Rheumatoid Arthritis: Anderson JJ

Boers M, Anderson JJ, Felson DT. · VU University Medical Centre, Amsterdam, The Netherlands. · J Rheumatol. · Pubmed #12734919 No free full text.

Abstract: This article summarizes the process proposed to come to a definition of low disease activity in rheumatoid arthritis (RA). The purpose of this definition is to aid the interpretation of trial and longitudinal study results. A conceptual proposal is "a disease activity state that is deemed a useful treatment target by both physicians and patients." An operant definition can be derived by judgmental (opinion-based) or statistical (data-based) approaches, but the first seems more appropriate. Once a few candidate definitions have been selected, their usefulness and prognostic validity can be tested in longitudinal datasets.

Felson DT, Anderson JJ. · Boston University Arthritis Center, Massachusetts, USA. · J Rheumatol. · Pubmed #11246690 No free full text.

Abstract: We have assessed the discriminant validity of functional status measures and measures that are part of the core set for rheumatoid arthritis. Papers were identified by a systematic literature search in MEDLINE and hand searching of references.

van Gestel AM, Anderson JJ, van Riel PL, Boers M, Haagsma CJ, Rich B, Wells G, Lange ML, Felson DT. · Department of Rheumatology, University Hospital Nijmegen, The Netherlands. · J Rheumatol. · Pubmed #10090187 No free full text.

Abstract: We compared the validity of the American College of Rheumatology (ACR) and the European League of Associations for Rheumatology (EULAR) definitions of response in rheumatoid arthritis (RA) clinical trials. US: ACR and EULAR improvement criteria were calculated in 7 large randomized RA clinical trials. The discriminant validity of the response criteria between treatment groups was studied using the Mantel-Haenszel chi-squared value. To compare both sets of criteria the chi-squared ratio was determined for each trial. Europe: In 2 large randomized RA clinical trials, ACR and EULAR criteria were calculated, once with extensive and once with 28 joint counts. The classification of patients with these 4 criteria were compared with each other using cross tables. We further studied the difference in response between treatment groups per trial, the association of response with patient and investigator assessment of improvement, and the association of response with radiological progression. US: The chi-squared ratio for most trials was close to 1. There was no clear pattern suggesting that the discriminant validity of the ACR criteria was stronger than the discriminant validity of the EULAR definition of response or vice versa. Europe: Conflicting results between ACR and EULAR were present in only 3% of patients in both trials. The discriminant validity of all 4 criteria (ACR and EULAR with reduced and extensive joint counts) was comparable. All criteria were related with the overall assessment of improvement by both investigator and patient. The association with radiographic progression was comparable for EULAR and ACR improvement criteria. There is a high level of agreement between ACR and EULAR improvement classification, and their validity is equivalent. The discriminating potential of the criteria between treatment groups is comparable, as is the association with patient's and investigator's overall assessment and with radiographic progression.

Anderson JJ. · Clinical Epidemiology Research and Training Unit, Boston University Medical Center, 715 Albany Street, Boston Mass 02118, USA. · Stat Methods Med Res. · Pubmed #17338291 No free full text.

Abstract: In recent years, when reporting the results of clinical trials for chronic disease, including rheumatologic conditions, use has been made of dichotomous definitions of improvement, but it is to be expected that continuous definitions would offer improved discrimination between treatment groups. Nevertheless, a well-constructed dichotomous outcome (usually a composite) has advantages of clinical sense and specificity and may, under a variety of realistic conditions, have power that closely approximates that of standard continuous outcome measures. This has been seen for established dichotomous outcome definitions for two rheumatologic conditions, rheumatoid arthritis (RA) and ankylosing spondylitis (AS). Simulation studies performed using multivariate normal generated data that approximates actual trial data for each of RA and AS patients demonstrate the relative power of several dichotomous and continuous outcomes in realistic situations for each of RA and AS. Although the continuous outcomes are typically more powerful than the dichotomous ones, there are some situations in which the power of a well-defined dichotomous outcome approaches or even exceeds that of a continuous outcome based on mean change.

Wells GA, Boers M, Shea B, Brooks PM, Simon LS, Strand CV, Aletaha D, Anderson JJ, Bombardier C, Dougados M, Emery P, Felson DT, Fransen J, Furst DE, Hazes JM, Johnson KR, Kirwan JR, Landewé RB, Lassere MN, Michaud K, Suarez-Almazor M, Silman AJ, Smolen JS, Van der Heijde DM, van Riel PL, Wolfe F, Tugwell PS. · Department of Epidemiology and Community Medicine, University of Ottawa, Ottawa, Ontario, Canada. · J Rheumatol. · Pubmed #16206362 No free full text.

