Withdrawal of antihypertensive drugs in older people

Background: Hypertension is an important risk factor for subsequent cardiovascular events, including ischaemic and haemorrhagic stroke, myocardial infarction, heart failure, chronic kidney disease, cognitive decline and premature death. Overall, the use of antihypertensive medications has led to reduction in cardiovascular disease, morbidity rates and mortality rates. However, the use of antihypertensive medications is also associated with harms, especially in older people, including the development of adverse drug reactions, drug-drug interactions and can contribute to increasing medication-related burden. As such, discontinuation of antihypertensives may be considered and appropriate in some older people.

Objectives: To investigate whether withdrawal of antihypertensive medications is feasible, and evaluate the effects of withdrawal of antihypertensive medications on mortality, cardiovascular outcomes, hypertension and quality of life in older people.

Search methods: The Cochrane Hypertension Information Specialist searched the following databases for randomised controlled trials up to April 2019: the Cochrane Hypertension Specialised Register, CENTRAL (2019, Issue 3), Ovid MEDLINE, Ovid Embase, the WHO International Clinical Trials Registry Platform, and ClinicalTrials.gov. We also conducted reference checking, citation searches and, when appropriate, contacted study authors to identify any additional studies. The searches had no language restrictions.

Selection criteria: We included randomised controlled trials (RCTs) of withdrawal versus continuation of antihypertensive medications used for hypertension or primary prevention of cardiovascular disease in older adults (defined as 50 years and over). Participants were eligible if they lived in the community, residential aged care facilities, or were based in hospital settings. We sought to include trials looking at the complete withdrawal of the antihypertensive medication, and those focusing on a dose reduction of the antihypertensive medicine.

Data collection and analysis: We compared the intervention of discontinuing or reducing antihypertensive medication to usual treatment using mean differences (MD) and 95% confidence intervals (95% CIs) for continuous variables and we used Peto odds ratios (ORs) and 95% CI for binary variables. Our primary outcomes included: mortality, myocardial infarction, development of adverse drug reactions or adverse drug withdrawal reactions. Secondary outcomes included: blood pressure, hospitalisation, stroke, success of withdrawing from antihypertensives, quality of life, and falls. Two authors independently, and in duplicate, conducted all stages of study selection, data extraction and quality assessment.

Main results: Six RCTs met the inclusion criteria and were included in the review (1073 participants). Study duration and follow-up ranged from 4 weeks to 56 weeks. Meta-analysis of studies showed that, in the discontinuation group compared to continuation, the odds for all-cause mortality were 2.08 (95% CI 0.79 to 5.46; low certainty of evidence), for myocardial infarction 1.86 (95% CI 0.19 to 17.98; very low certainty of evidence) and for stroke 1.44 (95% CI 0.25 to 8.35; low certainty of evidence). Blood pressure was higher in the discontinuation group than the continuation group (systolic blood pressure: MD = 9.75 mmHg, 95% CI 7.33 to 12.18; and diastolic blood pressure: MD = 3.5 mmHg, 95% CI 1.82 to 5.18; low certainty of evidence). For the development of adverse events, meta-analysis was not possible; antihypertensive discontinuation did not appear to increase the risk of adverse events and may lead to resolution of adverse drug reactions, although eligible studies had limited reporting of adverse effects of drug withdrawal (very low certainty of evidence). One study reported hospitalisation with an odds ratio of 0.83 for discontinuation compared to continuation (95% CI 0.33 to 2.10; low certainty of evidence). No studies were identified which reported falls. Between 10.5% and 33.3% of participants in the discontinuation group compared to 9% to 15% in the continuation group experienced raised blood pressure or other clinical criteria (as pre-defined by the studies) that would require restarting of therapy/removal from the study. The sources of bias included selective reporting (reporting bias), lack of blinding of outcome assessment (detection bias), incomplete outcome data (attrition bias), and lack of blinding of participants and personnel (performance bias).

Authors' conclusions: There is no evidence of an effect of discontinuing compared with continuing antihypertensives used for hypertension or primary prevention of cardiovascular disease in older adults on all-cause mortality and myocardial infarction. The evidence was low to very low certainty mainly due to small studies and low event rates. These limitations mean that we cannot make any firm conclusions about the effect of deprescribing antihypertensives on these outcomes. Future research should focus on populations with the greatest uncertainty of the benefit:risk ratio for use of antihypertensive medications, such as those with frailty, older age groups and those taking polypharmacy, and measure clinically important outcomes such as falls, quality of life and adverse drug events.