition were calculated with cross-classification. Weighted Kappa (κ) coefficients were calculated, and Bland-Altman plots were used to illustrate degree of agreement between DAS28 definitions. Results. The 75 eligible patients were classified as EULAR good, moderate, and nonresponders with good agreement (61/75; 81%) between DAS28-CRP and DAS28-ESR (κ = 0.75 (95% CI: 0.63 to 0.88)). Conclusions. According to our findings, DAS28-CRP and DAS28-ESR are interchangeable when assessing RA patients and the two versions of DAS28 are comparable between studies.

A comparison of anti-nuclear antibody quantification using automated enzyme immunoassays and immunofluorescence assays.

Anti-nuclear antibodies (ANA) have traditionally been evaluated using indirect fluorescence assays (IFA) with HEp-2 cells. Quantitative immunoassays (EIA) have replaced the use of HEp-2 cells in some laboratories. Here, we evaluated ANA in 400 consecutive and unselected routinely referred patients using IFA and automated EIA techniques. The IFA results generated by two independent laboratories were compared with the EIA results from antibodies against double-stranded DNA (dsDNA), from ANA screening, and from tests of the seven included subantigens. The final IFA and EIA results for 386 unique patients were compared. The majority of the results were the same between the two methods (n = 325, 84%); however, 8% (n = 30) yielded equivocal results (equivocal-negative and equivocal-positive) and 8% (n = 31) yielded divergent results (positive-negative). The results showed fairly good agreement, with Cohen's kappa value of 0.30 (95% confidence interval (CI) = 0.14-0.46), which decreased to 0.23 (95% CI = 0.06-0.40) when the results for dsDNA were omitted. The EIA method was less reliable for assessing nuclear and speckled reactivity patterns, whereas the IFA method presented difficulties detecting dsDNA and Ro activity. The automated EIA method was performed in a similar way to the conventional IFA method using HEp-2 cells; thus, automated EIA may be used as a screening test.

Patient-reported outcomes in polymyalgia rheumatica.

OBJECTIVE: To prospectively evaluate the disease course and the performance of clinical, patient-reported outcome (PRO) and musculoskeletal ultrasound measures in patients with polymyalgia rheumatica (PMR). METHODS: The study population included 85 patients with new-onset PMR who were initially treated with prednisone equivalent dose of 15 mg daily tapered gradually, and followed for 26 weeks. Data collection included physical examination findings, laboratory measures of acute-phase reactants, and PRO measures. Ultrasound evaluation was performed at baseline and Week 26 to assess for features previously reported to be associated with PMR. Response to corticosteroid treatment was defined as 70% improvement in PMR on visual analog scale (VAS). RESULTS: At baseline, 77% had hip pain in addition to shoulder pain and 100% had abnormal C-reactive protein or erythrocyte sedimentation rate. On ultrasound, 84% had shoulder findings and 32% had both shoulder and hip findings. Response to corticosteroid treatment occurred in 73% of patients by Week 4 and was highly correlated with percentage improvement in other VAS measures. Presence of ultrasound findings at baseline predicted response to corticosteroids at 4 weeks. Factor analysis revealed 6 domains that sufficiently represented all the outcome measures: PMR-related pain and physical function, an elevated inflammatory marker, hip pain, global pain, mental function, and morning stiffness. CONCLUSION: PRO measures and inflammatory markers performed well in assessing disease activity in patients with PMR. A minimum set of outcome measures consisting of PRO measures of pain and function and an inflammatory marker should be used in practice and in clinical trials in PMR.