Purpose: Decline in physical function is commonly observed in patients with kidney failure on dialysis. Whether lung congestion, a predictable consequence of cardiomyopathy and fluid overload, may contribute to the low physical functioning of these patients has not been investigated.
Methods: In 51 peritoneal dialysis (PD) patients, we investigated the cross-sectional association between the physical functioning scale of the Kidney Disease Quality of Life Short Form (KDQOL-SF: Rand Corporation, Santa Monica, CA, USA) and an ultrasonographic measure of lung water recently validated in dialysis patients. The relationship between physical functioning and lung water was also analyzed taking into account the severity of dyspnea measured using the New York Heart Association (NYHA) classification currently used to grade the severity of heart failure.
Results: Evidence of moderate-to-severe lung congestion was evident in 20 patients, and this alteration was asymptomatic (that is, NHYHA class I) in 11 patients (55%). On univariate analysis, physical functioning was inversely associated with lung water (r = -0.48, p < 0.001), age (r = -0.44, p = 0.001), previous cardiovascular events (r = -0.46, p = 0.001), and fibrinogen (r = -0.34, p = 0.02). Physical functioning was directly associated with blood pressure, the strongest association being with diastolic blood pressure (r = 0.38, p = 0.006). The NYHA class correlated inversely with physical functioning (r = -0.51, p < 0.001). In multiple regression analysis, only lung water and fibrinogen remained independent correlates of physical functioning. The NYHA class failed to maintain its independent association.
Conclusions: This cross-sectional study supports the hypothesis that symptomatic and asymptomatic lung congestion is a relevant factor in the poor physical functioning of patients on PD.