The effects of ACE inhibitors on cognitive function

The prevention of dementia

OBJECTIVE

Dementia is prevalent in older adults and the population is ageing. Many factors have been associated with dementia and anything that may aid the prevention of dementia is of importance.

METHOD

The literature in this area was evaluated and information relating to the various factors that may impact upon the prevention of dementia is presented below.

RESULTS

Factors that have been associated with a possible increased risk of developing dementia include high blood pressure, (at least in midlife), high body mass index, smoking and possibly diabetes although the evidence is mixed. There is currently no clear evidence with regard to cholesterol and metabolic syndrome although both may be implicated. Having education and maintaining a Mediterranean diet, including vegetable, fruit and fish intake, have been linked to a lower incidence of dementia as has low to moderate alcohol intake. Although care must be taken with the latter given the different characteristics of the studies reporting on alcohol and dementia.

CONCLUSION

It may be that risk and protective factors vary with age, however, in the absence of prophylactic treatment it seems likely that the maintenance of a healthy lifestyle may represent the best option with regard to the prevention of dementia.

A Substudy Protocol of the Hypertension in the Very Elderly Trial Assessing Cognitive Decline and Dementia Incidence (HYVET-COG)

BACKGROUND AND OBJECTIVE

Randomised, controlled trials and population studies have suggested a link between hypertension and the development of dementia (vascular dementia and Alzheimer's disease) although the results are not conclusive. The very elderly are at highest risk for both hypertension and dementia but have been underrepresented in studies to date. The Hypertension in the Very Elderly Trial (HYVET), an international, randomised, double-blind, placebo-controlled trial of antihypertensive medication for those > or =80 years of age, is currently underway. The protocol for the assessment of cognitive decline and detection of incident dementia cases is described in this article. The objective of this protocol is to determine whether treatment of hypertension in this very elderly group affects the incidence of dementia and decline in cognitive function during the period of the HYVET trial.

METHODS

Cognitive function in all HYVET trial participants is assessed at baseline and annually thereafter using the Mini-Mental State Examination (MMSE). An MMSE score that decreases more than three points per year or decreases to <24 prompts further investigation for possible incident dementia. This includes use of the Diagnostic and Statistical Manual-IV criteria, the modified Hachinski scale and CT scanning. In cases where a CT scan cannot be obtained the full Hachinski scale is used. Additional information is provided when available from the clock drawing test and Geriatric Depression Scale. Data are also gathered from all trial participants with regard to education, blood pressure, alcohol use, co-morbidities and concomitant treatments. At the end of the trial, changes in cognitive function and incident dementia cases will be compared in those receiving active treatment (indapamide slow-release +/- perindopril) and those receiving matching placebo.

RESULTS

The protocol has been applied successfully and the data collection phase is underway.

DISCUSSION

Previous population studies have been unable to study antihypertensive use in a controlled manner and randomised, controlled trials suggest a positive or mixed picture regarding an association between use of antihypertensive therapy and reduction in incident cognitive decline and/or dementia. No such trial has yet been performed exclusively in subjects > or =80 years of age with hypertension. The HYVET trial is placebo controlled and while investigating the cardiovascular effect of treatment also assesses cognitive function and quality of life in both the placebo and actively treated arms of the trial. The HYVET cognitive substudy trial (HYVET-COG) design has been successfully applied and the instruments chosen appear to be appropriate, valid and pragmatic.

CONCLUSION

HYVET-COG provides the first opportunity to examine the effect of antihypertensive treatment on incident dementia in a high-risk very elderly population.

Effects of six anti-hypertensive medications on cognitive performance

OBJECTIVE

To describe and compare the effects of six different antihypertensive medications on cognitive performance.

DESIGN

Prospective, randomized, and double-blind with treatment cross-over.

SETTING

University hypertension clinic and neuropsychology laboratory.

PARTICIPANTS

Ninety-eight Caucasian men between 25 and 55 years of age with mild-to-moderate essential hypertension (88 of whom completed the study), and 32 normotensive men with similar socio-demographic characteristics.

INTERVENTIONS

Six-week treatment periods with atenolol, metoprolol, hydrochlorothiazide, methyldopa, enalapril and verapamil, and 2-week placebo baseline and wash-out periods.

MAIN OUTCOME MEASURES

In-depth neuropsychological assessments and several mood questionnaires were completed during placebo (baseline) periods and active treatment periods. Practice effects due to repeated neuropsychological testing were estimated from data collected concurrently in the normotensive participants.

RESULTS

The antihypertensive treatments lowered blood pressure comparably and did not affect mood or anxiety. Small treatment effects were noted in four of seven domains of cognitive performance. Irrespective of medication type, treatment reduced the simple motor speed (P < 0.001), and slowed completion of two tests measuring perceptuo-motor speed and mental flexibility (P </= 0.05). Manual dexterity declined somewhat with metoprolol and methyldopa (P = 0.01). In contrast, all antihypertensive agents favorably affected performance on several tests that require working memory (P < 0.01). Performance on other tests assessing grip strength, learning and memory, attention and executive function was not affected.

