Minimum number of readings necessary for determining long-term visit-to-visit blood pressure variability to predict cardiovascular outcomes in people with diabetes.

Background: People with diabetes often have increased blood pressure (BP) variability because of autonomic dysfunction and arterial stiffness, making it a critical factor in predicting clinical outcomes. We investigated the reproducibility of long-term visit-to-visit BP variability (VVV) and the minimum number of BP readings to reliably determine VVV in people with diabetes.

Methods: This multicenter retrospective study used data from electronic health records of the Korea University Medical Center database. Altogether, 10 475 people with diabetes who had more than nine BP readings during a maximum period of 2 years were identified. This study focused on the coefficient of variation of these readings and their correlation with major adverse cardiovascular events (MACE) over a 3-year follow-up period.

Results: The mean age of the participants was 65.2 years. Of these, 53.2% were men, and 87.4% had hypertension. The mean coefficient of variation of multiple SBP readings that best predicted the 3-year MACE were 8.4, 9.5, 9.0, 9.0, and 9.7 for three, five, seven, nine, and all readings, respectively. Patients with high VVV (coefficient of variation of five SBP readings >9) exhibited a higher incidence of 3-year MACE (10.1%) than those with low VVV (5.4%, P  < 0.001). In the multivariable analysis, high VVV of both SBP and DBP were independently associated with 3-year MACE.

Conclusion: Long-term VVV in the BP is a reproducible and reliable predictor of cardiovascular outcomes in people with diabetes. A minimum of five BP measurements are recommended for effective intraindividual VVV estimation and cardiovascular risk assessment.