Ambulatory blood pressure monitoring: is it necessary for the routine assessment of hypertension in people with diabetes?

Aims: The British Hypertension Society (BHS) has recommended that, for people with diabetes, the target 'clinic' blood pressure should be < 140/80 mmHg. Ambulatory monitoring of blood pressure (ABPM) is used widely in the assessment of hypertension and the BHS has recommended that the target 'awake' ambulatory blood pressure for people with diabetes should be < 130/75 mmHg. The purpose of the present study was to determine the utility of ABPM in the assessment of hypertension in patients with diabetes, over and above a careful 'clinic' measurement of blood pressure.
Methods: The records of 540 patients with diabetes who underwent ABPM (using SpaceLabs monitors) were retrospectively analysed. With respect to current BHS recommendations, the positive and negative predictive values of 'clinic' blood pressure (measured by trained nurses using mercury sphygmomanometers) on 'awake' ambulatory blood pressure (ABP) were calculated.
Results: The positive predictive value of the 'clinic' BP, its ability to detect patients whose ABP was above BHS targets, was 99%. The negative predictive value of 'clinic' blood pressure was 27%.
Conclusions: With regard to current BHS guidelines, ABPM is generally unnecessary in the assessment of hypertension in patients with diabetes, provided careful 'clinic' measurements of blood pressure are made.