Table 2.
Skeletal muscle oxygen saturation characteristics and incremental exercise performance in CKD patients
| Aerobic capacity (based on the ISWT) tertiles | ||||
|---|---|---|---|---|
| ‘Lower’ (n = 8) | ‘Middle’ (n = 8) | ‘Upper’ (n = 8) | P | |
| Age (years) | 72.0 (± 8.1) | 57.5 (± 13.7)a,* | 45.3 (15.2) a,* | .002* |
| Sex, n female (%) | 3 (38%) | 4 (50%) | 2 (25%) | .587 |
| eGFR (ml/min/kg/1.73 m2) | 48.8 (± 21.9) | 58.0 (± 16.4) | 64.0 (± 26.4) | .435 |
| ISWT (distance walked, m) | 269.0 (± 35.9) | 479.6 (± 36.0)a,* | 727.1 (± 38.1)a,*, b,* | < .001* |
| Baseline SMO2 (%) | 66.6 (± 3.0) | 70.3 (± 2.4) | 73.6 (± 2.8) | .326 |
| Minimum % reached (%) | 62.5 (± 3.2) | 60.5 (± 2.5) | 64.5 (± 2.9) | .586 |
| Time to min (s) | 268.6 (± 65.3) | 352.6 (± 52.0) | 491.7 (± 60.5)a,* | .099 |
| % Drop (%) | 9.0 (± 2.1) | 9.8 (± 1.7) | 8.7 (± 2.0) | .888 |
| % Change (% of baseline) | 13.5 (± 3.3) | 14.2 (± 2.6) | 11.8 (± 3.1) | .844 |
| Recovery ½ time (s) | 58.6 (± 12.9) | 51.1 (± 10.3) | 12.2 (± 11.9)a,*, b,* | .046* |
| Recovery full time (s) | 126.6 (± 27.0) | 88.2 (± 20.0) | 41.1 (± 23.0)a,* | .121 |
| % after 3 min recovery (%) | 65.7 (± 2.8) | 74.3 (± 2.3)a,* | 78.4 (± 2.6)a,* | .025* |
| Overshoot (% of baseline) | − 0.9 (± 2.3) | 5.7 (± 1.8),* | 6.6 (± 2.1)a,* | .071 |
Controlling for differences age and sex, data presented as estimated marginal means (± SE)
CKD chronic kidney disease, eGFR estimated glomerular filtration rate, ISWT incremental shuttle walk test, SMO2 skeletal muscle oxygen (%)
*P < .050
a,*Significant (P < .050) difference from ‘lower’
b,*Significant (P < .050) difference from ‘middle’