Pragmatic evaluation of events and benefits of lipid lowering in older adults (PREVENTABLE): Trial design and rationale

Patterns of Statin Therapy Use and Associated Outcomes in Older Veterans Across Kidney Function

BACKGROUND

Despite significant morbidity and mortality related to atherosclerotic cardiovascular disease, to date, most major clinical trials studying the effects of statin therapy have excluded older adults. The objective of this analysis was to evaluate the effect of initiating statin therapy on incident dementia and mortality among individuals 75 years of age or older across the complete spectrum of kidney function.

METHODS

We conducted a retrospective cohort study of 640,191 VA health system patients who turned 75 years of age between 2000 and 2018. Patients on statin therapy received the medication for an average of 6.3 years (standard deviation 4.6 years). The primary outcome of interest included incident dementia diagnosis during the study period. The secondary outcome was all-cause mortality. Cox-proportional hazard analysis was used to evaluate the adjusted association of statin initiation with these outcomes.

RESULTS

There was a higher rate of incident dementia in the No Statin group (4.7%) versus the Statin group (3.2%). Additionally, we observed a 22% all-cause mortality benefit associated with statin therapy. We did not observe a treatment effect with respect to primary or secondary outcomes across varying levels of kidney function.

CONCLUSION

This large cohort study did not reveal an association between the initiation of statin therapy and incident dementia. A survival benefit was seen in statin users compared to non-users. Prospective studies in more diverse populations including older adults will be needed to verify these findings.

Advancing randomized controlled trial methodologies: The place of innovative trial design in eating disorders research

Randomized controlled trials can be used to generate evidence on the efficacy and safety of new treatments in eating disorders research. Many of the trials previously conducted in this area have been deemed to be of low quality, in part due to a number of practical constraints. This article provides an overview of established and more innovative clinical trial designs, accompanied by pertinent examples, to highlight how design choices can enhance flexibility and improve efficiency of both resource allocation and participant involvement. Trial designs include individually randomized, cluster randomized, and designs with randomizations at multiple time points and/or addressing several research questions (master protocol studies). Design features include the use of adaptations and considerations for pragmatic or registry-based trials. The appropriate choice of trial design, together with rigorous trial conduct, reporting and analysis, can establish high-quality evidence to advance knowledge in the field. It is anticipated that this article will provide a broad and contemporary introduction to trial designs and will help researchers make informed trial design choices for improved testing of new interventions in eating disorders. PUBLIC SIGNIFICANCE: There is a paucity of high quality randomized controlled trials that have been conducted in eating disorders, highlighting the need to identify where efficiency gains in trial design may be possible to advance the eating disorder research field. We provide an overview of some key trial designs and features which may offer solutions to practical constraints and increase trial efficiency.

Awaiting the verdict: Statins and the road ahead for primary prevention in older adults

This editorial comments on the article by Orkaby et al. in this issue.

New statin use, mortality, and first cardiovascular events in older US Veterans by frailty status

BACKGROUND

Statins are part of long-term medical regimens for many older adults. Whether frailty modifies the protective relationship between statins, mortality, and major adverse cardiovascular events (MACE) is unknown.

METHODS

This was a retrospective study of US Veterans ≥65, without CVD or prior statin use seen in 2002-2012, followed through 2017. A 31-item frailty index was used. The co-primary endpoint was all-cause mortality or MACE (MI, stroke/TIA, revascularization, or cardiovascular death). Cox proportional hazards models were developed to evaluate the association of statin use with outcomes; propensity score overlap weighting accounted for confounding by indication.

