Treatment of systemic sclerosis-associated interstitial lung disease: A systematic literature review and meta-analysis

ABSTRACT Background: Systemic sclerosis (SSc) is an immune-mediated disease characterized by small vessel vasculopathy and fibroblast dysfunction that leads to increased production of extracellular matrix. Interstitial lung disease represents one of the most common complications, by affecting almost 70% of patients with SSc. Objective: To evaluate the effectiveness of the pharmacological treatments available for systemic sclerosis-associated interstitial lung disease (SSc-ILD) based on pulmonary function tests and radiologic findings. Materials and methods: A systematic literature review and meta-analysis were conducted. A thorough literature search was made in EMBASE, PUBMED, and Cochrane CENTRAL to collect studies published between January 2015 and July 31 of 2019. The primary outcomes were forced vital capacity (FVC), diffusion capacity of carbon monoxide (DLCO), and high-resolution computed tomography findings (HR-CT). Studies using medications for the treatment of SSc-ILD including cyclophosphamide (CYC), mycophenolate mofetil (MMF), nintedanib, pirfenidone, or rituximab (RTX) were included. Effect measures were calculated based on available data, and a meta-analysis was made with these results. Results: We found a total of 312 studies. 49 studies were selected for full-text assessment after reading the abstracts. Finally, 14 studies were selected to be included in the final review. 2 meta-analyses, 8 clinical trials, 3 retrospective cohorts, and one nested case-control study were identified. The available evidence supports the use of CYC and MMF as the best options for the treatment of SSc-ILD, with MMF being the preferred option based on a better safety profile. Other medications such as RTX, pirfenidone, and nintedanib show potential as alternatives to CYC. The overall quality of evidence available is adequate based on generally well-designed studies. Meta-analysis was done by assessing >5% or >10% decrease of FVC when comparing pharmacological agents vs. placebo. Results show that the use of pharmacological agents is negatively associated with the worsening of FVC. However, high heterogeneity limits the number of studies used during quantitative analysis, affecting the overall results. Conclusions: Immunosuppressive therapies remain as the cornerstone of treatment of SSc-ILD, as most evidence show improvement or slow progression of pulmonary function tests by using them, especially CYC and MMF. However, more evidence is required regarding the use