Table 2.
Baseline heart rate variability parameters of study groups
| Variable | Control (n=87) | Stage 5 CKD Patients (n=118) | P | Non-PTX Group (n=81) | PTX Group (n=37) | |||
|---|---|---|---|---|---|---|---|---|
| Nonfollow-Up (n=16) | Successful PTX Follow-Up (n=17) | Unsuccessful PTX Follow-Up (n=4) | Total (n=37) | |||||
| Mean 24-h HR (beats/min) | 76.8±8.0 | 82.3±10.9 | <0.001 | 80.9±11.0 | 86.4±8.3 | 87.1±10.7 | 73.0±8.1 | 85.5±9.9 |
| Time domain measures | ||||||||
| Mean NN (ms) | 789.3±80.7 | 743.0±103.5 | <0.001 | 756.9±107.8 | 701.4±70.1 | 699.7±91.5 | 833.0±91.5 | 712.6±87.2 |
| SDNN (ms) | 140.9±34.9 | 82.7±48.4 | <0.001 | 85.8±54.9 | 80.9±33.1 | 67.8±24.6 | 94.0±27.0 | 76.1±29.3 |
| SDANN (ms) | 128.4±34.2 | 74.7±61.5 | <0.001 | 78.4±71.5 | 71.9±31.1 | 57.9±25.4 | 81.0±28.1 | 66.6±28.7 |
| rMSSD (ms) | 29.8±11.2 | 19.2±9.3 | <0.001 | 19.6±9.7 | 16.9±6.9 | 19.5±9.9 | 18.0±5.7 | 18.3±8.3a |
| pNN50% | 9.2±8.7 | 3.2±4.7 | <0.001 | 3.4±4.7 | 1.8±2.7 | 3.7±6.5 | 1.7±1.7 | 2.7±4.9 |
| Frequency domain measures | ||||||||
| VLF (ms2) | 1012.8 (646.0–1571.8) | 232.7 (112.1–473.6) | <0.001 | 210.1 (107.4–459.2) | 381.2 (139.4–472.4) | 164.4 (107.8–484.6) | 570.1 (154.8–1147.5) | 311.8 (119.6–485.4) |
| LF (ms2) | 177.5 (16.8–395.2) | 59.5 (21.6–150.5) | 0.02 | 50.8 (18.3–149.2) | 72.9 (24.8–124.4) | 79.1 (46.3–165.6) | 65.2 (9.2–533.5) | 74.2 (35.7–159.7) |
| HF (ms2) | 56.7 (1.6–189.0) | 26.0 (10.3–61.6) | 0.37 | 27.4 (9.6–63.4) | 21.0 (8.0–45.7) | 27.6 (18.5–81.4) | 22.1 (3.1–84.4) | 24.0 (12.1–56.1) |
| LF/HF | 4.0 (2.0–11.8) | 2.8 (1.5–5.3) | <0.001 | 2.3 (1.3–5.1) | 3.9 (2.7–5.9) | 3.1 (1.6–4.3) | 8.4 (2.0–15.3) | 3.5 (2.3–5.9) |
| ln VLF [ln(ms2)] | 6.9±0.6 | 5.5±1.0 | <0.001 | 5.4±1.1 | 5.7±1.1 | 5.4±1.0 | 6.1±1.1 | 5.6±1.0 |
| ln LF [ln(ms2)] | 4.5±1.7 | 4.0±1.4 | 0.03 | 3.9±1.4 | 4.2±1.5 | 4.4±1.0 | 4.0±2.1 | 4.3±1.3 |
| ln HF [ln(ms2)] | 2.9±2.6 | 3.0±1.6 | 0.67 | 3.0±1.7 | 2.8±1.8 | 3.4±1.1 | 2.4±2.4 | 3.1±1.6 |
| ln LF/HF | 1.6±1.0 | 1.0±1.0 | <0.001 | 0.9±1.0 | 1.4±0.8 | 1.0±0.8 | 1.6±1.6 | 1.2±0.9 |
Data are mean ± SD or median (25th to 75th percentile). Independent samples t test was used to compare stage 5 CKD patients (n=118) with controls (n=87) and nonfollow-up patients (n=16) with successful PTX follow-up patients (n=17). The Wilcoxon rank sum test was used to compare medians of untransformed frequency domain measures. Multiple linear regression analysis was used to compare the PTX group (n=37) with the non-PTX group (n=81) and the successful PTX follow-up group (n=17) with the non-PTX group (n=81) with adjustment for age, sex, dialysis vintage, diabetes, and hypertension. PTX, parathyroidectomy; HR, heart rate; mean NN, mean normal-to-normal R–R intervals; SDNN, SD of normal-to-normal R–R intervals; SDANN, SD of 5-minute average of normal R–R intervals; rMSSD, root mean square of differences between adjacent normal R–R intervals; pNN50%, proportion of adjacent R–R intervals differing by >50 ms over 24 hours; VLF, very low frequency; LF, low frequency; HF, high frequency.
P<0.05 versus non-PTX group.