Abstract: Agreement on response criteria in rheumatoid arthritis (RA) has allowed better standardization and interpretation of clinical trial reports. With recent advances in therapy, the proportion of patients achieving a satisfactory state of minimal disease activity (MDA) is becoming a more important measure with which to compare different treatment strategies. The threshold for MDA is between high disease activity and remission and, by definition, anyone in remission will also be in MDA. True remission is still rare in RA; in addition, the American College of Rheumatology definition is difficult to apply in the context of trials. Participants at OMERACT 6 in 2002 agreed on a conceptual definition of minimal disease activity (MDA): "that state of disease activity deemed a useful target of treatment by both the patient and the physician, given current treatment possibilities and limitations." To prepare for a preliminary operational definition of MDA for use in clinical trials, we asked rheumatologists to assess 60 patient profiles describing real RA patients seen in routine clinical practice. Based on their responses, several candidate definitions for MDA were designed and discussed at the OMERACT 7 in 2004. Feedback from participants and additional on-site analyses in a cross-sectional database allowed the formulation of 2 preliminary, equivalent definitions of MDA: one based on the Disease Activity Score 28 (DAS28) index, and one based on meeting cutpoints in 5 out the 7 WHO/ILAR core set measures. Researchers applying these definitions first need to choose whether to use the DAS28 or the core set definition, because although each selects a similar proportion in a population, these are not always the same patients. In both MDA definitions, an initial decision node places all patients in MDA who have a tender joint count of 0 and a swollen joint count of 0, and an erythrocyte sedimentation rate (ESR) no greater than 10 mm. If this condition is not met: * The DAS28 definition places patients in MDA when DAS28 < or = 2.85; * The core set definition places patients in MDA when they meet 5 of 7 criteria: (1) Pain (0-10) < or = 2; (2) Swollen joint count (0-28) < or = 1; (3) Tender joint count (0-28) < or = 1; (4) Health Assessment Questionnaire (HAQ, 0-3) < or = 0.5; (5) Physician global assessment of disease activity (0-10) < or = 1.5; (6) Patient global assessment of disease activity (0-10) < or = 2; (7) ESR < or = 20. This set of 2 definitions gained approval of 73% of the attendees. These (and other) definitions will now be subject to further validation in other databases.

Anderson JJ, Bolognese JA, Felson DT. · Boston University, Boston, Massachusetts 02118, USA. · Arthritis Rheum. · Pubmed #14613263 links to  free full text

Abstract: OBJECTIVE: Isolated studies have suggested that continuous measures of response may be better than predefined, dichotomous definitions (e.g., the American College of Rheumatology 20% improvement criteria [ACR20]) for discriminating between rheumatoid arthritis (RA) treatments. Our goal was to determine the statistical power of predefined dichotomous outcome measures (termed "a priori"), compared with that of continuous measures derived from trial data in which there was no predefined response threshold (termed "data driven"), and to evaluate the sensitivity to change of these measures in the context of different treatments and early versus later-stage disease. In order to generalize beyond results from a single trial, we performed simulation studies. METHODS: We obtained summary data from trials comparing disease-modifying antirheumatic drugs (DMARDs) and from comparative coxib-placebo trials to test the power of 2 a priori outcomes, the ACR20 and improvement of the Disease Activity Score (DDAS), as well as 2 data-driven outcomes. We studied patients with early RA and those with later-stage RA (duration of <4 years and 4-9 years, respectively). We performed simulation studies, using the interrelationship of ACR core set measures in the trials to generate multiple trial data sets consistent with the original data. RESULTS: The data-driven outcomes had greater power than did the a priori measures. The DMARD comparison was more powerful in early disease than in later-stage disease (the sample sizes needed to achieve 80% power for the most powerful test were 64 for early disease versus 100 for later disease), but the coxib-versus-placebo comparison was less powerful in early disease than in later disease (the sample sizes needed to achieve 80% power were 200 and 100, respectively). When the effects of treatment on core set items were small and/or inconsistent, power was reduced, particularly for a less broadly based outcome (e.g., DDAS) compared with the ACR20. CONCLUSION: The simulation studies demonstrate that data-driven outcome definitions can provide better sensitivity to change than does the ACR20 or DDAS. Using such methods would improve power, but at the expense of trial standardization. The studies also show how patient population and treatment characteristics affect the power of specific outcome measures in RA clinical trials, and provide quantification of those effects.

Anderson JJ, Wells G, Verhoeven AC, Felson DT. · Boston University School of Medicine, Massachusetts, USA. · Arthritis Rheum. · Pubmed #10643696 links to  free full text

Abstract: OBJECTIVE: To use individual patient data from rheumatoid arthritis (RA) clinical trials to identify factors that affect the response to treatment as defined by the American College of Rheumatology (ACR) criteria for improvement (the "ACR response"). METHODS: Primary trial data from 14 diverse, randomized, controlled trials of second-line drugs or devices in RA were analyzed. The trials included 11 methotrexate (MTX) trials (5 placebo controlled and 6 comparative, of which 2 were unpublished), 1 combination trial of cyclosporine plus MTX, 1 induction trial of a combination treatment in early RA (the COBRA trial), and 1 placebo-controlled trial of a new device (Prosorba). Both patient factors and disease activity measures (primarily, items from the ACR core criteria set) were available. RESULTS: A total of 1,435 patients (549 in placebo-controlled trials, 886 in comparative trials) were studied. In both active treatment and placebo groups, disease duration had a strong effect on the likelihood of patient response (e.g., with any active treatment, the response rate was 53% for patients with < or =1 year of disease, 43% for 1-2 years' disease duration, 44% for 2-5 years, 38% for 5-10 years, and 35% for > 10 years; P = 0.001). Decreasing response with greater disease duration was seen during treatment with most of the individual active drugs, as well as with placebo. Other factors decreasing the rate of response to treatment included any prior use of a disease-modifying antirheumatic drug (DMARD), higher disease functional class (according to the Steinbrocker criteria), low disease activity (according to patient's global assessment), and female sex. Each ACR core set variable exhibited a diminished response to treatment in patients with long-standing disease. The difference between active treatment and placebo response rates was not affected by disease duration nor by other factors associated with the ACR response. CONCLUSION: RA patients with longer disease duration do not respond as well to treatment compared with patients with early disease, and female sex, prior DMARD use, disease functional class, and disease activity also have effects on the likelihood of patient response to treatment. This has implications for trial interpretation and for the clinical expectations of RA patients.