{
  "abstract": "Introduction Mixed connective tissue disease (MCTD) shares overlapping features with systemic sclerosis (SSc) and idiopathic inflammatory myopathies (IIM) with a proportion of patients presenting with interstitial lung disease (ILD). However, there are limited comparative data regarding ILD severity, progression patterns, and outcomes between each of these entities.We aim to compare the severity of lung involvement in patients with MCTD- ILD versus those with SSc- ILD and IIM-ILD.Material and Methods We retrospectively included patients diagnosed with MCTD, SSc, IIM and associated ILD on chest computed tomography (CT) scans with a follow-up of 4 years (±12 months). All patients with MCTD-ILD (n=13) were matched with SSc-ILD and IIM-ILD in a 1:1:1 ratio based on age and disease duration. The primary outcome was the proportion of patients with at least one period of ILD progression, defined as an annual >10% relative decline in forced vital capacity (FVC). Secondary analyses included annual assessments of FVC, diffusing capacity of carbon monoxide (DLCO) and mortality.Results Thirty-nine patients were included, with 33 (84.6%) being female. Mean age at ILD diagnosis was 47.6 ± 2.6 years and median time from initial disease diagnosis to ILD diagnosis was 12 months (IQR 30). Most patients (n=28, 72%) exhibited a non-specific interstitial pneumonia pattern. However, SSc-ILD patients presented significantly more frequently with usual interstitial pneumonia than MCTD-ILD patients (n=4, 30.8% vs. n=0, 0%, p<0.007). The extent of ILD on CT scan was not significantly different between groups. During the follow-up period, SSc-ILD patients showed a higher proportion of individuals with at least one annual >10% relative decline in FVC, approaching statistical significance (n=0 vs. n=5, p=0.054) when compared to MCTD-ILD patients. Conversely, IIM-ILD patients were more likely to experience a relative decline in FVC of >10% (p=0.026) within the first year of follow-up when compared with MCTD-ILD patients. At 3 years of follow-up, the mean relative decline in DLCO was significantly greater in SSc-ILD patients when compared to MCTD-ILD patients (mean difference of 24.7%, p<0.001). No other significant differences were found between groups in FVC or DLCO decline at annual follow-up assessments. No deaths were recorded during follow-up.Conclusions MCTD-ILD apparently has a more favorable clinical presentation than SSc-ILD or IIM- ILD. IIM-ILD and SSc-ILD demonstrated a more rapid decline in pulmonary function, particularly in the first years of follow-up. These findings highlight distinct ILD progression and underscore the importance of disease-specific monitoring strategies. However, larger, prospective studies are needed to confirm these observations.",
  "authors": [
    {
      "affiliations": [
        "Serviço de Reumatologia, Unidade Local de Saúde Santa Maria, Centro Académico de Medicina de Lisboa, Lisboa, Portugal"
      ],
      "name": "Filipa Costa"
    },
    {
      "affiliations": [
        "Serviço de Reumatologia, Unidade Local de Saúde Santa Maria, Centro Académico de Medicina de Lisboa, Lisboa, Portugal",
        "Faculdade de Medicina, Universidade de Lisboa, Centro Académico de Medicina de Lisboa., Lisboa, Portugal"
      ],
      "name": "Inês Sopa"
    },
    {
      "affiliations": [
        "Faculdade de Medicina, Universidade de Lisboa, Centro Académico de Medicina de Lisboa., Lisboa, Portugal"
      ],
      "name": "Khea Hasmucrai"
    },
    {
      "affiliations": [
        "CUF, Clínica do Barreiro, Barreiro, Portugal"
      ],
      "name": "Manuel Silvério-António"
    },
    {
      "affiliations": [
        "Unidade de Reumatologia, Unidade Local de Saúde de São José, Lisboa, Portugal"
      ],
      "name": "Ana Teresa Melo"
    },
    {
      "affiliations": [
        "Serviço de Reumatologia, Unidade Local de Saúde Santa Maria, Centro Académico de Medicina de Lisboa, Lisboa, Portugal",
        "Faculdade de Medicina, Universidade de Lisboa, Centro Académico de Medicina de Lisboa., Lisboa, Portugal"
      ],
      "name": "Joana Martinho"
    },
    {
      "affiliations": [
        "Serviço de Reumatologia, Unidade Local de Saúde Santa Maria, Centro Académico de Medicina de Lisboa, Lisboa, Portugal",
        "Faculdade de Medicina, Universidade de Lisboa, Centro Académico de Medicina de Lisboa., Lisboa, Portugal"
      ],
      "name": "Bianca Paulo Correia"
    },
    {
      "affiliations": [
        "Serviço de Reumatologia, Unidade Local de Saúde Santa Maria, Centro Académico de Medicina de Lisboa, Lisboa, Portugal",
        "Faculdade de Medicina, Universidade de Lisboa, Centro Académico de Medicina de Lisboa., Lisboa, Portugal"
      ],
      "name": "Nikita Khmelinskii"
    },
    {
      "affiliations": [
        "Serviço de Reumatologia, Unidade Local de Saúde Santa Maria, Centro Académico de Medicina de Lisboa, Lisboa, Portugal",
        "Faculdade de Medicina, Universidade de Lisboa, Centro Académico de Medicina de Lisboa., Lisboa, Portugal"
      ],
      "name": "Catarina Resende"
    },
    {
      "affiliations": [
        "Serviço de Reumatologia, Unidade Local de Saúde Santa Maria, Centro Académico de Medicina de Lisboa, Lisboa, Portugal",
        "Faculdade de Medicina, Universidade de Lisboa, Centro Académico de Medicina de Lisboa., Lisboa, Portugal"
      ],
      "name": "Raquel Campanilho-Marques"
    },
    {
      "affiliations": [
        "Serviço de Reumatologia, Unidade Local de Saúde Santa Maria, Centro Académico de Medicina de Lisboa, Lisboa, Portugal",
        "Faculdade de Medicina, Universidade de Lisboa, Centro Académico de Medicina de Lisboa., Lisboa, Portugal"
      ],
      "name": "Gonçalo Boleto"
    }
  ],
  "title": "P.115 Interstitial lung disease in mixed connective tissue disease: a distinct clinical pattern compared to systemic sclerosis and myositis",
  "uid": "bbec17e1-7737-5145-b461-86455ba77cb8"
}