Drug interactions in the treatment of rheumatoid arthritis and psoriatic arthritis.

BACKGROUND: Treating patients with inflammatory joint diseases (rheumatoid arthritis, psoriatic arthritis) according to established treatment algorithms often requires the simultaneous use of three or more medications to relieve symptoms and prevent long-term joint damage as well as disability. OBJECTIVE: To assess and give an overview on drug-drug interactions in the pharmacotherapy of inflammatory joint diseases with regards to their clinical relevance. METHODS: All possible drug combinations were evaluated using three commercially available drug interaction programs. In those cases where only limited/no data were found, a comprehensive hand search of Pubmed was carried out. Finally, the drug-drug interactions of all possible combinations were classified according to evidence-based medicine and a specifically generated relevance-based system. RESULTS: All three interaction software programs showed consistent results. All detected interactions were combined in clearly structured tables. CONCLUSION: A concise overview on drug-drug interactions is given. Especially in more sophisticated cases extensive knowledge of drug interactions supports optimisation of therapy and results in improved patient safety.

Evaluation of the appropriateness of composite disease activity measures for assessment of psoriatic arthritis.

OBJECTIVE: Specific composite indices assessing disease activity in psoriatic arthritis (PsA) have not yet been sufficiently validated. The objective of this study was to identify instruments best reflecting disease activity in PsA. METHODS: Measures for inclusion in clinical trials, as recommended by the OMERACT-7/8 PsA workshops, were assessed. A principal component analysis (PCA) was performed with cross-sectional data of 105 patients with PsA to identify a minimal set of important dimensions for a disease activity assessment tool for PsA. This was compared with components contained in existing composite indices. RESULTS: The PCA revealed four principal components best reflecting disease activity. The first contained patient global and pain assessment; the second contained 66/68 swollen and tender joint counts as main variables; C-reactive protein (CRP) best loaded to the third component; and the fourth was loaded by skin assessment but did not reach significance. When comparing the three significant principal components with items of established composite measures, they were best covered by the Disease Activity Index for Reactive Arthritis (DAREA) which comprises patient pain and global assessments, 66/68 joint counts and CRP. CONCLUSION: Among the currently available indices used in arthritic conditions, the DAREA best reflects the domains found to be important in PsA.

The public neglect of rheumatic diseases: insights from analyses of attendees in a musculoskeletal disease awareness activity.

OBJECTIVES: To obtain data on the care received by individuals counselled during a public health awareness campaign on painful musculoskeletal conditions (MSC). METHODS: Easy non-formal access to rheumatologists/pain specialists was offered using a mobile unit (Rheuma-Bus) at widely accessible sites. Clients were asked to assess their severity of pain using a 100 mm visual analogue scale (VAS). Age, gender, disease duration, diagnosis if known, current and previous treatment as well as tentative diagnoses assigned and recommendations given to each individual by the counselling physicians were recorded. RESULTS: Average (SD) VAS pain rating was 59 (20.6) mm. Approximately 40% of clients had never consulted a physician for their condition before, but had lower pain scores than those who had seen a physician. Patients with inflammatory MSC had higher pain scores than those with non-inflammatory conditions. More than 2% of the clients had a newly detected inflammatory rheumatic disease. CONCLUSIONS: Many individuals having painful MSC seek medical help only when a very high threshold of pain is reached. Even while under treatment, the high mean pain scores suggest neglect of MSC that are not adequately recognised as important contributors to disability and decreased quality of life.

Acute phase reactants add little to composite disease activity indices for rheumatoid arthritis: validation of a clinical activity score.

INTRODUCTION: Frequent assessments of rheumatoid arthritis (RA) disease activity allow timely adaptation of therapy, which is essential in preventing disease progression. However, values of acute phase reactants (APRs) are needed to calculate current composite activity indices, such as the Disease Activity Score (DAS)28, the DAS28-CRP (i.e. the DAS28 using C-reactive protein instead of erythrocyte sedimentation rate) and the Simplified Disease Activity Index (SDAI). We hypothesized that APRs make limited contribution to the SDAI, and that an SDAI-modification eliminating APRs - termed the Clinical Disease Activity Index (CDAI; i.e. the sum of tender and swollen joint counts [28 joints] and patient and physician global assessments [in cm]) - would have comparable validity in clinical cohorts. METHOD: Data sources comprised an observational cohort of 767 RA patients (average disease duration 8.1 +/- 10.6 years), and an independent inception cohort of 106 patients (disease duration 11.5 +/- 12.5 weeks) who were followed prospectively. RESULTS: Our clinically based hypothesis was statistically supported: APRs accounted only for 15% of the DAS28, and for 5% of the SDAI and the DAS28-CRP. In both cohorts the CDAI correlated strongly with DAS28 (R = 0.89-0.90) and comparably to the correlation of SDAI with DAS28 (R = 0.90-0.91). In additional analyses, the CDAI when compared to the SDAI and the DAS28 agreed with a weighted kappa of 0.70 and 0.79, respectively, and comparably to the agreement between DAS28 and DAS28-CRP. All three scores correlated similarly with Health Assessment Questionnaire (HAQ) scores (R = 0.45-0.47). The average changes in all scores were greater in patients with better American College of Rheumatology response (P < 0.0001, analysis of variance; discriminant validity). All scores exhibited similar correlations with radiological progression (construct validity) over 3 years (R = 0.54-0.58; P < 0.0001). CONCLUSION: APRs add little information on top (and independent) of the combination of clinical variables included in the SDAI. A purely clinical score is a valid measure of disease activity and will have its greatest merits in clinical practice rather than research, where APRs are usually always available. The CDAI may facilitate immediate and consistent treatment decisions and help to improve patient outcomes in the longer term.