Overview of redundant NMA of systemic treatment in plaque psoriasis
Creators: name: Guelimi, Robin
Publisher: name: Open Science Framework
Year: 2022
Subjects: subject: Dermatology
subject: Diseases
subject: Medicine and Health Sciences
subject: Medical Specialties
subject: Skin and Connective Tissue Diseases
subject: biotherapy
subject: network meta-analysis
subject: overview
subject: psoriasis
subject: systematic review
subject: systemic treatments

description: Psoriasis is a frequent chronic skin inflammatory disease that affects 1 to 8% of the general population. Physicians need to have a complete and up to date synthesis of the evidence concerning risk /benefit balance of available treatments to provide optimal care to patients. Considering the high and growing number of treatments available to treat moderate to severe psoriasis physician need to know which treatments work best and are better tolerated. However, among biologicals available for the treatment of psoriasis, a fair number of the molecules compared their efficacy versus placebo but head-to-head comparison of biologicals versus conventional or between them are rare. Network meta-analysis (NMA) is a relatively recently developed method that allows after a systematic review, the evaluation of several treatments in a single analysis. The number of systematic reviews (SR) and MAs published follows an exponential growth. The increase in number has been estimated at 2,728% between 1991 and 2014, and is greater than the growth of all the indexed publications. Meta-analyses are meant to be comprehensive synthesis of the literature and in some areas there are more meta-analyses of randomized trials than randomized trials . Specifically, in dermatology, in 2017 there were almost as many published meta-analyses as there were trials (ratio of 0.8). This abundance in publication follows the same growth as the number of redundant MA. A study showed that among a sample of 73 MAs published in 2010, there was at least one MA published on the same subject in 67% of cases, with a median of 2 MA and a maximum of 13 redundant MA. This phenomenon of redundant MAs exists for NMAs as well. In a sample of 88 NMAs, 77% had at least one redundant NMA, and the disease associated with the most redundant NMAs was rheumatoid arthritis with 28 NMAs published between 2003 and 2014. Furthermore, this study showed difference in results between redundant NMAs, both in the direction and in the effect size of the different treatments. The fact that the estimations of the effect of a treatment are different from one MA to the other is problematic since meta-analyses are supposed to be reproducible syntheses of the literature. It has been shown in the literature that MAs evaluating the same intervention could show different results in overall effect size estimate, but could also show different direction in overall effect size estimate. Those differences in results were shown to be, in some extent, due to different methodological choices. Recently, a proof-of-concept study was able to demonstrate in the context of a meta-analysis in indirect comparison that different combinations of methodological choices could lead to a large variability in the estimated overall effects, leading to totally contradictory results. Such variability in the results of MAs, if present, is a major flaw of the evidence-based medicine, that needs to be understood to propose adapted solutions. In the case of psoriasis, which is a chronic disease with severe and disabling effects, clear and reliable data on the effectiveness of the treatments offered to patients are essential. The objective of this study is to assess the number of redundant NMAs evaluating the efficacy and safety of systemic treatments in moderate to severe plaque psoriasis, to describe their characteristics, including their methodological choices, their results, and methodological quality and to compare the differences if present. Another objective will be to estimate the reproducibility of the results of NMA by reanalyzing a set of the most cited NMAs.