Table 5.
Cox proportional hazards models to assess risk of first major cardiovascular event among women with incident diagnosis of hypertension during first 48 months of follow-up (n=38 787)
| Hazard ratio (95% confidence interval) | P trend | ||||
|---|---|---|---|---|---|
| No progression* (n=22 886) | Progression to hypertension* (n=5694) | Baseline hypertension* (n=10 207) | |||
| First model | |||||
| Events/person years | 214/137 767 | 106/34 038 | 332/60 250 | ||
| Crude | 0.50 (0.40 to 0.63) | 1.0† | 1.77 (1.42 to 2.20) | <0.0001 | |
| Age adjusted‡ | 0.60 (0.48 to 0.76) | 1.0† | 1.51 (1.22 to 1.89) | <0.0001 | |
| Multivariable adjusted§ | 0.64 (0.50 to 0.81) | 1.0† | 1.39 (1.11 to 1.74) | <0.0001 | |
| Second model | (From below high normal)¶ | (From high normal)¶ | |||
| Events/person years | 214/137 767 | 47/19 622 | 59/14 416 | 332/60 250 | |
| Crude | 0.38 (0.29 to 0.51) | 0.59 (0.40 to 0.86) | 1.0† | 1.35 (1.02 to 1.78) | <0.0001 |
| Age adjusted‡ | 0.50 (0.37 to 0.66) | 0.68 (0.46 to 1.00) | 1.0† | 1.25 (0.95 to 1.65) | <0.0001 |
| Multivariable adjusted§ | 0.53 (0.40 to 0.72) | 0.70 (0.47 to 1.03) | 1.0† | 1.17 (0.88 to 1.55) | <0.0001 |
*No progression defined as a blood pressure <140/90 mm Hg at baseline and during at least 48 months of follow-up in absence of blood pressure lowering treatment; progression to hypertension defined as blood pressure <140/90 mm Hg without blood pressure lowering treatment at baseline and developing hypertension during first 48 months of follow-up; hypertension defined as previous diagnosis of hypertension, systolic blood pressure ≥140 mm Hg, diastolic blood pressure ≥90 mm Hg, or receiving blood pressure lowering treatment at baseline.
†Reference category.
‡Age at 48 months of follow-up used for adjustment.
§Adjusted for age, smoking, diabetes, body mass index, and alcohol consumption at 48 months and for baseline history of hypercholesterolaemia, exercise, highest educational level, and randomised treatment assignments (aspirin, vitamin E, and β carotene); owing to missing covariates, the multivariable analysis was based on 625 (compared with 652 in the crude and age adjusted analyses) major cardiovascular events during follow-up among 37 653 women.
¶Group of women with progression to hypertension divided into 3274 women who had a baseline blood pressure <130/85 mm Hg (below high normal) and 2420 who had baseline blood pressure 130-9/85-9 mm Hg (high normal).