Characteristics and risk factors of interstitial pneumonia with autoimmune features

BACKGROUND

Interstitial pneumonia with autoimmune features (IPAF) has features of connective tissue disease-associated interstitial lung disease (CTD-ILD), but without meeting criteria for a specific CTD. We compared baseline characteristics, survival, and response to treatment of IPAF to both CTD-ILD and unclassifiable ILD.

METHODS

Measurements were extracted from a prospective registry. Baseline features and survival were compared in IPAF against both CTD-ILD and unclassifiable ILD. Linear trajectory of lung function decline (%-predicted forced vital capacity [FVC%] and diffusion capacity of the lung for carbon monoxide [DLCO%]) before and after initiation of mycophenolate or azathioprine were compared in IPAF against both CTD-ILD and unclassifiable ILD using linear mixed models.

RESULTS

Compared to CTD-ILD (n = 1240), patients with IPAF (n = 128) were older, more frequently male, and had greater smoking history. Compared to unclassifiable ILD (n = 665), patients with IPAF were younger, more frequently female, and had worse baseline lung function. IPAF had higher mortality compared to CTD-ILD and similar risk of mortality compared to unclassifiable ILD. Mycophenolate initiation was associated with stabilization of FVC% and DLCO% in all ILD subtypes except for FVC% in patients with IPAF, and azathioprine initiation with stabilization of FVC% and DLCO% in all ILD subtypes except for FVC% decline in IPAF and DLCO% decline in CTD-ILD.

CONCLUSION

Patients with IPAF had worse survival compared to those with CTD-ILD and similar mortality to unclassifiable ILD, with treatment being associated with stabilization in lung function in all three ILDs. It is uncertain whether IPAF should be considered a distinct ILD diagnostic subgroup.

Connective tissue disease-associated interstitial lung disease and outcomes after hospitalization: A cohort study

BACKGROUND

The impact of hospitalization on patient outcomes is increasingly recognized and considered in the prognostication of many pulmonary disorders. We sought to evaluate the impact of hospitalization on survival in connective tissue disease-interstitial lung disease (CTD-ILD) patients.

METHODS

A chart review of patients with CTD-ILD followed at a tertiary care center was performed. Patients were stratified into two groups based on hospitalization status. Outcomes of the groups were compared using Kaplan-Meier survival analyses as well as multivariate competing risk analysis.

RESULTS

There were 137 patients identified with confirmed CTD-ILD. Patients who underwent hospitalization for any reason had a significant decrease in transplant-free survival compared to the never hospitalized cohort (3-year survival 60% vs. 94%; p = 0.0001). Hospitalization for ≥7 days was associated with worse outcomes than those hospitalized for <7 days (median survival 1.59 years vs. 7.17 years, p = 0.0012). Based on multivariate competing risk analysis, factors associated with death, with lung transplantation as a competing risk, were age (HR = 1.05 [95% 1.01-1.09]; P = 0.0443), male gender (HR = 4.94 [95% CI: 1.58-15.41]; P = 0.006), and all cause hospitalization (HR = 11.97 [95% CI: 1.36-105.49]; P = 0.0253).

CONCLUSION

This study highlights the impact of hospitalization on subsequent outcomes in the CTD-ILD population with a significantly reduced transplant-free survival demonstrated, especially after cardiopulmonary hospitalization events.