AB 1. Prevalence and etiology of reduced exercise capacity among patients with scleroderma

Abstract

Background Scleroderma is a connective tissue disorder characterized by reduced exercise tolerance. The aim of the study is: (I) to estimate the prevalence of decreased maximum exercise capacity, (II) to investigate the cause of this functional limitation (respiratory or cardiovascular disorders) and (III) to study potential differences of clinical, radiological, functional characteristics and blood serology among scleroderma patients with functional limitation of different etiology.

Material and methods A consecutive population of 82 scleroderma patients (11.9% male; 49.8 years old and 88.1% female; 54.9 years old), who were evaluated at the respiratory physiology laboratory of the Respiratory Failure Unit, constituted the study population. Patients underwent spirometry, measurement of diffusion capacity, resting Doppler echocardiography and maximum cardiopulmonary exercise testing on a cycle ergometer. Data on previous thorax computed tomography and blood serology were also recorded. Breathing Reserve at the end of exercise was calculated as: BR = (FEV ×40) - peak minute ventilation. Patients with BR

Results Exercise capacity was normal in 37.8% of patients (group N), reduced exercise capacity due to respiratory limitation in 12.2% (group R) and reduced exercise capacity due to circulatory limitation in 50% (group C). Patients of group R, compared to those of group C, were older (61.3 48.3 years old; P=0.018), had a more severe respiratory restriction (measured by TLC%) (61.3 84.5; P