Clinical, Functional, and Prognostic Evaluation of Idiopathic Pulmonary Fibrosis, Connective Tissue Disease-Associated Interstitial Lung Disease, Interstitial Pneumonia with Autoimmune Features: A Single-Center Prospective Study

Abstract

Objective: Our study aimed to evaluate clinical, functional, and prognostic features and to determine the prognosis of idiopathic pulmonary fibrosis, connective tissue disease-associated interstitial lung diseases, and interstitial pneumonia with autoimmune features.

Material and methods: Sixty-nine cases with interstitial lung diseases were recruited in this study prospectively. Demographic features, symptoms, radiological findings, functional measurements, and immunological markers were recorded twice (at the time of initial admission and in the 12th month). Twenty-four of 69 cases were idiopathic pulmonary fibrosis, 32 were connective tissue diseaseassociated interstitial lung diseases, and 13 were interstitial pneumonia with autoimmune features .

Results: Most of the patients with idiopathic pulmonary fibrosis were male, while there were more female patients in connective tissue disease-associated interstitial lung diseases and interstitial pneumonia with autoimmune features groups. Female patients (65.0%) predominated in connective tissue disease-associated interstitial lung diseases group (P <.001). There was no significant difference in the mean ages of the disease groups, yet connective tissue disease-associated interstitial lung diseases patients were generally younger (min- max: 34-82 years). In the idiopathic pulmonary fibrosis group, only low titers of antinuclear antibody positivity were found. Antinuclear antibody positivity in the connective tissue disease-associated interstitial lung diseases group and interstitial pneumonia with autoimmune features group was high (P = .001). The long-term survival of idiopathic pulmonary fibrosis, connective tissue disease-associated interstitial lung diseases, and interstitial pneumonia with autoimmune features patients were 37%, 40 months (median) (95% CI, 5.193- 74.807), 48.6%, 80 months (median) (95% CI, 57.032-102.968), 30.8%, 46 months (median) (95% CI, 26.624-65.376), respectively.

Conclusion: Although a consensus report describing interstitial lung diseases with autoimmune features has been published, diagnostic criteria for this group are still vague. Since the interstitial pneumonia with autoimmune features group had the worst results in terms of functional loss and survival rates, the follow-up parameters and follow-up algorithm should be established for this group. Clinical and immunological evaluation of the interstitial pneumonia with autoimmune features group should include detailed parameters because of follow-up and to estimate survival.

Figure 1.

Flowchart of patients.

Figure 2.

Total survival curves of patients with IPF, CTD-associated ILD, and IPAF groups. Kaplan–Meier survival comparison between IPF, CTD-associated ILD, and IPAF at long term (log-rank, P = 0.22) (small dash: IPF, medium dash: CTD-associated ILD, solid line: IPAF). IPF, idiopathic pulmonary fibrosis; CTD-associated ILD, connective tissue disease-associated interstitial lung disease; IPAF, interstitial pneumonia with autoimmune feature.