Background Lung involvement in connective tissue diseases (CTDs) is a significant cause of morbidity and mortality. The most frequent pulmonary component affected is the interstistium. The most common histopathologic pattern of interstitial lung disease (ILD) is the non-specific interstitial pneumonia (NSIP), but in rheumatoid arthritis (RA) usual interstitial pneumonia (UIP) predominates. ILD complicates the course of CTDs, although the overall survival remains higher than in idiopathic pulmonary fibrosis (IPF).
Objectives To detect in rheumatoid arthritis (RA) and systemic sclerosis (SSc) the prevalence of ILD. To find correlations with clinical manifestations and treatment schedules. To assess by a three year follow-up study the entity of lung impairment throughout pulmonary function tests (PFT).
Methods This is a three years longitudinal study including 87 RA and 31 SSc patients who underwent High Resolution Computed Tomography (HRTC) and PFT. All subjects with PFT follow-up made after 1 or 3 years from the diagnosis were selected. PFT at “Time zero” (T0) and after 3 years (T3) of 24 RA patients and PFT at “Time zero” (T0), after 1 year (T1) and after 3 years (T3) of 16 SSc patients were compared.
Results Baseline HRTC images showed ILD in 90% of RA patients and in 80% of SSc patients. After a 3-years follow-up an accelerated decline in lung function was observed, especially in terms of Total Lung Capacity (TLC). Particularly, SSc patients have shown baseline lower values of TLC than RA patients (88,25 vs 94). At T3 follow-up the TLC median value was reduced to 78,86 in SSc patients and to 91,67 in RA patients. The Delta value in comparison to the baseline is 11.39 in SSc and 2.33 in RA patients, p<0.05. TLC values at T1 and T3 are lower in anti-Scl70 SSc patients in comparison with those with anti-centromer or anti-nuclear antibodies. No significant differences were observed in TLC and in forced expiratory volume in one second (FEV1) trends by correlating patients with treatment schedules (steroids, disease modifying antirheumatic drugs (DMARDs), intravenous or per os vasodilatative drugs). To detect the factors influencing TLC values a multivariated analysis of variance was performed including the following: age, disease duration, SSc variants (diffuse/limited), anti-centromer/anti-Scl70 positivity, DMARDs/vasodilatative drugs therapy, steroids dosage, presence of pulmonary arterial hypertension. None of the determinants reached the statistical significance (low R2 value).
Conclusions HRTC is useful in identifying lung involvement at a relative early CTDs stages. The worsening of lung function is more remarkable in terms of TLC, which decreases after three-years follow-up more significantly in SSc than in RA patients. These data are more evident in anti-Scl70 SSc patients. No treatment schedule produced regression of the radiological and clinical patterns.
De Lauretis A, Veeraraghavan S, Renzoni E. Review series: aspects of interstitial lung disease: connective tissue disease-associated interstitial lung disease: how does it differ from IPF? How should the clinical approach differ? Chron Respir Dis 2011; 8:53-82.
Disclosure of Interest None Declared
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