PLoS One. 2017 Sep 14;12(9):e0183926

Rogan A, McCarthy K, McGregor G, Hamborg T, Evans G, Hewins
S, Aldridge N, Fletcher S, Krishnan N, Higgins R, Zehnder D,
Ting SM

BACKGROUND: Patients with advanced chronic kidney disease (CKD) experience
complex functional and structural changes of the cardiopulmonary and
musculoskeletal system. This results in reduced exercise tolerance, quality of
life and ultimately premature death. We investigated the relationship between
subjective measures of health related quality of life and objective, standardised
functional measures for cardiovascular and pulmonary health.
METHODS: Between April 2010 and January 2013, 143 CKD stage-5 or CKD5d patients
(age 46.0±1.1y, 62.2% male), were recruited prospectively. A control group of 83
healthy individuals treated for essential hypertension (HTN; age 53.2±0.9y,
48.22% male) were recruited at random. All patients completed the SF-36 health
survey questionnaire, echocardiography, vascular tonometry and cardiopulmonary
exercise testing.
RESULTS: Patients with CKD had significantly lower SF-36 scores than the HTN
group; for physical component score (PCS; 45.0 vs 53.9, p<0.001) and mental
component score (MCS; 46.9 vs. 54.9, p<0.001). CKD subjects had significantly
poorer exercise tolerance and cardiorespiratory performance compared with HTN
(maximal oxygen uptake; VO2peak 19.9 vs 25.0ml/kg/min, p<0.001). VO2peak was a
significant independent predictor of PCS in both groups (CKD: b = 0.35, p = 0.02
vs HTN: b = 0.27, p = 0.001). No associations were noted between PCS scores and
echocardiographic characteristics, vascular elasticity and cardiac biomarkers in
either group. No associations were noted between MCS and any variable. The
interaction effect of study group with VO2peak on PCS was not significant (ΔB =
0.08; 95%CI -0.28-0.45, p = 0.7). However, overall for a given VO2peak, the
measured PCS was much lower for patients with CKD than for HTN cohort, a likely
consequence of systemic uremia effects.
CONCLUSION: In CKD and HTN, objective physical performance has a significant
effect on quality of life; particularly self-reported physical health and
functioning. Therefore, these quality of life measures are indeed a good
reflection of physical health correlating highly with objective physical
performance measures.