{
  "abstract": "Introduction Systemic sclerosis (SSc) is a rare autoimmune disease in which pulmonary involvement is the major cause of death. Despite its importance, the natural history of lung function in immunosuppressive treatment-naïve SSc patients remains incompletely understood. We sought to investigate longitudinal FVC trajectories in a well-defined SSc cohort and identify baseline characteristics predicting poor trajectory.Material and Methods A total of 299 SSc patients, who were diagnosed according to 2013 EULAR/ACR classification criteria, were enrolled into this single-center prospective observational cohort study between January 2015 and June 2024. After obtaining baseline characteristics, serial pulmonary function tests were collected annually. Trajectory of FVC percent predicted was analyzed among those who had been naive to any immunosuppressants at baseline until the initiation of immunosuppressive therapy, lung surgery, transplantation, or death. Trajectory was modeled using latent class mixed-effects methods to derive trajectory subgroups. Each patient’s posterior probability of membership in one of three latent classes was calculated, and patients were assigned to the subgroup with the highest probability. Group comparisons were performed using the Kruskal–Wallis test for continuous variables and the exact chi-square test for categorical variables. Baseline demographic, clinical, serologic, and echocardiographic features were compared across trajectory classes.Results A total of 148 patients were eligible and followed for a mean of 6.5 years. The cohort was predominantly female (89.9%) with a mean age of 56 years, and 48% had interstitial lung disease (ILD) at baseline. Three distinct FVC trajectories were identified ( figure 1). A minority of patients (Class 1, n=9) demonstrated a continuous decline in FVC. A second group (Class 2, n=57) consistently maintained the highest FVC values over time, while the largest group (Class 3, n=82) showed stability at intermediate FVC levels. Patients in the declining trajectory were more likely to present with ILD, anti-Scl-70 antibody positivity, and reduced six-minute walk test distance. In contrast, those in Class 2 had more favorable baseline physiology and preserved FVC, whereas patients in Class 3 displayed intermediate features (table 1).Conclusions Immunosuppressive treatment-naïve SSc patients can be categorized into declining, improving, and stable patterns in long-term FVC trajectories. Baseline presence of ILD, six-minute walk test performance, and anti-Scl-70 antibody positivity were predictive of subsequent decline. These findings highlight heterogeneity in the natural course of SSc-associated lung disease and suggest that trajectory-based classification may provide a clinically meaningful framework for identifying patients at risk of progression who warrant closer surveillance and earlier intervention.Abstract P.418 Figure 1Predieted trajeetories of forced vital capacity (FVC) in systemic selerosisAbstract P.418 Table 1Baseline characteristies of systemic sclerosis patients across FVC trajectory subgroups",
  "authors": [
    {
      "affiliations": [
        "Division of Rheumatology, Department of Internal Medicine, Seoul National University Hospital, Seoul, South Korea"
      ],
      "name": "Hee Won Cho"
    },
    {
      "affiliations": [
        "Division of Rheumatology, Department of Internal Medicine, Seoul National University Hospital, Seoul, South Korea"
      ],
      "name": "Eun Bong Lee"
    },
    {
      "affiliations": [
        "Division of Rheumatology, Department of Internal Medicine, Seoul National University Hospital, Seoul, South Korea"
      ],
      "name": "Jun Won Park"
    },
    {
      "affiliations": [
        "Division of Rheumatology, Department of Internal Medicine, Seoul National University Hospital, Seoul, South Korea"
      ],
      "name": "Jin Kyun Park"
    },
    {
      "affiliations": [
        "Medical Research Collaborating Center, Seoul National University Hospital, Seoul, South korea"
      ],
      "name": "Yunhee Choi"
    }
  ],
  "title": "P.418 Forced vital capacity trajectories in treatment-naïve systemic sclerosis: a 10-year prospective cohort study",
  "uid": "d196cb4c-f989-5612-8ab2-12bf85eafa35"
}