Figures
- Fig. 1—
Flow chart showing the high-resolution computed tomography (HRCT) pattern in patients with rheumatoid arthritis-associated interstitial lung disease (RA-ILD). Of 99 patients with RA-ILD, 84 had HRCT scans available within 1 yr of initial presentation and enrolment into a longitudinal cohort. The HRCT pattern distribution is shown. The two cases with an alternative pattern (organising pneumonia (n = 1) and bronchiolitis (n = 1)) were excluded from the study analysis. NSIP: nonspecific interstitial pneumonia; UIP: usual interstitial pneumonia.
- Fig. 2—
Kaplan–Meier survival curve for patients with a rheumatoid arthritis (RA)-associated usual interstitial pneumonia (UIP) pattern (RA-UIP; ––––), a RA-associated non-UIP pattern (RA-non-UIP; ······) and idiopathic pulmonary fibrosis (IPF; ------). Comparing across all three groups, there were significant differences in survival estimates (p = 0.01). The estimated median survival in RA-UIP was significantly worse than that in RA-non-UIP (3.2 versus 6.6 yrs; p = 0.04). Estimated median survival in RA-UIP did not differ significantly from that in IPF (3.2 versus 2.6 yrs; p = 0.66).
- Fig. 3—
Kaplan–Meier survival curve for patients with rheumatoid arthritis-associated interstitial lung disease based on high-resolution computed tomography (HRCT) pattern. Comparing the three main HRCT patterns (–––––: definite usual interstitial pneumonia (UIP); -------: likely nonspecific interstitial pneumonia (NSIP); ······: indeterminate UIP/NSIP), there was a trend toward differences in survival estimates (p = 0.06). The estimated median survival in definite UIP was significantly worse than that in likely NSIP (3.2 yrs versus incalculable; p = 0.02). The estimated median survival for an indeterminate UIP/NSIP pattern did not differ from that for definite UIP and likely NSIP (6.6 versus 3.2 yrs (p = 0.15) and 6.6 yrs versus incalculable (p = 0.19), respectively).
- Fig. 4—
Flow chart of histopathology and high-resolution computed tomography (HRCT) pattern in patients with rheumatoid arthritis-associated interstitial lung disease (RA-ILD). Histopathology was available for 18 of the RA-ILD patients. UIP: usual interstitial pneumonia; NSIP: nonspecific interstitial pneumonia; TBB: transbronchial biopsy; SLB: surgical lung biopsy; OP: organising pneumonia; DAD: diffuse alveolar damage.
- Fig. 5—
Medication use in rheumatoid arthritis-associated interstitial lung disease patients. Medication regimens from the time of the initial and last follow-up visit were reviewed. Prednisone was the most common agent prescribed, followed by methotrexate (MTX) and an anti-tumour necrosis factor (anti-TNF) agent.
Tables
- Table 1—
Demographic and clinical characteristics of rheumatoid arthritis-associated interstitial lung disease patients
Population p-value RA-UIP RA-non-UIP IPF Overall RA-non-UIP# IPF# Subjects n 20 62 51 Age yrs 69±6 65±10 72±9 0.001 0.15 0.08 Male sex 55 50 75 0.03 0.70 0.11 Duration of RA yrs 7 (3–30) 2 (0–9) NA NA 0.03 NA Ever-smoker 55 77 76 0.12 0.05 0.07 FVC % pred 66±25 70±20 69±21 0.72 0.39 0.63 DL,CO % pred 50±22 48±21 41±16 0.10 0.56 0.07 Data are presented as mean±sd, percentage or median (interquartile range), unless otherwise indicated. RA-UIP: usual interstitial pneumonia (UIP) pattern in patients with rheumatoid arthritis (RA); RA-non-UIP: non-UIP pattern in patients with RA; IPF: idiopathic pulmonary fibrosis; FVC: forced vital capacity; DL,CO: diffusing capacity of the lung for carbon monoxide; NA: not applicable; % pred: percentage of the predicted value. #: versus RA-UIP.
- Table 2—
Predictors of survival time in patients with rheumatoid arthritis-associated interstitial lung disease
Bivariate Multivariate Hazard ratio p-value Hazard ratio p-value Female sex 0.55 0.10 0.30 0.008 Baseline FVC (% pred) 0.98 0.01 Baseline DL,CO (% pred) 0.97 0.002 0.96 0.003 Definite UIP pattern# 2.09 0.04 2.34 0.05 Hazard ratios reflect the relative risk of death associated with the given variable (or, for continuous variables, a one-unit increase in the variable). FVC: forced vital capacity; DL,CO: diffusing capacity of the lung for carbon monoxide; UIP: usual interstitial pneumonia; % pred: percentage of the predicted value. #: on high-resolution computed tomography.
