Is it still significant to denote the etiology of ILD in a patient with PPF?

Yes, absolutely! Infact, the most effective treatment in patients without IPF (PPF) is treatment of the cause. So if there is underlying autoimmune disease or exposure, primary treatment should be directed against that trigger and this has potential to stop progression and even improve lung function...

I agree with @Dr. First Last: We rheumatologists need to understand (and teach others) that systemic autoimmune diseases can present with manifestations other than those that we most identify with that of SARD.

For example, this is particularly true with Sjogren's disease. If we only measure ANA/SSA/...

I don’t have a great answer for this. I screen nearly every new ILD patient with ENA screen, myositis panel, RA, scleroderma, and Sjogren’s. But I’ve got to say this feels like a “thing we/I do for no reason.”

Honest question: what is the hit rate for indiscriminate screening for CTD in this populat...

ILD caused by an autoimmune process may precede other clinical manifestations of autoimmune disease. Knowing if or which serologies are positive can guide the most appropriate and earliest interventions and monitoring.

The longer amount of time I have spent in this space in collaboration with pulmonolgists in CTD-ILD clinics at two institutions now, I am firmly in the camps of Drs. @Dr. First Last and @Dr. First Last. Not sure pan-serologic profiling is productive for the patient coming in with pulmonary fibrosis ...