The Borg scale is a sustainable method for prescribing and monitoring self-administered aerobic endurance exercise in patients with chronic kidney disease

Figures & data

Figure 1. Flow of patients across various phases of the trial. Recontinued shows patients performing the 6MWT after not performing the 6MWT at the previous control. One patient did not perform the 6MWT at baseline and was therefore not analysed in this sub-study.

Flow chart of patients across various phases of the trial.

Table 1. Clinical characteristics of 147 patients at baseline.

Characteristics	Mean ± SD
Age (years)	66 ± 14
Weight (kg)	82 ± 18
Height (m)	1.72 ± 0.09
BMI (kg/m^2)	28 ± 5
mGFR (mL/min/1.73m^2)	22 ± 8
Comorbidities	%
Malignancy	14
Diabetes Mellitus	33
Left Ventricular Dysfunction	10
Ischemic Heart Disease	20
Peripheral Vascular Disease	21
Other comorbidities	76

BMI; body mass index; mGFR: measured glomerular filtration rate.

Table 2. Adherence and exercise performance.

	0–4 months	4–8 months	8–12 months
Patients reporting intensity as RPE/week (n (%))	109 (89)	93 (88)	80 (80)
Intensity of aerobic endurance exercise (RPE/week*)	13 (13–15)	13 (13–15)	13 (13–15)
Patients reached goal of 13–15 RPE/week (%)	78	74	74
RPE/week < 13 (%)	17	16	17
RPE/week > 15 (%)	5	10	9
Patients reporting duration, minutes/week (n (%))	117 (95)	97 (92)	86 (86)
Duration of aerobic endurance exercise (minutes/week*)	73 (35–108)	63 (31–120)	60 (31–107)
Patients reached goal of 60 min/week (%)	56	58	52
Total training time** (minutes)	2251 (1505–3361)	2100 (1130–3310)	1740 (1033–2906)

*Median (25th–75th percentile), RPE Rating of perceived exertion, **Aerobic endurance exercise + balance or strength training.

Table 3. Results for the 6MWT and change in walking distance after 4, 8 and 12 months of exercise.

	Patients (n)	6MWT (m(±SD))	6MWT (% of predicted norm)	Delta 6MWT (p-value)
Baseline	147	402 ± 137	79	NA
4 months	123	423 ± 149	82	p = .245
8 months	106	427 ± 147	83	p = .183
12 months	100	460 ± 130	89	p < .001

6MWT: 6-m inute walk test; p-value from the paired t-test. The p-value is = 6.743e-07, therefore stated as less than 0.001. We considered a p-value of less than 0.05 as significant as stated in our methods section.

Figure 2. The patients’ performance in the 6MWT at baseline relative to the predicted norm in relation to the difference in walking distance in metres after 12 months of exercise.

Bland-Altman plot of patients performance in 6MWT at baseline in relation to difference in walking distance after the intervention.

Table 4. Increase in 6MWT after 12 months of training grouped according to the different levels of weekly duration of aerobic endurance exercise.

Minutes/week	0–14	15–29	30–44	45–59	≥60
Patients (n)	10	10	17	15	48
mGFR (mL/min/1.73m^2)	18 ± 6	21 ± 8	23 ± 7	24 ± 9	23 ± 9
Age (years)	65 ± 17	67 ± 18	69 ± 8	67 ± 12	66 ± 13
6MWT at baseline (% of predicted norm)	70 ± 21	71 ± 24	84 ± 26	92 ± 16	87 ± 14
6MWT at baseline (metres)	368 ± 154	357 ± 129	413 ± 140	461 ± 95	455 ± 87
Delta 6MWT (% of predicted norm)	4 ± 12	6 ± 11	6 ± 14	8 ± 7	6 ± 10
Delta 6MWT (metres)	22 ± 59	26 ± 51	25 ± 73	38 ± 37	31 ± 56
RPE/week	13 (13–14)	14 (13–15)	14 (13–14)	13 (13–15)	13 (13–15)

Mean ± SD or Median values (25th–75th percentile), mGFR measured glomerular filtration rate, 6MWT 6-minute walk test, RPE Rating of perceived exertion.

Figure 3. Change in walking distance in metres after 12 months for patients grouped according to different levels of exercise duration per week.

Box plot showing change in walking distance (m) for patients grouped according to different levels of exercise duration.