Objective: To assess if an integrated longitudinal analysis using all available imaging data affects the precision of estimates of change in patients with axial spondyloarthritis (axSpA), with... Show moreObjective: To assess if an integrated longitudinal analysis using all available imaging data affects the precision of estimates of change in patients with axial spondyloarthritis (axSpA), with completers analysis as reference standard.Methods: Patients from the DESIR cohort fulfilling the ASAS axSpA criteria were included. Radiographs and MRIs of the sacroiliac joints and spine were obtained at baseline, 1, 2 and 5 years. Each image was scored by 2 or 3 readers in 3 'reading-waves' (or campaigns). Each outcome was analyzed: i. According to a 'combination algorithm' (e.g. '2 out of 30 for binary scores); and ii. Per reader. Change over time was analyzed with generalized estimating equations by 3 approaches: (a)'integrated-analysis' (all patients with >1 score from >1 reader from all waves); (b1)Completers-only analysis (patients with 5-year follow-up, using scores from individual readers); (b2)Completers analysis using a 'combination algorithm' (as (b1) but with combined scores). Approaches (b1) and (b2) were considered the 'reference'.Results: In total, 413 patients were included. The 'integrated analysis' was more inclusive with similar levels of precision of the change estimates as compared to both completers analyses. In fact, for low-incident outcomes (e.g.% mNY-positive over 5-years), an increased incidence was 'captured', with more precision, by the 'integrated analysis' compared to the completers analysis with combined scores (% change/year (95%CI): 1.1 (0.7; 1.5) vs 1.2 (0.5; 1.8), respectively).Conclusion: An efficient and entirely assumption-free 'integrated analysis' does not jeopardize precision of the estimates of change in imaging parameters and may yield increased statistical power for detecting changes with low incidence. (C) 2020 The Authors. Published by Elsevier Inc. Show less
In this thesis we have pursued innovative analytical solutions for some of the most challenging questions in the field of SpA. We have gained better insights into the concept of axSpA by studying... Show moreIn this thesis we have pursued innovative analytical solutions for some of the most challenging questions in the field of SpA. We have gained better insights into the concept of axSpA by studying it independently of the rheumatologist’s opinion. Our findings likely add knowledge to what axSpA really is. Future studies will learn us how much of these insights will translate into a better recognition of the disease in clinical practice and in better classifying them for research purposes. Since SpA is a slowly progressing disease, several years are needed to see meaningful changes in imaging abnormalities of the axial skeleton, which poses methodological challenges. We have shown that thoughtful analytical approaches, that make best use of imaging data, are helpful in better estimating progression, in unravelling its determinants and in clarify which outcomes are best to monitor disease. Efforts are made to further improve outcome measurement in axSpA, including the development of new imaging techniques, which can benefit from our proposed solutions to long-term imaging scoring. Show less
Objective: Article full texts are often inaccessible via the standard search engines of biomedical literature, such as PubMed and Embase, which are commonly used for systematic reviews. Excluding... Show moreObjective: Article full texts are often inaccessible via the standard search engines of biomedical literature, such as PubMed and Embase, which are commonly used for systematic reviews. Excluding the full-text bodies from a literature search may result in a small or selective subset of articles being included in the review because of the limited information that is available in only title, abstract, and keywords. This article describes a comparison of search strategies based on a systematic literature review of all articles published in 5 topranked epidemiology journals between 2000 and 2017. Study Design and Setting: Based on a text-mining approach, we studied how nine different methodological topics were mentioned across text fields (title, abstract, keywords, and text body). The following methodological topics were studied: propensity score methods, inverse probability weighting, marginal structural modeling, multiple imputation, Kaplan-Meier estimation, number needed to treat, measurement error, randomized controlled trial, and latent class analysis. Results: In total, 31,641 Hypertext Markup Language (HTML) files were downloaded from the journals' websites. For all methodological topics and journals, at most 50% of articles with a mention of a topic in the text body also mentioned the topic in the title, abstract, or keywords. For several topics, a gradual decrease over calendar time was observed of reporting in the title, abstract, or keywords. Conclusion: Literature searches based on title, abstract, and keywords alone may not be sufficiently sensitive for studies of epidemiological research practice. This study also illustrates the potential value of full-text literature searches, provided there is accessibility of fulltext bodies for literature searches. (C) 2020 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Show less
