Characterizing blood pressure control in individuals with Type 2 diabetes: The relationship between clinic and self-monitored blood pressure

Aims: To determine the relationship between blood pressure (BP) measurement in the clinic and self-monitored blood pressure (SMBP); and to evaluate the accuracy of self-reported data in patients with Type 2 diabetes treated intensively for hypertension. Methods: Seventy subjects had baseline and 1-week follow-up clinic BP measured using an Omron 907® automated device. During a contemporaneous 14-day period these subjects measured their BP at least four times each day using an Omron IC® semiautomatic portable monitor which, unknown to them, contained an onboard memory capable of storing BP with corresponding time and date. Results: There was no significant difference between mean clinic and mean self-monitored BP. Correlations between clinic BP and SMBP were r = 0.61 (P < 0.0001) for systolic BP and r = 0.69 (P < 0.0001) for diastolic BP. Clinic BP classified 56 subjects as uncontrolled hypertension (BP ≥ 130/80 mmHg, adjusted for diabetes) and 14 subjects as controlled hypertension. Using World Health Organization-International Society of Hypertension criteria for SMBP (≥ 125/75 mmHg), 55 cases of clinic classified uncontrolled hypertension were confirmed, resulting in 98% sensitivity. Clinic and SMBP agreed in one case of controlled hypertension, resulting in 7% specificity. For all subjects, the median percent of values exceeding SMBP criteria for controlled hypertension was systolic 92% and diastolic 70%. Self-reporting precision averaged 89 ± 10% (range 45-100%); under-reporting was 25 ± 16% (ranging from 0 to 56%) and over-reporting was 12 ± 15% (ranging from 0 to 46%). The overall logbook mean was not significantly different from the downloaded data from the Omron IC® monitors. Conclusions: SMBP was able to identify 13 patients with uncontrolled hypertension who, by clinic BP measurement, had been classified as controlled. Diabet. Med. 20, (2003).