Statins for the primary prevention of cardiovascular diseases: An Asian real-world perspective

There are relatively few reliable data on statins for the primary prevention of atherosclerotic cardiovascular disease (ASCVD) among the elderly, and even less among the Asian population, as reported by Lin et al. [ ]. Despite the substantial decline in the burden of ASCVDs during the past decades, elderly and women are still often under-represented in cardiovascular randomized clinical trials (RCTs), implying that current recommendations for the management of ASCVD do not adequately address these populations [ , ]. In addition, several real-world studies have assessed statins for primary prevention among the Western older population, but results seem to be inconsistent and are not generalizable to an Asian population. From the metanalyses of both RCTs and observational studies investigating the effectiveness of statins for primary prevention using age-specific outcome data, results are encouraging, but still characterized by methodological limits [ , ]. Current international guidelines [ , , , , ] recommend statin initiation in high-risk primary prevention conditions when a previous ASCVD event is absent, but a gap between RCTs and real-world practice still exists. In this context of uncertainty regarding the benefit/risk profile of statins used in the primary prevention of the elderly, Lin and colleagues' [ ] aimed to assess the effectiveness of statins for the primary prevention of ASCVD in an Asian older population. They carried out a retrospective study based on the record linkage of different national Taiwanese databases, and identified the population aged 65 and older without a history of ASCVD, from 2008 and 2015. It is worth noticing that women accounted for the 64% of the total sample, documenting once again how large is the gap between RCTs and the real clinical practice in terms of demographics of the study populations. At a median follow-up of 4.8 years, Lin et al. [ ] found that statin use was associated with a significant reduction of major adverse cardiac events (MACE) and broadly-defined MACE (−25%), and of all-cause mortality (−21%) without any heterogeneity of effect observed across the subgroups stratified by age, sex, diabetes status and baseline low-density lipoprotein-cholesterol (LDL-C) levels. The Lin's study has some strengths [ ]. First, it originates from the record linkage of several national databases (i.e., hospital, insurance, registries of catastrophic illness and death causes), which allowed to analyze laboratory data, social history and other in-hospital data, comorbidities, co-medications and causes of death. This allowed the identification of a large sample of patients that was truly representative of the population at high risk for ASCVD (i.e., high rate of females and high LDL-C levels [ , , ]), and to overcome some limitations of the use of only administrative data (e.g., adherence to drugs privately purchased, and the effect of time-varying LDL-C levels). Second, the sample was analyzed within a long observation period (from 2008 to 2017), by applying models (i.e., propensity score and marginal structure) to adjust for potential confounding variables, especially the annual LDL-C levels. Moreover, the intrinsic weakness of the observational nature of the study was mitigated by several sensitivity analyses, which confirmed the main messages of the primary analyses. The study presents also some limitations related to the observational nature and secondary use of the databases (i.e., absence of some clinical variables, including safety data, and sample size insufficient to stratify by several CVD risk factors), and to the exclusive Asian origin of the population, which prevents from generalizing the results. Nevertheless, the latter can be considered, at the same time, a strength, due to the very poor literature about the Asian population.