Commentary on ‘Is Mini‐Mental Score Examination Scoring a New Predictor of Uncontrolled Hypertension?’

The work of Dr Sayed and coworkers published in this issue of The Journal of Clinical Hypertension examines the utility of the Mini‐Mental Score Examination (MMSE) as a predictor of uncontrolled hypertension. The results show a clear association between cognitive status measured by MMSE and high blood pressure (BP) according to ambulatory BP monitoring (ABPM). This association was not found for office BP. The authors conclude that the MMSE may be useful in identifying patients with uncontrolled hypertension.

The relationship between BP and cognitive decline has more evidence every day. It has been reported that hypertension in middle age is associated with greater cognitive impairment (memory loss, executive function, and processing speed) after 6 to 12 years. Patients with untreated or uncontrolled hypertension present further deterioration.1, 2

There is also a direct relationship between white matter lesions (WMLs) detected by neuroimaging and office BP3, 4 and ABPM,5 specially regarding the systolic component. Again, the results show more WMLs in patients with treated uncontrolled hypertension and especially in patients with untreated uncontrolled hypertension. In parallel, faster progression in WML volumes was associated with a stronger decrease in overall cognitive performances at follow‐up after 4 years.4

Despite these data, most meta‐analyses show no significant beneficial effect of antihypertensive treatment on cognitive decline.6, 7 There are many reasons for these results. First, cognitive impairment was not the primary endpoint studied. Second, the instrument used for the detection of cognitive impairment was the MMSE, the limitations of which are well‐known (ie, the lack of sensitivity in the early stages of cognitive impairment, particularly executive dysfunction of the frontal lobe, which is an early feature of vascular disease, or the involvement of various confounding variables, such as educational level). Finally, not all studies used simultaneous neuroimaging.

The approach of the work of Dr Sayed and coworkers is original. Using a sample of hypertensive patients close to 70 years and with 1.5 and 30 years of disease progression, the authors conclude that cognitive impairment is a predictor of uncontrolled ambulatory BP despite normal office BP. In fact, office BP has no association with the presence of cognitive impairment or WML.

The uncontrolled ambulatory or out‐of‐office BP is a clinical situation that is attracting growing interest because of the association with an increased presence of subclinical cardiovascular disease, with cardiovascular morbidity and mortality, and with increased total mortality.8, 9 Importantly, home BP measurement (HBPM) has also shown utility in the diagnosis and monitoring of patients with uncontrolled out‐of‐office BP.10 In a situation of regular clinical monitoring of the patient, despite antihypertensive treatment and apparent good BP control in the office, uncontrolled hypertension may be suspected by the appearance of new forms of subclinical vascular disease or the progression of existing lesions. In these cases, ABPM or HBPM are helpful to diagnose and properly treat uncontrolled hypertension. The study results show that cognitive decline is evident in patients with 24‐hour elevated ambulatory systolic BP and nighttime systolic BP, even when daytime systolic BP is within normal limits. Under these conditions it is difficult to detect uncontrolled hypertension, especially in hypertensive patients with occasional monitoring of hypertension or with infrequent office BP measurements. This is likely a common problem in developing countries. It is in this context that the MMSE can provide information to select hypertensive patients in whom ABPM or HBPM should be performed.

The authors did not present data on the educational level of the patients included in the study. As mentioned above, the MMSE is biased by educational level. Although available data of neuroimaging to quantify WMLs and the correlation with the MMSE seem correct, one cannot rule out a bias. In this sense, the use of a brief cognitive instrument with less influence of educational level, such as the clock‐drawing test, would have been more appropriate.11 It would have been interesting to have included not only the educational level of the patients in the study but also their BP and antihypertensive treatment prior to inclusion, which, in cases of greater cognitive impairment, may have started up to 20 to 28 years before. Therefore, the results may not be applicable to the general hypertensive population. It is possible, however, to consider a group of hypertensive patients (65 years and older, with normal or almost normal office BP, diagnosed with hypertension more than 12 years ago) in whom the administration of the MMSE may help in identifying uncontrolled out‐of‐office BP and who are candidates for ABPM or HBPM. In any case, the MMSE, a simple and brief instrument, may also be useful in hypertensive patients to assess the long‐standing involvement of small cerebral vessels. However, it should be noted that there may be many other reasons unrelated to hypertension for cognitive impairment in the community.

A brief cognitive instrument to measure executive function, which appears to be linked to early brain microcirculation problems, may offer new perspectives in the comprehensive assessment of all hypertensive patients. The presence of cognitive impairment or executive dysfunction may indicate uncontrolled hypertension, and measures for better diagnosis and BP control, including the ABPM or HBPM, should then be adopted.