LAUSR

Chronic kidney disease (CKD) and hypertension are strictly interrelated being each one the consequence or the cause of the other [1]. About 80% of subjects with CKD are also hypertensives. On the other hand, a poor blood pressure (BP) control is associated to an increased risk of progression to end-stage renal disease [2] and cardiovascular mortality [3]. In the last years, a wider implementation of out-of-office BP measurements (i.e., ambulatory BP monitoring, ABPM, or home blood pressure monitoring, HBPM) in clinical practice has enabled a more accurate evaluation of real BP load respect to clinic BP [4]. Furthermore, the combined use of office and out-of-office BP allows to identify four different phenotypes even in treated hypertensive subjects (sustained—SUCH, white-coat uncontrolled—WUCH, masked uncontrolled—MUCH and controlled hypertension—CH) with a potential different impact on cardiovascular risk profile, including CKD patients [5]. The data reported by Cupisti et al. [6] on this issue of Internal and Emergency Medicine provide interesting insights on this topic. The authors evaluated changes in BP phenotype at 6 and 12 months as assessed by home and office measurements without variations in drug therapy in a group of 280 non-dialysis CKD patients. They reported a poor reproducibility between these two techniques, since only 38% of patients maintained the same phenotype at 1 year. These results are interesting and deserve some comment. First, HBPM represents a valid and less expensive alternative to ABPM since with a greater implementation of home BP self-measurement many of the advantages provided by ABPM respect to clinic BP could be achieved, such as a greater number of BP readings, the avoidance of white-coat effect and the identification of BP phenotypes. However, to increase the reliability of the information provided by HBPM, the use of standardized protocols of measurements and validated device is a fundamental prerequisite [4]. The inadequate accuracy of HBPM in the study of Cupisti although representing real-life practice might have influenced, at least in part, the variability of BP patterns over months. Second, the reproducibility of BP phenotypes is important in the very short term to verify the accuracy of the techniques used to assess BP and, therefore, to correctly classify subjects in SUCH, WUCH, MUCH and CH. On the other hand, it is not surprising to notice modifications of BP patterns over months, since they are unlikely to reflect a methodological limitation while may represent variations of clinical conditions, even in the absence of changes in pharmacological therapy, especially in CKD patients undergoing progressive loss of renal function. Furthermore, intermediate phenotype such as MUCH and WUCH are expected to be frequently transient conditions between normotension and hypertension and are likely to change over a 1 year time. Accordingly, most of MUCH patients shifted to SUCH over time. Rather, the results reported in this study emphasize the importance of repeated BP measurements over time of both office and out-of-office BP in CKD patients to ascertain BP control and to evaluate residual risk to implement therapeutic measure to improve cardiovascular and renal prognosis.