Liseth Siemons

Performance of the Dutch SF-36 version 2 as a measure of health-related quality of life in patients with rheumatoid arthritis

BackgroundThe aim of this study was to examine the measurement properties of the Dutch SF-36 version 2 (SF-36v2) health survey in patients with rheumatoid arthritis (RA).MethodsScaling assumptions, internal reliability, and internal construct validity were examined using available data from 1884 RA patients included in the Dutch Rheumatoid Arthritis Monitoring (DREAM) registry. External construct validity and responsiveness to change were examined using baseline and 6-month follow-up data from a subset of 387 early RA patients participating in the DREAM remission induction cohort.ResultsThe individual items of the SF-36v2 adequately met scaling assumptions, although four items correlated too highly with items from different scales. Internal consistency was high for all eight scales and the physical and mental health components underlying the scales were replicated, supporting the use of the standard scoring algorithms. The SF-36v2 scales demonstrated minimal floor effects and ceiling effects were noteworthy only for the role-physical, social functioning, and role-emotional scales. Correlations with other core measures were as expected and the SF-36v2 showed excellent known-groups validity in distinguishing between patients with low or moderate-high disease activity. All scales related to physical health showed moderate to large responsiveness to change in patients that achieved low disease activity at six months.ConclusionThe SF-36v2 appears to be a psychometrically sound tool for the assessment of health-related quality of life of Dutch patients with RA.

Distinct Trajectories of Disease Activity Over the First Year in Early Rheumatoid Arthritis Patients Following a Treat-to-Target Strategy

Although treat‐to‐target (T2T) strategies are effective in early rheumatoid arthritis (RA) patients, important individual variations exist in the course toward remission. Growth mixture modeling provides more insight into this heterogeneity by identifying subgroups of patients with similar response patterns. This study aimed to identify distinct trajectories of disease activity in early RA patients following a T2T strategy during their first year.

Extending the floor and the ceiling for assessment of physical function

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”]).

Predictors of satisfactory improvements in pain for patients with early rheumatoid arthritis in a treat-to-target study

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 multivariable logistic regression analyses were used to identify significant predictors of achieving an absolute improvement of 30 mm or a relative improvement of 50% on a visual analogue scale for pain. RESULTS At 6 months, 125 of 209 patients (59.8%) achieved an absolute PPSI and 130 patients (62.2%) achieved a relative PPSI in pain. Controlling for baseline pain, having symmetrical arthritis was the strongest independent predictor of achieving an absolute [odds ratio (OR) 3.17, P = 0.03] or relative (OR 3.44, P = 0.01) PPSI. Additionally, anti-CCP positivity (OR 2.04, P = 0.04) and having ≤12 tender joints (OR 0.29, P = 0.01) were predictive of achieving a relative PPSI. The total explained variance of baseline predictors was 30% for absolute and 18% for relative improvements, respectively. CONCLUSION Symmetrical joint involvement, anti-CCP positivity and fewer tender joints at baseline are prognostic signs for achieving satisfactory improvement in pain after 6 months of treat to target in patients with early RA.

Modern psychometrics applied in rheumatology–A systematic review

BackgroundAlthough 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 highlight new possibilities for the improvement of outcome assessment in rheumatic conditions. Therefore, this study systematically reviewed the application of IRT to patient-reported and clinical outcome measures in rheumatology.MethodsLiterature searches in PubMed, Scopus and Web of Science resulted in 99 original English-language articles which used some form of IRT-based analysis of patient-reported or clinical outcome data in patients with a rheumatic condition. Both general study information and IRT-specific information were assessed.ResultsMost studies used Rasch modeling for developing or evaluating new or existing patient-reported outcomes in rheumatoid arthritis or osteoarthritis patients. Outcomes of principle interest were physical functioning and quality of life. Since the last decade, IRT has also been applied to clinical measures more frequently. IRT was mostly used for evaluating model fit, unidimensionality and differential item functioning, the distribution of items and persons along the underlying scale, and reliability. Less frequently used IRT applications were the evaluation of local independence, the threshold ordering of items, and the measurement precision along the scale.ConclusionIRT applications have markedly increased within rheumatology over the past decades. To date, IRT has primarily been applied to patient-reported outcomes, however, applications to clinical measures are gaining interest. Useful IRT applications not yet widely used within rheumatology include the cross-calibration of instrument scores and the development of computerized adaptive tests which may reduce the measurement burden for both the patient and the clinician. Also, the measurement precision of outcome measures along the scale was only evaluated occasionally. Performed IRT analyses should be adequately explained, justified, and reported. A global consensus about uniform guidelines should be reached concerning the minimum number of assumptions which should be met and best ways of testing these assumptions, in order to stimulate the quality appraisal of performed IRT analyses.

