Ambulatory Blood PressureMonitoring in the Diagnosis andManagement of

Hypertension (HTN) is a major riskfactor for cardiovascular morbidityand mortality, especially in patients with diabetes mellitus (1). The classic def-inition of HTN is based on office blood pressure (BP) measurements, and most data relating HTN to cardiovascular mor-bidity andmortality are derived fromoffice measurements (2). Yet, the measurements in the office may not reflect the true BP levels. They may be elevated when the true BP is normal (white coat effect), or they may be normal when the true BP is elevated (masked HTN). Office mea-surements also do not reflect the diurnal variation and nocturnal BP levels. Twenty-four-hour ambulatory BP monitoring (ABPM) is a precise method to quantify BP levels and diagnose HTN. Recent studies showed that 24-h ABPM is more accurate than office BP measurements in predicting cardiovascular morbidity and mortality (3–6). The present review will summarize the advantages of 24-h ABPM over office measurements and will recommend when and how to use 24-h ABPM in the diagnosis of HTN in diabetic patients. Ambulatory BP measurements The use of 24-h ABPM was introduced in the late 1970s. In the beginning, the devices were large, heavy, and cumber-some, but today the devices are light-weight and nearly all of them use an oscillometric measurement method to compute BP levels. Thismethod eliminates observer bias and provides information on BP levels and heart rate throughout the day. The large numbers of readings ob-tained during the patient’s daily activities provide a superior assessment of the true BP and can be used for the diagnosis of HTN. Additionally, 24-h ABPM provides information on BP variability, circadian changes, and the effects of environmental and emotional conditions on BP levels. Several studies that compared ABPM with intra-arterial measurements and mercury column sphygmomanometers demonstrated the accuracy of ABPM (7). However, since many new devices have appeared in the market, it is necessary to validate each device according the criteria proposed by the national committees. It is recommended to perform the 24-h monitoring on a typical working week-day and to obtain a diary or log of activ-ities, wake and sleep times, time of medication administration, meals, and any occurrence of symptoms. Excessive heavy physical activity during measure-ments should be avoided