CONCLUSION

Short-term treatment with standard antihypertensive medications was associated with some small decrements in psychomotor performance and small improvements in working memory, without notable drug-class differences. Long-term effects await further study.

Atypical cognitive profile in patients with depression after myocardial infarction

BACKGROUND

We evaluated the cognitive profile of 48 patients with major depression following their first myocardial infarction (MI).

METHODS

The cognitive performance of the patients was compared with the performance of 48 non-depressed MI patients and 48 healthy controls.

RESULTS

Depressed MI patients performed slower on a simple cognitive speed related measure compared with non-depressed MI patients and healthy controls. Attention and speed-related aspects of cognitive functioning were not affected. Surprisingly, (depressed) MI patients showed even better performances with respect to memory function.

LIMITATION

No patients with non-MI-related depression were included.

CONCLUSIONS

The cognitive profile of major depression after MI differs from that of non-cardiac-related depressive disorder, as described in the literature. This may reflect a different etiology of post MI depression from non-cardiac-related depression.

Pet Ownership, but Not ACE Inhibitor Therapy, Blunts Home Blood Pressure Responses to Mental Stress

In the present study, we evaluated the effect of a nonevaluative social support intervention (pet ownership) on blood pressure response to mental stress before and during ACE inhibitor therapy. Forty-eight hypertensive individuals participated in an experiment at home and in the physician’s office. Participants were randomized to an experimental group with assignment of pet ownership in addition to lisinopril (20 mg/d) or to a control group with only lisinopril (20 mg/d). On each study day, blood pressure, heart rate, and plasma renin activity were recorded at baseline and after each mental stressor (serial subtraction and speech). Before drug therapy, mean responses to mental stress did not differ significantly between experimental and control groups in heart rate (94 [SD 6.8] versus 93 [6.8] bpm), systolic blood pressure (182 [8.0] versus 181 [8.3] mm Hg), diastolic blood pressure (120 [6.6] versus 119 [7.9] mm Hg), or plasma renin activity (9.4 [0.59] versus 9.3 [0.57] ng · mL −1 · h −1 ). Lisinopril therapy lowered resting blood pressure by ≈35/20 mm Hg in both groups, but responses to mental stress were significantly lower among pet owners relative to those who only received lisinopril ( P <0.0001; heart rate 81 [6.3] versus 91 [6.5] bpm, systolic blood pressure 131 [6.8] versus 141 [7.8] mm Hg, diastolic blood pressure 92 [6.3] versus 100 [6.8] mm Hg, and plasma renin activity 13.9 [0.92] versus 16.1 [0.58] ng · mL −1 · h −1 ). We conclude that ACE inhibitor therapy alone lowers resting blood pressure, whereas increased social support through pet ownership lowers blood pressure response to mental stress.

Quality of life in chronic heart failure: cilazapril and captopril versus placebo. Cilazapril-Captopril Multicentre Group

OBJECTIVE

To measure quality of life (QOL) in patients with mild to moderate heart failure treated with angiotensin converting enzyme (ACE) inhibitors cilazapril or captopril.

DESIGN

Randomised, double blind, placebo controlled, parallel groups trial.

SUBJECTS

367 patients with New York Heart Association (NYHA) heart failure class II (62%), III (36%) or IV (1%).

METHODS

Patients were randomised to receive cilazapril 1 mg daily (n = 191) or captopril 25 mg three times daily (n = 90) for 24 weeks, or placebo for 12 weeks followed by cilazapril 1 mg daily for a further 12 weeks (n = 86). If patients had not responded after four weeks cilazapril was increased to 2.5 mg daily and captopril to 50 mg three times daily. QOL was assessed at baseline, 12, and 24 weeks using the sickness impact profile (SIP), the profile of mood states (POMS), the Mahler index of dyspnoea-fatigue, and a health status index (HSI).

RESULTS

The physical dimension of the SIP averaged 7 units at baseline and improved after 12 weeks by 2.24 units in the cilazapril group, 2.38 units in the captopril group, and 1.51 units in the placebo group. The difference between drug and placebo was therefore 0.73 units (95% CI -0.86 to 2.32) for cilazapril, and 0.87 units (95% CI -0.96 to 2.70) for captopril, with small non-significant effect sizes (a statistical method for estimating the importance of a treatment related change) of 0.12 and 0.14. Similar results were observed for the total POMS and HSI scores. Although QOL improved more on the ACE inhibitors than on placebo, the effect sizes were not significant (< or = 0.26).

CONCLUSIONS

Improvements in QOL in mild to moderate heart failure were small when treated with cilazapril or captopril compared with placebo.