Table 3.
Standardized hazard ratios for all-cause mortality associated with mean 24-hour blood pressure and average real variability calculated from full and reduced recordings in the discovery dataset
| Minimum number of BP readings | Systolic BP | Diastolic BP | ||||||
|---|---|---|---|---|---|---|---|---|
| Mean 24-h BP | Average real variability | Mean 24-h BP | Average real variability | |||||
| Hazard ratio (95% CI) | Delta, % | Hazard ratio (95% CI) | Delta, % | Hazard ratio (95% CI) | Delta, % | Hazard ratio (95% CI) | Delta, % | |
| 80 | 1.17 (1.04–1.33)** | NA | 1.18 (1.04–1.33)** | NA | 1.18 (1.04–1.34)** | NA | 1.16 (1.02–1.32)** | NA |
| 72 | 1.17 (1.03–1.32)** | −0.3 | 1.16 (1.02–1.32)** | −1.3 | 1.18 (1.04–1.35)** | 0.3 | 1.14 (1.00–1.30)** | −1.5 |
| 64 | 1.17 (1.04–1.33)** | 0.0 | 1.15 (1.02–1.29)** | −2.5 | 1.18 (1.03–1.34)** | −0.2 | 1.12 (0.99–1.27)*** | −3.3 |
| 56 | 1.16 (1.03–1.32)** | −0.9 | 1.16 (1.03–1.31)** | −1.6 | 1.16 (1.02–1.32)** | −1.9 | 1.14 (1.00–1.29)** | −1.9 |
| 48 | 1.17 (1.03–1.32)** | −0.6 | 1.16 (1.03–1.31)** | −1.6 | 1.18 (1.04–1.35)** | 0.2 | 1.14 (1.00–1.29)** | −2.0 |
| 40 | 1.18 (1.04–1.33)* | 0.2 | 1.06 (0.93–1.20) | −10.2 | 1.18 (1.04–1.35)** | 0.4 | 1.11 (0.98–1.25)*** | −4.5 |
| 32 | 1.06 (0.94–1.21) | −9.2 | 1.01 (0.89–1.14) | −14.2 | 0.98 (0.86–1.12) | −17.0 | 1.01 (0.90–1.15) | −12.5 |
Standardized hazard ratios (95% confidence intervals (CIs)) express the risk in all-cause mortality associated with 1 SD increase in the 24-hour blood pressure (BP) or the 24-hour average real variability. The SD of the 24-hour systolic BP was 12.77mm Hg for the full recordings (at least 80 readings) and 12.79, 12.81,12.82,1 2.90, 12.92, and 12.83mm Hg for the reduced recordings including at least 72, 64, 56, 48, 40, and 32 readings, respectively. For systolic average real variability, these SDs were 2.45, 2.55, 2.66, 2.45, 3.00, 3.21, and 3.40mm Hg, respectively. The corresponding SDs for the 24-hour diastolic BP and the diastolic average real variability were 8.38, 8.38, 8.42, 8.43, 8.46, 8.51, and 8.46mm Hg; and 1.36,1.42, 1.50, 1.62, 1.72, 1.86, and 2.01mm Hg, respectively. All hazard ratios were computed by Cox regression and were adjusted for sex and age. Delta is the percent difference between the hazard ratio calculated from the reduced recording and the hazard ratio calculated from the full recording.
Abbreviation: NA, not applicable.
Significance of the hazard ratios: *P < 0.01; **P < 0.05; ***0.05 ≤ P < 0.10.