Six‐minute walk test predicts all‐cause mortality and technique failure in ambulatory peritoneal dialysis patients

• Published in: Nephrology (Carlton, Vic.) Vol. 22; no. 2; pp. 118 - 124
• Main Authors: Shi, Yuanyuan, Zheng, Dongxia, Zhang, Lin, Yu, Zanzhe, Yan, Hao, Ni, Zhaohui, Qian, Jiaqi, Fang, Wei
• Format: Journal Article
• Language: English
• Published: Australia Wiley Subscription Services, Inc 01.02.2017
• Subjects: Adult; Age; Age Factors; Aged; Blood Pressure; China; Exercise Test - methods; Exercise Tolerance; Female; Health risk assessment; Heart; Hemodialysis; Humans; Kaplan-Meier Estimate; Kidney Failure, Chronic - diagnosis; Kidney Failure, Chronic - mortality; Kidney Failure, Chronic - physiopathology; Kidney Failure, Chronic - therapy; Male; Middle Aged; patient survival; Patients; Peritoneal dialysis; Peritoneal Dialysis, Continuous Ambulatory - adverse effects; Peritoneal Dialysis, Continuous Ambulatory - mortality; Peritoneum; Peritonitis; Predictive Value of Tests; prognostic value; Prospective Studies; Risk Assessment; Risk Factors; six‐minute walk test; Stroke Volume; Survival; technique survival; Time Factors; Treatment Outcome; Ventricle; Ventricular Function, Left; Walking; peritoneal dialysis; patient survival; technique survival; prognostic value; six-minute walk test
• ISSN: 1320-5358; 1440-1797
• DOI: 10.1111/nep.12726

Aim This study investigated the associated factors of 6‐min walk test (6MWT) and its predictive value of outcome in patients undergoing peritoneal dialysis (PD). Methods This is a single centre prospective observational cohort study. Stable ambulatory PD patients in our centre between 1 May 2010 and 30 April 2011 were enrolled in this study. All included subjects performed 6MWT, and 6‐min walk distances (6MWDs) were recorded. Patients were divided into two groups according to 6MWD and prospectively followed up until death, cessation of PD or to the end of the study (30 September 2012). Results A total of 145 patients were enrolled, including 63 (43%) males. Multiple stepwise regression showed that age (β = –0.295, P = 0.001), diastolic blood pressure (DBP) (β = 0.292, P = 0.001), left ventricular ejection fraction (LVEF) (β = 0.198, P = 0.019) were independently associated with lower 6MWD. By the end of the study, six (8%) patients died in long 6MWD group while 15 (20%) died in the short 6MWD group, a significantly lower patient survival was observed in short 6MWD group (Log‐rank = 4.983, P = 0.026). Patients with short 6MWD also showed inferior technique survival (Log‐rank = 4.838, P = 0.028). There was no significant difference in peritonitis‐free survival between the two groups (Log‐rank = 0.801, P = 0.371). However, more patients in short 6MWD group had been transferred to hemodialysis due to peritonitis (25% vs 4.2%, P = 0.013). Conclusion Age, diastolic blood pressure, LVEF are independent associated factors of 6MWD in patients undergoing PD. Having the advantages of easy applicability and safety, 6MWT may be proposed as an important predictor of outcome in ambulatory PD patients. Summary at a Glance This paper describes a cohort of PD patients who underwent 6 minute walk tests (6MWT). Longer distances predicted patient and technique survival, but not peritonitis. Factors associated with lower distances were examined. They included some unexpected variables (eg lower DBP) and some expected ones (eg Age/LVEF). It was proposed that this test could be used to prognosticate in PD patients. This is the first report of this test as a discriminator of technique survival. Whilst some of the conclusions appear self evident (ie if you have a better heart and are younger you might do better), some are not intuitive and worth reporting esp interesting is lower DBP and this might represent pump failure but is within the normal range so this is controversial and provocative, esp since SBP was lower in this group as well. It is well written and I think of general interest to nephrologists.