RESULTS

We identified 710,313 Veterans (mean age (SD) 75.3(6.5), 98% male, 89% white); 86,327 (12.1%) were frail. Over mean follow-up of 8 (5) years, there were 48.6 and 72.6 deaths per 1000 person-years (PY) among non-frail statin-users vs nonusers (weighted Incidence Rate Difference (wIRD)/1000 person years (PY), -24.0[95% CI, -24.5 to -23.6]), and 90.4 and 130.4 deaths per 1000PY among frail statin-users vs nonusers (wIRD/1000PY, -40.0[95% CI, -41.8 to -38.2]). There were 51.7 and 60.8 MACE per 1000PY among non-frail statin-users vs nonusers (wIRD/1000PY, -9.1[95% CI, -9.7 to -8.5]), and 88.2 and 102.0 MACE per 1000PY among frail statin-users vs nonusers (wIRD/1000PY, -13.8[95% CI, -16.2 to -11.4]). There were no significant interactions by frailty for statin users vs non-users by either mortality or MACE outcomes, p-interaction 0.770 and 0.319, respectively. Statin use was associated with lower risk of all-cause mortality (HR, 0.61 (0.60-0.61)) and MACE (HR 0.86 (0.85-0.87)).

CONCLUSIONS

New statin use is associated with a lower risk of mortality and MACE, independent of frailty. These findings should be confirmed in a randomized clinical trial.

Cardiovascular Disease in the Older Adult: Where Are We 4 Decades Later?

The 1986 Bethesda Conference on Cardiovascular Disease (CVD) in the Elderly, co-chaired by Drs. Nanette Wenger, Frank Marcus, and Robert O'Rourke, delineated the anticipated social, political, ethical, economic and technological impact of an aging population on the incidence, prevalence, and management of CVD in the US and worldwide. In the ensuing 4 decades, older patients have come to comprise an increasingly large proportion of the CVD population, and there has been an explosion of research in all aspects of CVD affecting older adults. Correspondingly, Geriatric Cardiology is now an established field within cardiovascular medicine. In this communication, we provide a focused update on intersections between CVD and geriatrics from basic science to clinical practice, a review of major advances in diagnosis and treatment of older adults with CVD, and a preview of future research directions in the still evolving field of geriatric cardiology.

Preventive cardiology for the aging population: how can we better design clinical trials of statins?

INTRODUCTION

Older adults form a fast-increasing proportion of the world population. However, gains in increasing quantity of life have not been accompanied by similar gains in quality of life. Older people frequently experience frailty, memory problems, and chronic diseases including cardiovascular disease (CVD) and neurodegenerative diseases. Recent trials have demonstrated the efficacy of anti-hypertensive therapy in older populations but failed to show benefits for aspirin.

AREA COVERED

Statins clearly reduce CVD events in middle-aged populations. There seems to be evidence that the effect is similar in primary prevention older populations based on meta-analyses mainly from sub-groups in large trials, but this becomes less clear with increasing age. However, given differences in drug metabolism and possibly efficacy, competing co-morbidities, their effects on mortality, disability, and dementia in this age group remain to be determined.

EXPERT OPINION

Two large trials are now underway to clarify the role of statin therapy in people aged over 70 years using endpoints of mortality, disability, and neurocognitive endpoints as well as standard cardiovascular disease outcomes. They may provide also provide more evidence on how to approach the over 80 year age group.

Mechanisms of 3-Hydroxyl 3-Methylglutaryl CoA Reductase in Alzheimer's Disease

Alzheimer's disease (AD) is the most common neurodegenerative disease worldwide and has a high incidence in the elderly. Unfortunately, there is no effective therapy for AD owing to its complicated pathogenesis. However, the development of lipid-lowering anti-inflammatory drugs has heralded a new era in the treatment of Alzheimer's disease. Several studies in recent years have shown that lipid metabolic dysregulation and neuroinflammation are associated with the pathogenesis of AD. 3-Hydroxyl 3-methylglutaryl CoA reductase (HMGCR) is a rate-limiting enzyme in cholesterol synthesis that plays a key role in cholesterol metabolism. HMGCR inhibitors, known as statins, have changed from being solely lipid-lowering agents to neuroprotective compounds because of their effects on lipid levels and inflammation. In this review, we first summarize the main regulatory mechanism of HMGCR affecting cholesterol biosynthesis. We also discuss the pathogenesis of AD induced by HMGCR, including disordered lipid metabolism, oxidative stress, inflammation, microglial proliferation, and amyloid-β (Aβ) deposition. Subsequently, we explain the possibility of HMGCR as a potential target for AD treatment. Statins-based AD treatment is an ascent field and currently quite controversial; therefore, we also elaborate on the current application prospects and limitations of statins in AD treatment.

