The Lancet AUGUST 24, 2019

Effectiveness of polypill for primary and secondary prevention of cardiovascular diseases (PolyIran): a pragmatic, cluster-randomised trial

Roshandel G, Khodadost M, Poustchi H, Hemveera C, Khoshnia M, et al.

Bottom Line

In this large-scale, pragmatic, cluster-randomized trial, a once-daily polypill containing aspirin, a statin, and two antihypertensives significantly reduced the risk of major cardiovascular events in adults over age 50 compared to minimal care.

Key Findings

1. The polypill significantly reduced the risk of major cardiovascular events (MCVE) compared to minimal care, with 202 events (5.9%) occurring in the polypill group versus 301 events (8.8%) in the minimal care group (adjusted hazard ratio [HR] 0.66; 95% CI 0.55–0.80).

2. In a subgroup analysis, participants in the polypill group with high medication adherence (≥70%) showed an even greater reduction in risk, with an adjusted HR of 0.43 (95% CI 0.33–0.55).

3. The observed cardiovascular benefit was achieved despite modest blood pressure reductions, suggesting the mechanism may be significantly driven by the antiplatelet and cholesterol-lowering components.

4. Adverse event rates were similar between the intervention and control groups, with no significant difference in intracranial hemorrhage or upper gastrointestinal bleeding.

Study Design

Design

RCT

Open-Label

Sample

6,838

Patients

Duration

60 mo

Median

Setting

Rural Iran

Population Adults aged 50–75 years from the Golestan province, including both primary and secondary cardiovascular disease prevention candidates.

Intervention A once-daily polypill (aspirin 81 mg, atorvastatin 20 mg, hydrochlorothiazide 12.5 mg, and either enalapril 5 mg or valsartan 40 mg) combined with non-pharmacological lifestyle interventions.

Comparator Minimal care group receiving only non-pharmacological lifestyle interventions (healthy diet, exercise, weight control, and abstinence from smoking and opium).

Outcome Composite of major cardiovascular events, including hospitalization for acute coronary syndrome, fatal myocardial infarction, sudden death, heart failure, coronary artery revascularization, and non-fatal/fatal stroke.

Study Limitations

• The study was a pragmatic, open-label trial, which could introduce bias, although the primary outcome was centrally assessed by investigators masked to the allocation status.

• The trial was nested within a pre-existing cohort study, which may limit generalizability to populations outside of the specific demographic and infrastructure context of rural Iran.

• Participants at elevated risk for bleeding were excluded, which may underestimate the risks of aspirin therapy in a real-world, broader population.

• The trial did not compare the polypill against standard-of-care monotherapy, but rather against a minimal care control group supplemented with lifestyle advice.

Clinical Significance

This trial provides robust evidence that a low-cost, fixed-dose polypill strategy can effectively reduce cardiovascular morbidity in low- and middle-income countries, offering a scalable approach to address the global burden of cardiovascular disease, especially in settings with limited resources for individual cardiovascular risk factor management.

Historical Context

First proposed over 15 years ago, the 'polypill' concept aimed to simplify cardiovascular prevention by combining aspirin, statins, and antihypertensives into a single dose to improve adherence. While prior smaller studies established the feasibility and safety of such combinations, PolyIran is recognized as the first large-scale, long-term, pragmatic trial to demonstrate hard clinical cardiovascular outcomes.

Guided Discussion

High-yield insights from every perspective

Med Student

Medical Student

The PolyIran polypill contains aspirin, atorvastatin, hydrochlorothiazide, and an ACE inhibitor or ARB. What is the pharmacological rationale for combining these four specific classes of drugs for cardiovascular prevention?

Key Response

This combination targets the three primary pillars of atherosclerotic cardiovascular disease (ASCVD) pathogenesis: dyslipidemia (statin), hypertension (diuretics and ACEi/ARB), and thrombus formation (aspirin). By addressing multiple risk factors simultaneously, the polypill aims to achieve a synergistic reduction in the risk of major adverse cardiovascular events (MACE).

