Meta-Analysis of Usefulness of Treatment of Hypercholesterolemia With Statins for Primary Prevention in Patients Older Than 75 Years

Treating Hypercholesterolemia in Older Adults for Primary Prevention of Cardiovascular Events

As the population ages, the demographic of adults aged 75 years and older in the U.S. is projected to grow to 45 million by 2050. Hypercholesterolemia is directly linked to atherosclerotic cardiovascular disease (ASCVD), which remains the leading cause of death in older adults. However, primary prevention of ASCVD through lipid-lowering agents remains unclear among older adults owing to limited involvement of older adults in current trials, lack of dedicated trials, and evidence primarily derived from secondary and retrospective analyses. Therefore, this article aims to (1) review key updates from the latest guidelines on treatment of hypercholesterolemia in older adults, (2) highlight limitations of the current ASCVD risk scores in the geriatric population, (3) present outcomes from key studies on the use of lipid-lowering agents and associated side effects, including a brief review of novel agents such as bempedoic acid, although very few adults over age 75 were included in these trial, and (4) finally, highlight upcoming dedicated trials of statins in older adults for the primary prevention of important geriatric outcomes as well as ASCVD.

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.

Development, validation, and visualization of a web-based nomogram to predict 5-year mortality risk in older adults with hypertension

Background

Hypertension-related mortality has been increasing in older adults, resulting in serious burden to society and individual. However, how to identify older adults with hypertension at high-risk mortality remains a great challenge. The purpose of this study is to develop and validate the prediction nomogram for 5-year all-cause mortality in older adults with hypertension.

Methods

Data were extracted from National Health and Nutrition Examination Survey (NHANES). We recruited 2691 participants aged 65 years and over with hypertension in the NHANES 1999-2006 cycles (training cohort) and 1737 participants in the NHANES 2007-2010 cycles (validation cohort). The cohorts were selected to provide at least 5 years follow-up for evaluating all-cause mortality by linking National Death Index through December 31, 2015. We developed a web-based dynamic nomogram for predicting 5-year risk of all-cause mortality based on a logistic regression model in training cohort. We conducted internal validation by 1000 bootstrapping resamples and external validation in validation cohort. The discrimination and calibration of nomogram were evaluated using concordance index (C-index) and calibration curves.

Results

The final model included eleven independent predictors: age, sex, diabetes, cardiovascular disease, body mass index, smoking, lipid-lowering drugs, systolic blood pressure, hemoglobin, albumin, and blood urea nitrogen. The C-index of model in training and validation cohort were 0.759 (bootstrap-corrected C-index 0.750) and 0.740, respectively. The calibration curves also indicated that the model had satisfactory consistence in two cohorts. A web-based nomogram was established (https://hrzhang1993.shinyapps.io/dynnomapp).

Conclusions

The novel developed nomogram is a useful tool to accurately predict 5-year all-cause mortality in older adults with hypertension, and can provide valuable information to make individualized intervention.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-022-03087-3.

Association of statin use in older people primary prevention group with risk of cardiovascular events and mortality: a systematic review and meta-analysis of observational studies

BACKGROUND

Current evidence from randomized controlled trials on statins for primary prevention of cardiovascular disease (CVD) in older people, especially those aged > 75 years, is still lacking. We conducted a systematic review and meta-analysis of observational studies to extend the current evidence about the association of statin use in older people primary prevention group with risk of CVD and mortality.

METHODS

PubMed, Scopus, and Embase were searched from inception until March 18, 2021. We included observational studies (cohort or nested case-control) that compared statin use vs non-use for primary prevention of CVD in older people aged ≥ 65 years; provided that each of them reported the risk estimate on at least one of the following primary outcomes: all cause-mortality, CVD death, myocardial infarction (MI), and stroke. Risk estimates of each relevant outcome were pooled as a hazard ratio (HR) with a 95% confidence interval (CI) using the random-effects meta-analysis model. The quality of the evidence was rated using the GRADE approach.

RESULTS

Ten observational studies (9 cohorts and one case-control study; n = 815,667) fulfilled our criteria. The overall combined estimate suggested that statin therapy was associated with a significantly lower risk of all-cause mortality (HR: 0.86 [95% CI 0.79 to 0.93]), CVD death (HR: 0.80 [95% CI 0.78 to 0.81]), and stroke (HR: 0.85 [95% CI 0.76 to 0.94]) and a non-significant association with risk of MI (HR 0.74 [95% CI 0.53 to 1.02]). The beneficial association of statins with the risk of all-cause mortality remained significant even at higher ages (> 75 years old; HR 0.88 [95% CI 0.81 to 0.96]) and in both men (HR: 0.75 [95% CI: 0.74 to 0.76]) and women (HR 0.85 [95% CI 0.72 to 0.99]). However, this association with the risk of all-cause mortality remained significant only in those with diabetes mellitus (DM) (HR 0.82 [95% CI 0.68 to 0.98]) but not in those without DM. The level of evidence of all the primary outcomes was rated as "very low."

CONCLUSIONS

Statin therapy in older people (aged ≥ 65 years) without CVD was associated with a 14%, 20%, and 15% lower risk of all-cause mortality, CVD death, and stroke, respectively. The beneficial association with the risk of all-cause mortality remained significant even at higher ages (> 75 years old), in both men and women, and in individuals with DM, but not in those without DM. These observational findings support the need for trials to test the benefits of statins in those above 75 years of age.

Limitations of Randomized Clinical Trials

Randomized clinical trials are essential for determining the efficacy of interventions, but have limitations. The types of limitations discussed in this review may be grouped in 11 categories including incorrect statistical inference, low internal or external validity, misinterpretation of the difference between frequentist and Bayesian statistical approaches, publication bias, that healthy persons with a given condition participate in clinical trials although they are not representative of the population as a whole, the rather short duration (3 to 5 years) that does not give correct estimates of the lifetime effects of the interventions or the legacy effect when participants who receive active therapy derive residual benefit after the end of the study when all participants receive active medication and the tension between the generalizability of the evidence versus the reliability of the findings of different types of clinical trials and the difficulty in applying the findings of randomized clinical trials to individual patients. These limitations are described and illustrated by examples and figures from the literature. In conclusion, this review will be useful to clinical trialists, clinical trial participants and regulatory agents.