Exercise as it relates to Disease/Effects of exercise in Chronic Kidney Disease patients

This is an analysis of the journal article "Effects of a Renal Rehabilitation Exercise Program in Patients with CKD: A Randomized, Controlled Trial" by Rossi AP, Burris DD, Lucas FL,Crocker GA and Wasserman JC (2014). It was published in the Clinical Journal of the American Society of Nephrology.

What is the background to this research?
Chronic kidney disease (CKD) is the progressive deterioration in renal function. CKD patients are found to have a higher rate of cardiovascular disease (CVD), which has been associated with the inactivity levels of the patient, leading to poorer cardiorespiratory fitness. While there has been research into exercise and CKD in the past, the optimal exercise program has not been established. This study was conducted to determine whether a patient's physical functioning and quality of life (QOL) would benefit from a predetermined renal rehabilitation exercise (RRE).

Where is the research from?
The research took place at Maine Nephrology Associates, a nephrology practice in Portland, Maine. A number of approved physical therapy and cardiac rehabilitation centres were selected in the greater Portland area to be used for the RRE groups exercises.

The author does not state any possible conflicts of interest, but the article states that the study had been approved by Maine Medical Center Institutional Review Board and was also registered with ClinicalTrials.gov.

What kind of research was this?
The study was a single-centre, randomised, controlled trial (RCT) that spanned 12 weeks. RCTs are considered the 'gold standard' in research as they are controlled experiments which exclude bias when selecting control and intervention groups. Ideally studies are double-blinded, meaning that both the participant and the assessor are unsure as to which group they are part of, or are assessing. One limitation of the study was that due to the type of intervention, blinding of both parties was not possible.

What did the research involve?
Both groups were provided with the normal standard of care outlined in the Kidney Disease Improving Global Outcomes guidelines. This care was delivered through the participants' primary nephrologist. The RRE group also received two guided exercise sessions per week for 12 weeks. The RRE group was able to complete their exercises from a selection of healthcare facilities in the greater Portland area. The exercise sessions were held either as group classes or with the individual and included stretching exercises, cardiovascular and weight training. The research compared the baseline and post-intervention measures of both groups in the 6 minute-walk-test (6MWT), sit-to-stand-test (STST), gait-speed-test (GST) and RAND-36 QOL test.

The cardiovascular exercises consisted of either treadmill walking or the stationary bike. In each session the participants had to increase the length of exercise by 2-3 minutes with the aim to cycle or walk for 60 minutes continuously. The intensity of the exercises was also increased each session by adding resistance to the bicycle or increasing speed and elevation on the treadmill.

Weight training focused on using free weights to strengthen both upper and lower limbs. The aim was to increase the amount of repetitions from one set of 10 repetitions to three sets of 15 repetitions. After this was accomplished, the weight was increased.

The information regarding stretching was limited, only stating that they were described in the Dialysis Patients' Guide to Exercise.

There were several limitations with the study:
 * Single or double blinding was not possible for this study
 * Unbalanced sex distribution between both groups. Greater number of females in the RRE group, while the males in the RRE group recorded greater physical improvements
 * High rate of participants discontinuing the RRE (18.6%)
 * Compliance issues with exercise protocols
 * RRE group had a higher baseline GST than UC group. The author stated that this could mean the RRE group was already physically fitter than the UC group
 * Participants required certain level of health as they had to travel to a facility for the exercise

What were the basic results?
The study determined that there were significant positive effects for those with stage 3 and 4 CKD. Significant improvements were recorded in the 6MWT and STST. Physical functioning and pain QOL measures and were also found to improve.

At baseline, both groups were of a similar physical function, with comparable 6MWT and STST scores. After the 12-week exercise routine, the RRE group had gained significant physical improvements, with a 19% increase in 6MWT scores and 29% increase in STST scores. It was found that the RRE groups baseline GST score was significantly higher than the UC group. Due to this, there was no significant difference found between both groups.

The RAND-36, QOL assessment showed significant improvements in the RRE group when compared with the UC group. The improvements were found in all physical measures and also in the pain scale, which was catergorised under mental measures. There were no improvements recorded by either group in any other mental measures.

The results from the study show that by including exercise sessions twice per week, CKD patients can experience improvements with their physical function and their quality of life.

What conclusions can we take from this research?
Although there are several limitations to the research, there are still conclusions that can be made. Patients with CKD, stages 3 and 4, who partake in exercise are able to benefit from greater physical function and have a higher quality of life. While there is no definitive evidence that exercising with CKD will slow the progression of the disease, there is no evidence that exercise negatively affects the patients' kidneys. .

The research was able to show that a RRE program can be included as part of the standard clinical care provided. This is possible as the exercise sessions can be held in multiple locations with other trained health professionals.

In other research it has been found that exercise has reduced systolic and diastolic blood pressure in CKD patients.

It is also clear that further studies with a greater sample size and longer follow-up are required. This will assist in having a better randomisation of groups, provide more accurate results and will provide information on any long-term effects of exercise on CKD.

Practical advice
The evidence shows the patient should start at a moderate intensity and increase this overtime. Through exercise the patient will also receive other benefits of increased energy levels, maintaining strength and body weight and a reduction in stress.

A nephrologist should be consulted if the patient experiences any pain, feels unwell or has any questions regarding exercise and CKD.

For further information regarding kidney disease, treatments and exercise, see below:

Kidney Health Australia: http://kidney.org.au/

Kidney Health Australia: http://kidney.org.au/your-kidneys/support/dialysis/dialysis-and-wellbeing/excercise-and-sport

National Kidney Foundation (USA): https://www.kidney.org/