Notwithstanding all advantages, HBPM also has some limitations. First of all, the HBPM technique, like ABPM, is less suitable in subjects with large arm sizes for whom no appropriate cuff in available, in those with an irregular pulse, or when there is reason to suspect vascular stiffening. Indeed, almost all validated HBPM devices employ the oscillometric technique, which may yield results that differ substantially from BP readings taken with a sphygmomanometer. This is particularly true in elderly patients and those with diabetes (77- 78). Second, ABPM is still superior for measuring BP at predetermined times without any influence of the patient, to record BP during daily routine or during the night and to ascertain whether a drug is effective during the early morning surge. However, because HBPM is less expensive and less inconvenient for the patient, it can serve as a reliable addition to OBPM, although the latter should not be abandoned yet (23,79). Moreover, there is already an HBPM device available that is able to measure BP during sleep at predetermined times (80). Third, HBPM should not be recommended for subjects with pre-eclampsia because both the auscultatory and oscillometric methods have shown to be inappropriate in this situation (81). Fourth, it should be realized that certain aspects of HBPM need further research, especially because the recently published Treatment of hypertension based on Home or Office blood Pressure (THOP) trial showed that adjustment of antihypertensive treatment based on HBPM instead of OBPM led to less intensive drug treatment but also to less BP control (82). Therefore, until this subject has been investigated further, treatment decisions based on HBPM alone should be taken cautiously. Finally, because regular subjects require at least 20 min of instruction (28) before understanding the procedure, HBPM may not be appropriate for every patient because of its complexity. Additionally, HBPM should also be discouraged when it causes anxiety or induces self-modification of treatment.