(ASPOT48) Discontinuation of preventative treatments in older people with complex health needs: self-controlled case series analyses of preventable cardiovascular events

Background: There is a lack of evidence and inconsistent recommendations on the continued use of statins and antihypertensives in old people with limited life expectancy.

Objectives: To assess the effect of discontinuation of antihypertensives and statins on the risk of cardiovascular events in older patients with complex health needs.

Methods:

Design: Self-controlled case series (SCCS).
Setting: UK primary care electronic health records.
Participants: Patients aged >65 years registered in CPRD GOLD for ≥1 year before study start (01/01/2010), who in 2009 had a non-elective hospitalisation, were frail or received poly-pharmaceutical treatment, comprised the source population. Of those, all people who started treatment with antihypertensives or statins after study start and had a record of a myocardial infarction (MI) or stroke during follow-up were included, respectively.
Exposure: Discontinuation of antihypertensives and statins, defined as a treatment gap of >90days.
Main outcome measures and analyses: Incidence rate ratios (IRR) were calculated separately for MI and stroke, comparing event rates for the respective outcomes during treatment vs. post-discontinuation periods. SCCS were conducted separately for statins and antihypertensives, and adjusted using 5-year age bands. Assumptions of the SCCS method were tested, and sensitivity analyses censoring follow-up in case of treatment restart were conducted.

Results: Of the 198,039 people included in the source population, 738 and 669 persons contributed to the analysis of antihypertensive therapy discontinuation and MI and stroke risk, while 1,408 and 1,361 persons were included for the SCCS of statin discontinuation and MI and stroke risk, respectively.
Risk of MI was substantially increased following discontinuation of antihypertensives (IRR 2.60 [95%CI 1.56 to 4.33]) and statins (IRR 1.75 [1.16 to 2.62]). However, no significant association for discontinuation of antihypertensive therapy or statins and increased stroke risk was seen (IRR 1.31 [0.85 to 2.01] and IRR 1.44 [0.97 to 2.15]). Results from sensitivity analyses showed slightly higher IRR for all analyses.

Conclusions: Our study showed risks associated with discontinuing antihypertensive treatment. Further research focussing on the risk-benefit of these treatments for older adults with complex health needs is needed.