Dynamic prediction of pulmonary hypertension in systemic sclerosis using landmark analysis

OBJECTIVE: Pulmonary hypertension (PH) is a serious complication of systemic sclerosis (SSc). We explore prediction of short-term risk for PH using serial pulmonary function tests (PFTs) and other disease features. METHODS: Subjects with SSc, disease onset≥10 years prior to data retrieval, available autoantibody specificity and PFTs were included. Mixed effects modelling was used to describe change in PFTs over time. Landmarking was utilized to include serial assessments and stratified Cox proportional hazards regression analysis with landmarks as strata was used to develop the PH prediction models. RESULTS: We analysed 1247 SSc patients, 16.3% male, 35.8% with dcSSc. Anticentromere, anti-topoisomerase and anti-RNA polymerase antibodies were observed in 29.8%, 22.0% and 11.4% respectively and PH developed in 13.6%. Over time diffusing capacity for carbon monoxide (DLco) and carbon monoxide transfer coefficient (Kco) declined in all SSc patients (up to 1.5%/year) but demonstrated much greater annual decline (up to 4.5% and 4.8% respectively) in the 5-7 years preceding PH diagnosis. Comparison between multivariable models including either DLco, Kco or FVC/DLco ratio, demonstrated that both absolute values and change over preceding year in those measurements associate strongly with risk of PH (HR 0.93 and 0.76 for Kco and its change; HR 0.90 and 0.96 for DLco and its change; and HR 1.08 and 2.01 for FVC/DLco ratio and its change; p<0.001 for all). The Kco based model had the greatest discriminating ability (Harrell's C 0.903). CONCLUSION: Our findings strongly support the importance of PFT trends over time in identifying patients at risk of PH. This article is protected by copyright. All rights reserved

Prognostic and predictive markers of systemic sclerosis-interstitial lung disease in a clinical trial and long-term observational cohort

OBJECTIVES: Explore prognostic and predictive markers of systemic sclerosis-associated interstitial lung disease (SSc-ILD) outcomes in a phase 3 trial (focuSSced) and prognostic markers in a real-world cohort (SMART). METHODS: The focuSSced SSc-ILD subgroup included 68 of 106 placebo-treated and 68 of 104 tocilizumab-treated patients. The SMART cohort included 505 patients with SSc-ILD. Linear mixed-effect models were used to identify factors associated with change in forced vital capacity (FVC). Kaplan-Meier estimation and Cox regression were used for time-to-event analyses. RESULTS: In placebo-treated focuSSced patients, sex was a significant prognostic factor for FVC decline; males had increased risk for absolute decline ≥10% in percent-predicted FVC (ppFVC) and 0.22% faster weekly FVC decline than females (P = 0.0001). FVC was 9.8% lower in patients with C-reactive protein >6 mg/ml versus those with C-reactive protein ≤6 mg/ml (P = 0.0059). Tocilizumab reduced the risk for ≥10% decline in ppFVC in patients who were male, had earlier disease (<2 years duration), had interleukin-6 levels <10 pg/ml, or had anti-topoisomerase antibodies (ATA). In the SMART cohort, prognostic factors for ppFVC <70% were male sex, ATA, and low baseline FVC. Males had 3.3% lower FVC 1 year after disease onset (P < 0.001) and 0.6% faster yearly decline (P = 0.03) than females. CONCLUSION: Prognostic markers in SSc-ILD were similar between focuSSced and SMART. Male sex and inflammatory markers were associated with lower FVC but interleukin-6 ≥ 10 pg/ml was not predictive of response to tocilizumab. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02453256

Prediction of Pulmonary Complications and Long-Term Survival in Systemic Sclerosis

Objective. To assess survival and incidence of organ-based complications in a large single-center cohort of unselected systemic sclerosis (SSc) patients, and to explore predictors of survival and clinically significant pulmonary fibrosis (PF) and pulmonary hypertension (PH). Methods. The study cohort consisted of 398 consecutive SSc patients, followed up for up to 15 years. Cox proportional hazards analysis with demographic, clinical, and laboratory characteristics as predictor variables was used to develop prediction models for pulmonary complications and survival. Results. The overall survival estimate at the end of followup was 57% among patients with limited cutaneous SSc (lcSSc) and 50% among patients with diffuse cutaneous SSc (dcSSc) (P = 0.017). We found that greater age at disease onset, dcSSc, lower diffusing capacity for carbon monoxide (DLCO), lower hemoglobin levels, higher serum creatinine levels, and the presence of PH or cardiac involvement were independent predictors of worse survival. Over the entire followup period, 42% of dcSSc patients and 22% of lcSSc patients developed clinically significant PF (P < 0.001). The variables that predicted clinically significant PF development were dcSSc, greater age at onset, lower forced vital capacity and DLCO, and the presence of anti-topoisomerase I antibody, while the presence of anticentromere antibody was protective. There was no difference in cumulative incidence of PH between the 2 subsets-24% in lcSSc and 18% in dcSSc (P = 0.558). Incidence rates were 1-2% per year. The PH prediction model demonstrated that greater age at onset, increase in serum creatinine levels, lower DLCO, and the presence of anti-RNA polymerase III or anti-U3 RNP antibodies were associated with increased risk of PH, while anti-topoisomerase I antibody positivity reduced the hazard. Conclusion. Our study provides data on long-term outcome of SSc and the timing and frequency of major organ complications. The predictive models we present could be used as clinical tools for patient risk stratification and could facilitate cohort enrichment for event-driven studies