Interstitial lung disease in Egyptian patients with rheumatoid arthritis: Frequency, pattern and correlation with clinical manifestations and anti-citrullinated peptide antibodies level

Abstract

IntroductionInterstitial lung disease (ILD) represents 13% of the overall mortality in rheumatoid arthritis (RA) patients. Aim of the workTo determine the frequency and pattern of ILD among RA patients, correlate it with clinical manifestations and with anti-citrullinated peptide antibodies (ACPA) titer. Patients and methodsThis study included 88 RA patients. ILD was diagnosed by high-resolution computed tomography (HRCT) and assessed by a severity score. Disease activity was assessed by clinical disease activity index (CDAI) and functional status by the modified health assessment questionnaire (MHAQ). Serum ACPA titer was assayed by ELISA. ResultsThe mean age of the patients was 50.15±9 years, disease duration was 10.2±6.2 years and they were 75 females and 13 males. ACPA was positive in 84 (95.5%). The frequency of ILD among RA patients was 71.6%. ILD patterns were: usual interstitial pneumonia (UIP) 62%, non-specific interstitial pneumonia (NSIP) 27%, others (Cryptogenic and mixed) in 11%. In RA-ILD, the mean ACPA titer was 225±121.5 U/mL versus 154.3 ±121.8 U/mL in RA only. In RA-ILD, ACPA titer negatively correlated with morning stiffness, CDAI, MHAQ and six-minute walk test (r=−0.3, p=.008, r=−0.6, p<.0001, r=−0.5, p<.0001 and r=−0.5, p<.0001 respectively), while it significantly correlated with IPF severity score (r=0.09, p<.0001) and erythrocyte sedimentation rate (ESR) (r=0.5, p<.0001). ConclusionILD frequency has increased among RA patients due to improved detection by HRCT. High titer of ACPA was associated with extent and patterns of severity of ILD in RA patients. When high ACPA titer is associated with low CDAI score, physician could suspect lung involvement.