Associations with, and predictors of, progression in systemic sclerosis-related interstitial lung disease: a scoping literature review.

backgroundProgressive systemic sclerosis-related interstitial lung disease (SSc-ILD) is a leading cause of morbidity and mortality in systemic sclerosis (Ssc). Yet, there remains no consensus definition of interstitial lung disease (ILD) progression or risk stratification tool to aid in identifying for whom and when therapeutic intervention is warranted or which patients should be included in clinical trials because they are especially at risk of progressive disease.

objectiveWe aimed to determine from the literature which variables were consistently associated with SSc-ILD and, more importantly, which have been demonstrated to be predictors of progression.

methodsWe used two electronic databases, EMBASE and PubMed, to perform a scoping literature review of published articles on SSc-ILD, with a primary focus on ILD progression. Any variables reported to be associated with or predictive of ILD progression were recorded.

resultsOf the 1327 citations identified, 56 full-text articles were included in this scoping review. Most studies assessed the association of baseline variables with ILD progression and were not true assessments of the predictive value of these variables. In fact, analysis of the literature revealed a lack of a clear consensus definition for ILD progression. As such, there is a paucity of variables that can predict with confidence which patients will show ILD progression. Only one variable, the serological biomarker KL-6, was found to be consistently predictive of progression.

conclusionsSignificant knowledge gaps remain in our ability to predict individuals at risk of progressive SSc-ILD. Given the significant morbidity and mortality associated with progressive ILD, identifying these patients and their successful enrolment in clinical therapeutic trials is of the upmost importance.