Diabetic patients are at a higher risk for cardiovascular events. It is important to control dyslipidemia and blood pressure (BP) as well as to control blood glucose for the prevention of cardiovascular events. In addition, home BP (HBP) measurement has been found to have a stronger relation with target organ damage and with a risk of cardiovascular events when compared with clinic BP measurement (1–3). Therefore, the significance of HBP measurement has been widely recognized. However, there are no studies evaluating the reliability of HBP measurement in patients with type 2 diabetes. The aim of this study was to investigate the clinical characteristics in patients with the lowest quartile (quartile 1) of concordance rate between self-reported and stored HBP measurements.
HBP measurements were performed in 280 patients with type 2 diabetes, regardless of the presence of hypertension, who had regularly attended the diabetes outpatient clinic at Hospital of Kyoto Prefectural University of Medicine between May 2011 and July 2012. HBP measurements were performed using an automatic device, HEM-7080IC (Omron Healthcare Co. Ltd, Kyoto, Japan), which is capable of electronically storing BP measurements. All patients used this oscillometer for the first time and were unaware that the HBP monitor electronically stored the BP results. They were instructed to perform triplicate morning and evening measurements for 14 consecutive days. We examined the concordant rate between the logbook data, which were written by patients in their logbook, and the memory data, which were retrieved from the memory of the electronic BP device. Then we divided the patients into the upper quartiles (quartiles 2–4) and the lowest quartile (quartile 1) of concordance rate of HBP and examined the characteristics of quartile 1.
The concordance rate between BP from memory and from logbook was 78.6%. The concordance rate of quartile 1 was less than 67%. Clinical characteristics of patients are shown in Table 1. Age, duration of diabetes, BMI, hemoglobin A1c, and frequencies of diabetes complications were not different between groups. Morning systolic BP was higher in quartile 1 than that in quartiles 2–4, although it did not reach statistical significance. SD of morning systolic BP, which is an index of variability of BP, was greater in quartile 1 than in quartiles 2–4. Low concordance rate of HBP was associated more with variability of BP than with BP level in HBP measurement. A limitation of this study is that the numbers of patients were relatively small, because we chose the patients who did not know the storage function of BP monitor. However, this is the first study to investigate the clinical characteristics in patients with the lowest quartile (quartile 1) of concordance rate between self-reported and stored HBP measurements. We should instruct patients to record the HBP measurement correctly, because false reporting of uncontrolled pressures may misguide physicians in the optimal medical treatment of their patients.
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Acknowledgments. The authors thank Naoko Higo, Machiko Hasegawa, and Terumi Kaneko (Kyoto Prefectural University of Medicine) for teaching patients how to measure their BP; Sayoko Horibe, Hiroko Kawamura, and Sanae Utena (Kyoto Prefectural University of Medicine) for their secretarial assistance; and Akane Miki (Kyoto Prefectural University) for her enormous help of data handling.
Duality of Interest. No potential conflicts of interest relevant to this article were reported.
Author Contributions. S.Mat. researched data and wrote the manuscript. M.F. and E.U. contributed to discussion and reviewed the manuscript. M.H. researched data and contributed to discussion. M.K., M.Y., and G.H. contributed to discussion. K.Ma., T.F., K.Mi., and S.Maj. researched data. N.N. reviewed and edited the manuscript. M.F. is the guarantor of this work and, as such, had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
