Table 3.
Reliability of home BP measurement in each period
| Variable (days 1 to 7 vs days 8 to 14) | No. | ICC (1,1) | Bland‐Altman analysis | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Intraclass correlation | 95% CI | Fixed bias | Proportional bias | LOA, mm Hg | Random error | Repeatability coefficient | Percentage of near‐maximal variability | ||||
| 95% CI | Bias | Slopea (P value) | Bias | MDC, mm Hg | |||||||
| Systolic BP | |||||||||||
| Morning | 48 | 0.928 | 0.875–0.959 | 0.470–2.944 | Yes | 0.273 (.061) | No | −4.5 to 12.2 | – | 8.5 | 18.1 |
| Before dinner | 47 | 0.851 | 0.749–0.914 | 0.287–4.729 | Yes | −0.038 (.798) | No | −8.5 to 21.2 | – | 15.1 | 27.2 |
| At bedtime | 45 | 0.852 | 0.747–0.915 | −1.102 to 3.117 | No | 0.127 (.406) | No | – | 13.8 | 14.0 | 28.3 |
| Diastolic BP | |||||||||||
| Morning BP | 48 | 0.927 | 0.874–0.958 | 0.193–1.863 | Exist | −0.111 (.451) | No | −3.2 to 8.1 | – | 5.8 | 18.5 |
| Before dinner | 47 | 0.903 | 0.834–0.945 | −0.437 to 2.027 | No | −0.111 (.460) | No | – | 8.3 | 8.5 | 22.4 |
| At bedtime | 45 | 0.901 | 0.828–0.944 | −0.847 to 1.385 | No | −0.160 (.293) | No | – | 7.5 | 7.7 | 23.0 |
BP, blood pressure; CI, confidence interval; ICC, intraclass correlation coefficient; LOA, limits of agreement; MDC, minimal detectable change.
a
Slope of regression line.