Asymptomatic pulmonary congestion and physical functioning in hemodialysis patients

Abstract

Background and objectives: Poor physical performance is common in patients with kidney failure on dialysis (CKD-5D). Whether lung congestion, a predictable consequence of cardiomyopathy and fluid overload, may contribute to the low physical performance of CKD-5D patients has not been investigated in hemodialysis patients.

Design, setting, participants, & measurements: This study investigated the relationship between the physical functioning scale of the Kidney Disease Quality of Life Short Form and a validated ultrasonographic measure of lung water in a multicenter survey of 270 hemodialysis patients studied between 2009 and 2010.

Results: Moderate to severe lung congestion by lung ultrasonography was observed in 156 (58%) patients; among these, 60 (38%) were asymptomatic (New York Heart Association [NYHA] class I). On univariate analysis, physical functioning was inversely associated with lung water in the whole group (r=-0.22; P<0.001) and in the subgroup of asymptomatic patients (r=-0.40; P=0.002). Age (r=-0.45; P<0.001) and past cardiovascular events (r=-0.22; P=0.002) were also inversely associated with physical functioning, whereas albumin (r=0.23; P<0.001) was directly associated with the same parameter. NYHA class correlated strongly with physical functioning (r=-0.52; P<0.001). In a multiple regression analysis, both NYHA class and lung water maintained an independent association with physical functioning, whereas albumin and background cardiovascular events failed to independently relate with the same outcome.

Conclusions: Symptomatic and asymptomatic lung congestion is associated with poor physical functioning in hemodialysis patients. This association is independent of NYHA, suggesting that this measurement and NYHA may have complementary value to explain the variability in physical performance in hemodialysis patients.

Figure 1.

Flow-diagram showing enrollment of hemodialysis patients. KDQOL-SF, Kidney Disease Quality of Life Short Form.

Figure 2.

Bar graph of the physical functioning score distribution. The vertical arrow indicates the 75th percentile (corresponding to the 25th percentile of the distribution of the same score in the Italian general population) [see Apolone and Mosconi (12)].

Figure 3.

Relationship between ultrasound B line score and physical functioning in patients scored as NYHA class I. NYHA, New York Heart Association; KDQOL-SF, Kidney Disease Quality of Life Short Form; USB, ultrasound B line.

Figure 4.

Median and interquartile range of physical functioning according to NYHA class and mental health score tertiles. The relationship between variables is also expressed as the correlation coefficient and P value. NYHA, New York Heart Association; KDQOL-SF, Kidney Disease Quality of Life Short Form.