Blood pressure in hypertensives—what is the real value?

Sir, To date there is still great uncertainity as to the best way to measure blood pressure (BP). Actually the debate is focused on the reliability of three techniques: self-made (SM), nurse-made (NM) and physician-made (PM) BP readings [ 1 , 2 ]. Recently, we analysed the relationships between SM, NM and PM readings in a cohort of hypertensives consecutively referred to our brand new out-patient clinic from 1 January 2005 to 30 June 2005. Essential hypertensives on wash-out, without comorbidities, owning a sphygmomanometer, have been considered. Our policy in this clinical setting foresees the following steps: At the first visit, serum levels of creatinine, uric acid and glucose are assessed. Moreover, after a detailed training on SM reading followed by the calibration of the sphygmomanometer the patients are invited to record the reading at home just before the following visit, scheduled 1 week later. At the second visit, the patients are approached by the nurse (V.N.) who, after a 5 min sitting rest, takes the NM reading, (average of three determinations within 3 min). Then the physician (L.V.) measures the PM reading in a blinded fashion. During the observation period we screened 182 patients among whom 20 (eight males) met the inclusion criteria. Average (SD) values of age (years) and serum lab parameters (mg/dl) were: age 58.2 (9.4), creatinine 0.96 (0.19) mg/dl, uric acid 4.5 (1.4) mg/dl and glucose 99.1 (13.7) mg/dl. Table 1 reports the systolic, diastolic and mean BP (SBP, DBP and MBP, respectively) values found during the study. For all the components of BP, PM values were significantly higher than the SM and NM values (one-way analysis of variance and Tukey's post-hoc test: P < 0.05). After stratifying the analysis according to median values of the lab parameters, the differences between PM, NM and SM values remained significant only in those patients with serum levels of uric acid >4.2 mg/dl and creatinine >0.97 mg/dl. In the entire cohort of patients, a significant relationship between the MBPs measured by means of PM reading, and the serum uric acid levels ( R = 0.54; P = 0.01) was demonstrated. According to our findings, we suggest that SM and NM readings provide more reliable BP values while PM may suffer from emotional reactions driven by sympathetic activation. The latter is mostly represented in hypertensives with higher serum levels of uric acid and creatinine, confirming, somehow, the suggested close relationship between the clues of renal damage and the sympathetic drive in determining hypertension status and target organ damage [ 3 ]. Moreover, our experience underlines the need to take caution and to evaluate the techniques of BP measurement, in evaluating or planning clinical trials focused on hypertension. Conflict of interest statement . None declared. Values of blood pressure components found with the 3 different techniques Values of blood pressure components found with the 3 different techniques