Validating the 28-Tender Joint Count Using Item Response Theory

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 tested whether the discrimination and difficulty parameters of the joints properly reflected the known left-right symmetry of joint involvement. External validity was evaluated by correlations with other established measures of disease activity, including pain, disability, general health, erythrocyte sedimentation rate (ESR), and the 28-swollen joint count. Results. The TJC-28 showed a good fit with the 2-parameter logistic model, with no relevant differential item functioning across sex, age, and time and with excellent reliability. The 28 joints covered a reasonable range of disease activity, even though they were mainly targeted at patients with moderate or high disease activity levels. The joint parameters reflected the left-right symmetry of joint involvement for all pairs of joints except one. All disease activity measures, except ESR, were significantly correlated with the TJC-28. Most correlations were of the expected magnitude. Conclusion. The TJC-28 showed good internal and acceptable external construct validity for patients with early-stage RA. The IRT analyses did point to some potential limitations of the instrument, a major problem being its limited measurement range. Future research should examine whether instrument modifications might lead to a more robust assessment of disease activity in patients with RA.

Validity of summing painful joint sites to assess joint-pain comorbidity in hip or knee osteoarthritis.

BackgroundPrevious 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.MethodsA total of 401 patients with hip or knee OA completed questionnaires on demographic variables and joint-pain comorbidities. Rasch analysis was performed to evaluate whether a sum score of joint-pain comorbidities can be calculated.ResultsSelf-reported joint-pain comorbidities showed a good fit to the Rasch model and were not biased by gender, age, disease duration, BMI, or patient group. As a group, joint-pain comorbidities covered a reasonable range of severity levels, although the sum score had rather low reliability levels suggesting it cannot discriminate well among patients.ConclusionsJoint-pain comorbidities, in other than the primary affected joints, can be summed into a joint pain comorbidity score. Nevertheless, its use is discouraged for individual decision making purposes since its lacks discriminative power in patients with minimal or extreme joint pain.

Contribution of assessing forefoot joints in early rheumatoid arthritis patients: Insights from item response theory.

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.

Tackling wicked problems in infection prevention and control: a guideline for co-creation with stakeholders

BackgroundInfection prevention and control can be seen as a wicked public health problem as there is no consensus regarding problem definition and solution, multiple stakeholders with different needs and values are involved, and there is no clear end-point of the problem-solving process. Co-creation with stakeholders has been proposed as a suitable strategy to tackle wicked problems, yet little information and no clear step-by-step guide exist on how to do this. The objectives of this study were to develop a guideline to assist developers in tackling wicked problems using co-creation with stakeholders, and to apply this guideline to practice with an example case in the field of infection prevention and control.MethodsA mixed-method approach consisting of the integration of both quantitative and qualitative research was used. Relevant stakeholders from the veterinary, human health, and public health sectors were identified using a literature scan, expert recommendations, and snowball sampling. The stakeholder salience approach was used to select key stakeholders based on 3 attributes: power, legitimacy, and urgency. Key values of stakeholders (N = 20) were derived by qualitative semi-structured interviews and quantitatively weighted and prioritized using an online survey.ResultsOur method showed that stakeholder identification and analysis are prerequisites for understanding the complex stakeholder network that characterizes wicked problems. A total of 73 stakeholders were identified of which 36 were selected as potential key stakeholders, and only one was seen as a definite stakeholder. In addition, deriving key stakeholder values is a necessity to gain insights into different problem definitions, solutions and needs stakeholders have regarding the wicked problem. Based on the methods used, we developed a step-by-step guideline for co-creation with stakeholders when tackling wicked problems.ConclusionsThe mixed-methods guideline presented here provides a systematic, transparent method to identify, analyze, and co-create with stakeholders, and to recognize and prioritize their values, problem definitions, and solutions in the context of wicked problems. This guideline consists of a general framework and although it was applied in an eHealth context, may be relevant outside of eHealth as well.

Exploring Fatigue Trajectories in Early Symptomatic Knee and Hip Osteoarthritis: 6-year Results from the CHECK Study

Objective. To examine whether different groups of fatigue trajectories can be identified among patients with early symptomatic osteoarthritis (OA) of the knee or hip, to describe the level of fatigue severity within each of these fatigue groups, and to investigate the involvement of age, sex, use of medication, comorbidity, and OA severity in relation to group membership. Methods. Six years of followup data on fatigue (Medical Outcomes Study Short Form-36 Vitality scale) came from the Cohort Hip and Cohort Knee (CHECK) cohort. Growth mixture modeling was applied to identify distinct fatigue trajectories as well as to take into account the effects of the patient characteristics. Results. Three fatigue trajectories were identified: low fatigue, low-to-high fatigue, and high fatigue. Latter trajectories showed considerable overlap from years 2 to 6, but differed in some patient characteristics in comparison with each other and in comparison with the low fatigue group. Comorbidity, medication use, and sex were significantly associated with the identified trajectories. Women, individuals with a comorbid disease, and those who used medication were more likely to follow a high fatigue trajectory. Conclusion. These findings suggest heterogeneous development of fatigue in the early OA population associated with varying patient characteristics. Further, this study shows that a considerable number of patients with OA already experience elevated levels of fatigue at an early stage of OA. While these findings need to be replicated, the identification of these trajectories with differing patient characteristics may warrant tailored psychosocial interventions for patients with elevated levels of fatigue.