What if my lung-dominant connective tissue disease (LD-CTD) patient eventually met criteria for a definite CTD: The role of prognosis!

Objectives: Evaluate the characteristics of patients with lung-dominant connective tissue disease (LD-CTD) that eventually met criteria for a definite CTD. Methods: Patients with interstitial lung disease and positive antinuclear antibody results (≥1/320) and/or specific autoantibodies with at least one clinical extrathoracic feature suggesting a CTD were retrospectively evaluated. Results: Of the 1998 patients screened, 63 initially met the LD-CTD criteria. Eleven (18%) patients eventually met a definitive CTD criteria during follow-up [4 scleroderma(SSc), 3 polimyositis(PM), 3 Sjogren9s and 1 Rheumatoid Arthritis], after a median of 40 months, comprising the CTD group. Comparison between the CTD and the LD-CTD groups showed no statistically difference in age at diagnosis (53 vs 58 months), extrathoracic features of a CTD, autoantibody profile, ILD pattern (NSIP in 54% and 40%) or PFTs behavior over time. However, CTD group had a longer follow-up (median 84 vs. 52 months, p=0.003) and no death registered, opposed to 21% mortality rate in the LD-CTD group (p=0.09). Comparison between the deceased and survived groups showed significant differences in smoking (91% vs 42%, p=0.003) and follow-up length (median 58 vs 23 months, p= 0.0002). Conclusions: Our LD-CTD cohort showed a minority of patients who eventually met a definite CTD, mostly SSc, only after a long follow-up period. The persistent LD-CTD group had a shorter follow-up length and higher mortality with marginal statistical significance. No deaths were noticed in the CTD group, despite been followed more longer than the LD-CTD group, suggesting that LD-CTD might have a worse prognosis.