Article type
Year
Abstract
Background: systematic reviews on rare disorders are limited and imply particular methodological challenges due to the limited amount of primary studies, especially few randomized controlled trials (RCTs) or intervention studies, small sample sizes, and heterogeneity in methodologies, measurements and populations. The past decades have witnessed increased research activity on methodological and statistical issues related to rare disorders, but reviews that include an expedient grading of evidence are far ahead.
Objectives: to emphasize and discuss the particular challenges of doing reviews in rare disorders and present a method of mixed method systematic reviews (MMSR) in rare diseases.
Methods: we have conducted three MMSRs published in high-rated journals based on our method, and the fourth is in progress. MMSR of psychosocial aspects of Marfan syndrome (MFS) (including 15 primary studies with quantitative, qualitative and mixed–methods design), MMSR of chronic pain in MFS (including 20 primary studies with quantitative design) and MMSR of quality of life in people with hereditary thoracic aortic aneurysm and dissection diagnoses ((HTAAD) including 20 primary studies with quantitative design and one intervention study). Our method of MMSR is based on the PRISMA checklist for systematic reviews, including six specific validated criteria for critical appraisal of the included studies. In addition we included two assessment criteria, which we found important in the field of rare diseases. We also developed a method for analyzing and synthesizing the results of the included studies.
Results: in our three MMSRs we adjusted eligibility criteria to include all types of study design due to the small amount of research. We found no reviews or RCTs; we identified only one small pilot intervention study, the rest were cross-sectional. The studies were too heterogeneous to perform statistical pooling. We therefore performed a narrative synthesis of the findings, taking into account methodological quality and analytic rigour in the examination of the reported findings. We revealed that most studies included in our three MMSRs were of small sample sizes, had low response rates and/or participants without verified diagnoses. We provided possible explanations for the heterogeneity in methodology and populations and the discrepancy of results. We also identified research gaps on psychosocial aspects and chronic pain in people with MFS, and lack of research on quality of life in other HTAAD diagnoses than MFS.
Conclusions: MMSRs including critically assessment and synthesizing results of relevant studies are important for developing evidence-based clinical practice in the field of rare diseases. Using MMSRs as a method for systematic review in rare diseases may solve some of these challenges.
Patient or healthcare consumer involvement: knowledge users have been involved in the dissemination and implementation process.
Objectives: to emphasize and discuss the particular challenges of doing reviews in rare disorders and present a method of mixed method systematic reviews (MMSR) in rare diseases.
Methods: we have conducted three MMSRs published in high-rated journals based on our method, and the fourth is in progress. MMSR of psychosocial aspects of Marfan syndrome (MFS) (including 15 primary studies with quantitative, qualitative and mixed–methods design), MMSR of chronic pain in MFS (including 20 primary studies with quantitative design) and MMSR of quality of life in people with hereditary thoracic aortic aneurysm and dissection diagnoses ((HTAAD) including 20 primary studies with quantitative design and one intervention study). Our method of MMSR is based on the PRISMA checklist for systematic reviews, including six specific validated criteria for critical appraisal of the included studies. In addition we included two assessment criteria, which we found important in the field of rare diseases. We also developed a method for analyzing and synthesizing the results of the included studies.
Results: in our three MMSRs we adjusted eligibility criteria to include all types of study design due to the small amount of research. We found no reviews or RCTs; we identified only one small pilot intervention study, the rest were cross-sectional. The studies were too heterogeneous to perform statistical pooling. We therefore performed a narrative synthesis of the findings, taking into account methodological quality and analytic rigour in the examination of the reported findings. We revealed that most studies included in our three MMSRs were of small sample sizes, had low response rates and/or participants without verified diagnoses. We provided possible explanations for the heterogeneity in methodology and populations and the discrepancy of results. We also identified research gaps on psychosocial aspects and chronic pain in people with MFS, and lack of research on quality of life in other HTAAD diagnoses than MFS.
Conclusions: MMSRs including critically assessment and synthesizing results of relevant studies are important for developing evidence-based clinical practice in the field of rare diseases. Using MMSRs as a method for systematic review in rare diseases may solve some of these challenges.
Patient or healthcare consumer involvement: knowledge users have been involved in the dissemination and implementation process.
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