Objective: To estimate the daytime ambulatory blood pressure monitoring (ABPM) value corresponding to the target office blood pressure (BP; 130/80 mmHg) for diabetic patients and to identify which patients with diabetes may benefit from ABPM.
Methods: A cross-sectional study was conducted with type 1 and type 2 diabetic patients. ABPM (Spacelabs90207) and office BP were measured. Target ABPM was estimated by linear regression equation using daytime ABPM and office BP. Office BP values corresponding to ABPM hypertension were determined by receiver operating characteristic curves.
Results: A total of 554 patients (type 1: n = 200, 36 ± 11 years, diabetes duration 17 ± 9 years; type 2: n = 354; 57 ± 9 years, diabetes duration 10 ± 7 years) were evaluated. Regression equations for SBP and DBP were ABPM = 64.3 + (0.50 office BP) and ABPM = 45.4 + (0.42 office BP), respectively. Daytime ABPM corresponding to the target office BP was 129.3/79 mmHg. Office BP less than 120 for systolic and less than 70 mmHg for diastolic had 90% sensitivity to rule out hypertension diagnosed by ABPM; office BP at least 145 for systolic or at least 90 mmHg for diastolic had 90% specificity to confirm ABPM hypertension. Within these values, 38% of patients were misclassified if only office values were considered.
Conclusion: In type 1 and type 2 diabetes, the recommended upper limit of daytime ABPM is 130/80 mmHg. Patients with office BP at least 120 for systolic or at least 70 for diastolic and less than 145 for systolic and less than 90 mmHg for diastolic should undergo ABPM to correctly determine their BP status.