Optimal Number of Days for Home Blood Pressure Measurement

BACKGROUND Current guidelines make no outcome-based recommendations on the optimal measurement schedule for home blood pressure (BP). METHODS We enrolled 4,802 randomly recruited participants from three populations. The participants were classified by their (i) cross-classification according to office and home BP (normotension, masked hypertension, white-coat hypertension, and sustained hypertension) and (ii) home BP level (normal BP, high normal BP, grade 1 and 2 hypertension), while the number of home measurement days was increased from 1 to 7. The prognostic accuracy of home BP with an increasing number of home BP measurement days was also assessed by multivariable-adjusted Cox models. RESULTS Agreement in classification between consecutive measurement days indicated near perfect agreement (kappa >= 0.9) after the sixth measurement day for both office and home BP cross-classification (97.8% maintained classification, kappa = 0.97) and home BP level (93.6% maintained classification, kappa = 0.91). Over a follow-up of 8.3 years, 568 participants experienced a cardiovascular event, and the first home BP measurement alone predicted events significantly (P