Table 2. Association of Outcomes With Systolic BP Indexes Without or With Adjustment for 24-Hour or Nighttime Systolic BPa.
| Outcomes | Adjusted | Additionally Adjusted Systolic BPb | ||||
|---|---|---|---|---|---|---|
| 24 Hours | Nighttime | |||||
| Hazard Ratio (95% CI)c | P Value | Hazard Ratio (95% CI)c | P Value | Hazard Ratio (95% CI)c | P Value | |
| Total Mortality (n = 2836) | ||||||
| Systolic BP index | ||||||
| Conventional | 1.12 (1.08-1.17) | <.001 | 1.05 (1.01-1.10) | .03 | 1.05 (1.01-1.10) | .02 |
| Automated office systolic BP | 1.08 (1.04-1.12) | <.001 | 0.97 (0.92-1.02) | .23 | 1.00 (0.96-1.05) | .94 |
| Measure times | ||||||
| 24 hours | 1.22 (1.16-1.28) | <.001 | NA | NA | 0.98 (0.88-1.08) | .68 |
| Daytime | 1.14 (1.09-1.20) | <.001 | 0.78 (0.69-0.88) | <.001 | 0.98 (0.92-1.05) | .64 |
| Nighttime | 1.23 (1.17-1.28) | <.001 | 1.24 (1.14-1.36) | <.001 | NA | NA |
| Dipping ratiod | 1.13 (1.09-1.18) | <.001 | 1.11 (1.06-1.15) | <.001 | 1.02 (0.97-1.07) | .46 |
| All Cardiovascular Outcomes (n = 2049) | ||||||
| Systolic BP index | ||||||
| Conventional | 1.20 (1.15-1.26) | <.001 | 1.05 (1.00-1.11) | .06 | 1.09 (1.04-1.14) | .001 |
| Automated office | 1.19 (1.14-1.24) | <.001 | 0.98 (0.93-1.04) | .58 | 1.07 (1.02-1.12) | .007 |
| Measure times | ||||||
| 24 hours | 1.45 (1.37-1.54) | <.001 | NA | NA | 1.25 (1.11-1.41) | <.001 |
| Daytime | 1.33 (1.26-1.41) | <.001 | 0.77 (0.67-0.89) | <.001 | 1.11 (1.03-1.20) | .005 |
| Nighttime | 1.36 (1.30-1.43) | <.001 | 1.16 (1.05-1.28) | .004 | NA | NA |
| Dipping ratiod | 1.14 (1.08-1.19) | <.001 | 1.08 (1.03-1.13) | <.001 | 0.92 (0.87-0.98) | .008 |
| Cardiovascular Mortality (n = 1073) | ||||||
| Systolic BP index | ||||||
| Conventional | 1.22 (1.15-1.29) | <.001 | 1.07 (1.00-1.15) | .06 | 1.09 (1.02-1.17) | .008 |
| Automated office | 1.19 (1.12-1.26) | <.001 | 0.97 (0.90-1.05) | .44 | 1.05 (0.98-1.12) | .14 |
| Measure times | ||||||
| 24 hours | 1.48 (1.36-1.60) | <.001 | NA | NA | 1.17 (1.00-1.37) | .06 |
| Daytime | 1.34 (1.24-1.45) | <.001 | 0.75 (0.62-0.91) | .003 | 1.09 (0.98-1.20) | .10 |
| Nighttime | 1.41 (1.32-1.50) | <.001 | 1.26 (1.10-1.44) | <.001 | NA | NA |
| Dipping ratiod | 1.17 (1.10-1.25) | <.001 | 1.12 (1.05-1.19) | <.001 | 0.95 (0.88-1.03) | .18 |
| Coronary Outcomes (n = 922) | ||||||
| Systolic BP index | ||||||
| Conventional | 1.14 (1.07-1.22) | <.001 | 1.01 (0.94-1.10) | .72 | 1.04 (0.97-1.12) | .30 |
| Automated office | 1.18 (1.11-1.26) | <.001 | 1.04 (0.95-1.13) | .41 | 1.08 (1.00-1.16) | .04 |
| Measure times | ||||||
| 24 hours | 1.35 (1.24-1.47) | <.001 | NA | NA | 1.12 (0.94-1.34) | .22 |
| Daytime | 1.27 (1.16-1.38) | <.001 | 0.83 (0.67-1.03) | .09 | 1.07 (0.96-1.20) | .23 |
| Nighttime | 1.30 (1.21-1.40) | <.001 | 1.20 (1.03-1.40) | .02 | NA | NA |
| Dipping ratiod | 1.13 (1.05-1.21) | <.001 | 1.09 (1.01-1.17) | .02 | 0.95 (0.87-1.04) | .30 |
| Stroke (n = 822) | ||||||
| Systolic BP index | ||||||
| Conventional | 1.30 (1.21-1.40) | <.001 | 1.11 (1.02-1.21) | .02 | 1.16 (1.07-1.26) | <.001 |
| Automated office | 1.24 (1.16-1.33) | <.001 | 0.99 (0.90-1.08) | .76 | 1.10 (1.02-1.19) | .01 |
| Measure times | ||||||
| 24 hours | 1.60 (1.46-1.76) | <.001 | NA | NA | 1.36 (1.14-1.63) | .001 |
| Daytime | 1.45 (1.33-1.58) | <.001 | 0.80 (0.65-1.00) | .05 | 1.19 (1.06-1.33) | .003 |
| Nighttime | 1.46 (1.36-1.58) | <.001 | 1.17 (1.01-1.36) | .04 | NA | NA |
| Dipping ratiod | 1.14 (1.06-1.23) | <.001 | 1.08 (1.01-1.16) | .03 | 0.87 (0.80-0.96) | .004 |
Abbreviations: BP, blood pressure; NA, not applicable.
a
All models accounted for cohort, sex, age, body mass index, smoking and drinking, serum cholesterol, antihypertensive drug intake, history of cardiovascular disease, and diabetes mellitus.
b
Models including 2 correlated systolic BP indexes were constructed, using the residual method (see Statistical Analysis section).
c
Hazard ratios express the risk for increments of 20 mm Hg in systolic BP and 0.10 in the dipping ratio.
d
The dipping ratio is calculated by dividing nighttime by daytime systolic BP.