Ten Years of Interventional Research in Systemic Sclerosis: A Systematic Mapping of Trial Registries

Effects of socio-economic factors on research over systemic sclerosis: an analysis based on long time series of bibliometric data

Background

Systemic sclerosis (SSc) is a rare detrimental disease warranting global research efforts. Evaluating how socio-economic factors impact country research output on SSc could help to identify solutions advancing research.

Methods

Publication production on SSc during 1969–2018 and data for structural and policy factors for WHO member countries were collected from public sources. Associations between SSc research output and country-level factors were investigated through panel regression. Difference-in-differences analysis further assessed the causal effects of rare disease legislation.

Results

SSc publications demonstrated exponential growth (r = 0.9410, as against an r = 0.8845 after linear adjustment), but were concentrated in high-income countries (HICs). Ten countries, nine of which were HICs, published 12,261 (77.5%) SSc publications but another 87 countries produced none. Gross domestic products (GDP), population and expenditure on research and development were positively associated with SSc publications (p < 0.001). Higher health expenditure was only found to be associated with increased SSc publications in HICs (p < 0.001). Rare disease legislation increased annual publication production by 62.8% (95% CI 0.390–0.867; p < 0.001) averagely. In middle-income countries (MICs), the effect was especially swift and lasting. No significant impact was found with GDP per capita, female percentage, and political indicators.

Conclusions

SSc research output increased over time with substantial country disparities. Effective health policies facilitating research should be expanded especially among MICs to accelerate research advancement.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-021-02149-w.

Representativeness of Systemic Sclerosis Patients in Interventional Randomized Trials: an analysis of the EUSTAR database

OBJECTIVE

To estimate the extent of and the reasons for ineligibility in randomized controlled trials (RCTs) of systemic sclerosis (SSc) patients included in the EUSTAR database, and to determine the association between patient's features and generalizability of study results.

METHODS

We searched Clinicaltrials.gov for all records on interventional SSc-RCTs registered from January 2013 to January 2018. Two reviewers selected studies, and information on the main trial features were retrieved. Data from 8046 patients having a visit in the EUSTAR database since 2013 were used to check patient's eligibility. The proportion of potentially eligible patients per trial, and the risk factors for ineligibility were analyzed. Complete-, worst- and best-case analyses were performed.

RESULTS

Of the 37 RCTs included, 43% were conducted in Europe, 35% were industry-funded, and 87% investigated pharmacological treatments. Ninety-one percent of 8046 patients included could have participated in at least one RCT. In complete-case analysis, the median [range] proportion of eligible patients having the main organ complication targeted by each study was 60% [10-100] in the overall sample of trials, ranging from 50% [32-79] for trials on skin fibrosis to 90% [34-77] for those targeting Raynaud's phenomenon. Among the criteria checked, treatment- and safety-related but not demographic were the main barriers to patient's recruitment. Older age, absence of Raynaud's phenomenon, and lower mRSS were independently associated with the failure to fulfill criteria for any of the included studies.

CONCLUSIONS

Patient's representativeness in SSc-RCTs is highly variable and is driven more by treatment- and safety-related rather than demographic criteria.