Elderly patients treated with antihypertensive drugs are at lower risk for developing dementia, a new case-control study shows. Federico Rea, PhD, of the University of Milano-Bicocca, Milan, reported these results in a manuscript published Monday online and in the April 2 issue of the Journal of the American College of Cardiology. Patients with hypertension in middle life or older age are at greater risk for developing dementia due to the deterioration of brain matter from elevated blood pressure (BP). Antihypertensive treatment may reduce this risk or delay cognitive impairment. The investigators in this case-control study examined the effects of antihypertensive drugs on the risk of dementia in patients aged 65 years or older. A total of 215,547 patients who began taking antihypertensive drugs between 2009 and 2012 in Lombardy, Italy, were included in this study. A total of 13,812 patients (mean age=77.5 years, 60% female) who developed dementia or Alzheimer’s disease during follow-up to 2019 were the included cases. Sex, age and clinical status were matched in five control subjects per case. Drug therapy exposure was measured using the time during follow-up when the patients took antihypertensive drugs. An inverse association was observed between exposure to treatment and the risk of dementia. High (24%, 95% confidence interval [CI]=19% to 28%), intermediate (12%, 95% CI=6% to 7%) and low (2%, 95% CI=-4% to 7%) exposure to antihypertensive treatment showed greater risk reductions compared with very low exposure. Very old and frail patients also experienced this reduced risk (≥85 years old and patients who had high 1-year mortality risk). The authors acknowledged a few limitations to their study. First, exposure to the antihypertensive drugs was measured based on the assumption that patients took their prescribed drugs. Dementia may have been present in some patients prior to diagnosis as well. The study design includes only a fraction of the patient population, excluding a large number of patients who had been treated with antihypertensive for long periods of time. Finally, because the database does not include BP information, the authors cannot determine at which BP levels the lower risk of dementia was more or less pronounced. The investigators concluded that exposure to hypertensive drugs reduces the risk of dementia development in older patients. In an accompanying editorial, Clinton B. Wright, MD, MS, and Marco Egle, PhD, of the National Institute of Neurological Disorders and Stroke, discussed former studies on the effects of hypertension on dementia and the contributions of the present paper. They wrote that the results are “exciting” but added that there are still many unanswered questions. One of these questions, they said, is that the assumption that prescription can be used as a proxy for adherence to the prescribed regimen, has not been proven to be reliable. The editorialists pointed out that previous estimates show suboptimal adherence to be >50%, which would substantially reduce the effectiveness of the medication and, therefore, BP control. “Although recent U.S. guidelines state that controlling BP is ‘reasonable’ to prevent dementia, knowledge gaps exist about the risks associated with different types of hypertension. This is worth investigating,” they wrote, adding that future studies need to investigate this association in more diverse populations. Sources: Rea F, Corrao G, Mancia G. Risk of Dementia During Antihypertensive Drug Therapy in the Elderly. J Am Coll Cardiol. 2024;83:1194-1203. Wright CB, Egle M. Rethinking Blood Pressure Treatment and Dementia Risk in Older Adults: Is Adherence the Holy Grail? J Am Coll Cardiol. 2024;83:1204-1206. Image Credit: asadykov – stock.adobe.com