Performance of Cox regression models for composite time-to-event endpoints with component-wise censoring in randomized trials

BACKGROUND

Composite time-to-event endpoints are beneficial for assessing related outcomes jointly in clinical trials, but components of the endpoint may have different censoring mechanisms. For example, in the PRagmatic EValuation of evENTs And Benefits of Lipid-lowering in oldEr adults (PREVENTABLE) trial, the composite outcome contains one endpoint that is right censored (all-cause mortality) and two endpoints that are interval censored (dementia and persistent disability). Although Cox regression is an established method for time-to-event outcomes, it is unclear how models perform under differing component-wise censoring schemes for large clinical trial data. The goal of this article is to conduct a simulation study to investigate the performance of Cox models under different scenarios for composite endpoints with component-wise censoring.

METHODS

We simulated data by varying the strength and direction of the association between treatment and outcome for the two component types, the proportion of events arising from the components of the outcome (right censored and interval censored), and the method for including the interval-censored component in the Cox model (upper value and midpoint of the interval). Under these scenarios, we compared the treatment effect estimate bias, confidence interval coverage, and power.

RESULTS

Based on the simulation study, Cox models generally have adequate power to achieve statistical significance for comparing treatments for composite outcomes with component-wise censoring. In our simulation study, we did not observe substantive bias for scenarios under the null hypothesis or when the treatment has a similar relative effect on each component outcome. Performance was similar regardless of if the upper value or midpoint of the interval-censored part of the composite outcome was used.

CONCLUSION

Cox regression is a suitable method for analysis of clinical trial data with composite time-to-event endpoints subject to different component-wise censoring mechanisms.

Acute Myocardial Infarction and Risk of Cognitive Impairment and Dementia: A Review

Cognitive impairment (CI) shares common cardiovascular risk factors with acute myocardial infarction (AMI), and is increasingly prevalent in our ageing population. Whilst AMI is associated with increased rates of CI, CI remains underreported and infrequently identified in patients with AMI. In this review, we discuss the evidence surrounding AMI and its links to dementia and CI, including pathophysiology, risk factors, management and interventions. Vascular dysregulation plays a major role in CI, with atherosclerosis, platelet activation, microinfarcts and perivascular inflammation resulting in neurovascular unit dysfunction, disordered homeostasis and a dysfunctional neurohormonal response. This subsequently affects perfusion pressure, resulting in enlarged periventricular spaces and hippocampal sclerosis. The increased platelet activation seen in coronary artery disease (CAD) can also result in inflammation and amyloid-β protein deposition which is associated with Alzheimer's Dementia. Post-AMI, reduced blood pressure and reduced left ventricular ejection fraction can cause chronic cerebral hypoperfusion, cerebral infarction and failure of normal circulatory autoregulatory mechanisms. Patients who undergo coronary revascularization (percutaneous coronary intervention or bypass surgery) are at increased risk for post-procedure cognitive impairment, though whether this is related to the intervention itself or underlying cardiovascular risk factors is debated. Mortality rates are higher in dementia patients with AMI, and post-AMI CI is more prevalent in the elderly and in patients with post-AMI heart failure. Medical management (antiplatelet, statin, renin-angiotensin system inhibitors, cardiac rehabilitation) can reduce the risk of post-AMI CI; however, beta-blockers may be associated with functional decline in patients with existing CI. The early identification of those with dementia or CI who present with AMI is important, as subsequent tailoring of management strategies can potentially improve outcomes as well as guide prognosis.