Liseth Siemons

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Objective: Although treat-to-target (T2T) strategies are effective in early RA patients, important individual variations exist in the course towards remission. Growth mixture modeling (GMM) provides more insight into this heterogeneity by identifying subgroups of patients with similar response patterns. This study aimed to identify distinct trajectories of(More)
BACKGROUND The erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) are two commonly used measures of inflammation in rheumatoid arthritis (RA). As current RA treatment guidelines strongly emphasize early and aggressive treatment aiming at fast remission, optimal measurement of inflammation becomes increasingly important. Dependencies with age,(More)
This paper aims to examine the interchangeability of the disease activity score in 28 joints (DAS28)-erythrocyte sedimentation rate (ESR) and DAS28-CRP scores in a diverse sample of rheumatoid arthritis (RA) patients and to evaluate generalizability over gender, age, and disease duration. A sample of 682 patients was drawn from the DREAM registry. Agreement(More)
BACKGROUND Previous studies in patients with hip and knee osteoarthritis (OA) have advocated the relevance of assessing the number of painful joint sites, other than the primary affected joint, in both research and clinical practice. However, it is unclear whether joint-pain comorbidities can simply be summed up. METHODS A total of 401 patients with hip(More)
Title:How age and sex affect the erythrocyte sedimentation rate and C-reactive protein in early rheumatoid arthritis. This study attempts to determine the impact of age, gender and BMI on the erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP) in early rheumatoid arthritis. The findings are of interest but such studies are challenging to(More)
OBJECTIVE To improve the assessment of physical function by enhancing precision of physical function assessment as it pertains to subjects at extreme ends of the health continuum (i.e., subjects with extremely poor function ["floor"] or extremely good health ["ceiling"]). METHODS Under the Patient-Reported Outcomes Measurement Information System (PROMIS)(More)
OBJECTIVE To examine the construct validity of the 28-tender joint count (TJC-28) using item response theory (IRT)-based methods. METHODS A total of 457 patients with early stage rheumatoid arthritis (RA) were included. Internal construct validity of the TJC-28 was evaluated by determining whether the TJC-28 fit a 2-measure logistic IRT model. As well, we(More)
BACKGROUND Although item response theory (IRT) appears to be increasingly used within health care research in general, a comprehensive overview of the frequency and characteristics of IRT analyses within the rheumatic field is lacking. An overview of the use and application of IRT in rheumatology to date may give insight into future research directions and(More)
OBJECTIVE To evaluate the contribution of assessing forefoot joints to the measurement range and measurement precision of joint counts in early rheumatoid arthritis (RA) using item response theory. METHODS Baseline measures of tender and swollen joint counts were analyzed in 459 early RA patients from the Dutch Rheumatoid Arthritis Monitoring remission(More)
OBJECTIVE The aim of this study was to identify baseline predictors of achieving patient-perceived satisfactory improvement (PPSI) in pain after 6 months of treat to target in patients with early RA. METHODS Baseline and 6 month data were used from patients included in the Dutch Rheumatoid Arthritis Monitoring remission induction cohort study. Simple and(More)