Resident

The PolyIran trial was a pragmatic study comparing a polypill to 'minimal care.' In a patient with multiple cardiovascular risk factors, how does the fixed-dose polypill strategy compare to the conventional 'treat-to-target' approach regarding adherence and clinical outcomes?

Key Response

While 'treat-to-target' allows for precision medicine, the PolyIran trial demonstrated that a simplified, fixed-dose 'one-size-fits-all' strategy significantly improves long-term adherence. In this study, the polypill reduced MACE by 34%, suggesting that for many patients, the benefit of consistent, simplified therapy outweighs the theoretical benefit of finely-tuned individual dosing that is often not achieved in real-world practice.

Fellow

How do the results of PolyIran regarding aspirin in primary prevention contrast with the findings of the ARRIVE, ASCEND, and ASPREE trials, and what patient factors should influence the decision to use an aspirin-containing polypill?

Key Response

Recent trials (ARRIVE, ASPREE) suggested that in modern populations with well-controlled risk factors, the bleeding risk of aspirin often outweighs the ischemic benefit. However, PolyIran showed a benefit, likely because the cohort had higher baseline cardiovascular risk and lower background use of statins and antihypertensives. This suggests that aspirin-containing polypills are most effective in high-risk populations where primary prevention measures are otherwise underutilized.

Attending

Given the 34% reduction in MACE observed in PolyIran, should we reconsider the 'medicalization' of aging by recommending a polypill for all adults over a certain age and risk threshold, regardless of their current blood pressure or lipid levels?

Key Response

The PolyIran study supports a 'population-based' rather than 'individual-based' approach to cardiovascular health. For patients over 50, even those with 'normal' levels may benefit from the risk reduction. As a teaching point, this shifts the focus from treating 'numbers' to treating 'absolute risk,' though clinicians must balance this against polypharmacy and potential side effects in otherwise healthy individuals.

Scholarly Review

Critical appraisal through the lens of expert reviewers and guideline development

PhD

The PolyIran trial utilized a cluster-randomized design involving 236 villages. What are the statistical implications of using the village as the unit of randomization rather than the individual, particularly regarding the Intraclass Correlation Coefficient (ICC)?

Key Response

Cluster randomization is used to prevent 'contamination' (where control participants adopt intervention behaviors). However, it requires a larger sample size to maintain power because individuals within a cluster (village) tend to be more similar than individuals across clusters. The analysis must account for the ICC to avoid underestimating standard errors and inflating the significance of the findings.

Journal Editor

A critical reviewer might point out that the 'minimal care' control group did not receive a placebo. To what extent does the 'Hawthorne Effect' or the lack of blinding in this pragmatic trial threaten the internal validity of the reported Hazard Ratio?

Key Response

Because participants and providers knew who was receiving the polypill, the intervention group may have subconsciously improved other lifestyle factors (diet, exercise) or reported symptoms more frequently. Furthermore, 'minimal care' may not reflect the true standard of care in more developed healthcare systems, potentially overstating the relative effectiveness of the polypill in a global context.

Guideline Committee

Current ESC and AHA/ACC guidelines generally recommend individualized risk assessment (e.g., SCORE or ASCVD Risk Estimator) before initiating therapy. Based on PolyIran, is there sufficient evidence to recommend a Class I, Level A mandate for polypill use in primary prevention for all individuals with a 10-year risk >10%?

Key Response

While PolyIran provides strong Level A evidence for the polypill's efficacy, guidelines (like the 2021 ESC Guidelines on CVD prevention) still emphasize shared decision-making. The evidence supports a Class IIa recommendation ('should be considered') to improve adherence, but moving to Class I would require more data across diverse geographic and socio-economic settings to ensure that a fixed-dose approach is superior to individualized care across all health systems.

Clinical Landscape

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