BACKGROUND AND OBJECTIVES

In SSc, ILD is a major cause of morbidity and mortality. We aimed to investigate the performance of DLCO (diffusing capacity of lung carbon monoxide) and FVC (forced vital capacity) delta change (Δ) and baseline values in predicting the development of SSc-ILD.

METHODS

Longitudinal data of DLCO, FVC, and ILD on the HRCT of SSc patients from the EUSTAR database were evaluated at baseline (t) and after 12 (±4) (t) and 24 (±4) (t) months.

RESULTS

474/17805 patients were eligible for the study (403 females); 46 (9.7%) developed ILD at t. Positivity for anti-topoisomerase antibodies (117 patients) showed an association with ILD development at t ( = 0.0031). Neither the mean t to t change (Δ) of DLCO nor the mean t to t FVCΔ predicted the appearance of ILD at t. Investigating the possible role of baseline DLCO and FVC values in predicting ILD appearance after 24 (±4) months, we observed a moderate predictive capability of t DLCO < 80%, stronger than that of FVC < 80%.

CONCLUSIONS

We suggest that an impaired baseline DLCO may be predictive of the appearance of ILD after 2 years of follow-up. This result advances the hypothesis that a reduction in gas exchange may be considered an early sign of lung involvement. However, further rigorous studies are warranted to understand the predictive role of DLCO evaluation in the course of SSc.