Rheumatoid arthritis-associated interstitial lung disease: epidemiology, risk/prognostic factors, and treatment landscape.

OBJECTIVES: To summarise the epidemiology, risk and prognostic factors, and treatment landscape of rheumatoid arthritis-associated interstitial lung disease (RA-ILD).

METHODS: Targeted and systematic literature reviews were conducted to characterise the epidemiology and treatment landscape associated with RA-ILD, respectively. MEDLINE®, Embase, and CENTRAL were searched via OvidSP in March 2019 and December 2018. The results were narratively summarised.

RESULTS: A total of 24 and 20 publications were captured through targeted and systematic literature review, respectively. No randomised controlled trials were identified; publications were observational cohort studies, cross-sectional, or case-control. Unadjusted incidence of interstitial lung disease (ILD) ranged from 1.3/1,000 person-years for interstitial pneumonia-type ILD to 5.0/1,000 person-years for 'probable or definite ILD'. Prevalence of ILD ranged from 1.8% to 67% (median: 24.9%) and varied with case definition and sample size. Few publications identified the same risk and prognostic factors; age, male sex, duration of disease, and antibodies to cyclic citrullinated peptides were the most frequently reported risk factors for development of RA-ILD, and age was the most common predictor of mortality. Despite identification of a variety of pharmacotherapeutic interventions, assessment of the comparative efficacy and safety of the available treatments were difficult due to heterogenous reporting of outcomes and small sample size.

CONCLUSIONS: A wide range of estimates were identified for incidence and prevalence of RA-ILD. Further, there was no consensus on risk and prognostic factors. Sufficiently powered clinical trials are needed to confirm the findings of the observational studies with respect to efficacy and safety of current treatments.