Sample size estimates and the impact on the precision of the study results, taking into account uncertainty about the expected prevalence of normotension and white coat hypertension
| Sustained hypertensive (true positive) | Normotensive (true negative) | White coat hypertensive (false positive) | Masked hypertensive (false negative) | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Scenario | Sample size | Point estimate | Predicted CI | Point estimate | Predicted CI | Point estimate | Predicted CI | Point estimate | Predicted CI |
| Prevalences observed in the original PROOF-BP study19 | 1000 | 71% | 68% to 74% | 24% | 21% to 27% | 3% | 2% to 4% | 2% | 1% to 3% |
| 800 | 71% | 68% to 74% | 24% | 21% to 27% | 3% | 2% to 4% | 2% | 1% to 3% | |
| Prevalence of normotension decreases by 50% | 1000 | 83.5% | 81% to 86% | 12% | 10% to 14% | 3.5% | 2% to 5% | 1% | 0.5% to 2% |
| 800 | 83.5% | 81% to 86% | 12% | 10% to 14% | 3.5% | 2% to 5% | 1% | 0.5% to 2% | |
| Prevalence of normotension decreases by 75% | 1000 | 89.5% | 87% to 91% | 6% | 5% to 8% | 4% | 3% to 5% | 0.5% | 0% to 1% |
| 800 | 89.5% | 87% to 92% | 6% | 4% to 8% | 4% | 3% to 6% | 0.5% | 0% to 1% | |
| Prevalence of white coat hypertension increases by 50% | 1000 | 69.5% | 67% to 72% | 24% | 21% to 27% | 4.5% | 3% to 6% | 2% | 1% to 3% |
| 800 | 69.5% | 66% to 73% | 24% | 21% to 27% | 4.5% | 3% to 6% | 2% | 1% to 3% | |
| Prevalence of white coat hypertension increases by 100% | 1000 | 68% | 65% to 71% | 24% | 21% to 27% | 6% | 5% to 8% | 2% | 1% to 3% |
| 800 | 68% | 65% to 71% | 24% | 21% to 27% | 6% | 4% to 8% | 2% | 1% to 3% | |
PROOF-BP, predicting out-of-office blood pressure in the clinic.