Physical capacity in performing daily activities is reduced in scleroderma patients with early lung involvement

Patients with systemic sclerosis (SSc) often complain reduced capacity at submaximal exercise; conversely, physical capacity in performing daily duties has never been measured in SSc. The aim of this study is to evaluate this performance and its correlates, in patients with SSc compared with healthy controls, in a free-living setting.

Twenty-seven outpatients with stable SSc and 11 controls were recruited. Physical activity was assessed by portable multiple sensor device (SenseWear Armband) worn for at least 6 days. Physical activity duration (PAD; in minutes) for non-sedentary activities and physical activity level (PAL = total daily energy/resting energy expenditure) per day were calculated. Nutritional status was estimated by bioelectrical impedance analysis and pulmonary arterial hypertension excluded by echocardiography.

Daily physical activities (243 ± 145 min per day vs 397 ± 142 min, respectively; P = 0.005) and PAL were significantly reduced in SSc compared with controls (1.5 ± 0.4 vs 2 ± 0.7, respectively; P = 0.019). Seventy-four per cent of SSc patients showed PAL < 1.70, whereas only 27% of controls were below this threshold for sedentary life style. Both PAD and PAL positively correlated with DLco. Patients and controls did not differ for spirometric parameters, body mass index, phase angle at bioelectrical impedance analysis, fat mass or fat-free mass indexes. In SSc, exercise capacity during daily activity was reduced compared with controls, and was associated with early evidence of functional decay (decreasing DLco) but not with malnutrition (undernutrition).

A reduction of daily physical activity is already present even in early stages of lung involvement in SSc, characterized by unaltered spirometry and well-preserved nutritional status.