Cost-effectiveness of statin therapy in categories of patients in the UK

Background

Cardiovascular disease (CVD) mortality has declined steadily over the last few decades across Europe and North America.

Purpose

To provide contemporary estimates of long-term effectiveness and cost-effectiveness of statin therapy in different categories of patients in UK.

Methods

The CTT-UKB micro-simulation model, developed using the Cholesterol Treatment Trialists' Collaboration data (CTT: 118,000 participants; 5 years follow-up), and calibrated in the UK Biobank cohort (UKB: 502,000 participants; 9 years follow-up). The model integrates parametric risk equations for incident myocardial infarction, stroke, coronary revascularization, diabetes, cancer and vascular and nonvascular death, and projects annually these endpoints and survival using patient characteristics at entry. UKB data and linked primary and hospital care data informed healthcare costs in the model (2020 UK£); 2021 UK NHS Drug Tariff informed statin costs (atorvastatin 40mg at £1.22 and 80mg at £1.68 per 28 tablets); and Health Survey for England data informed health-related quality of life in the model. Previous CTT meta-analysis, atorvastatin dose-response randomized trials, and further meta-analyses of statin trials and cohort studies informed effects of 40mg/80mg atorvastatin therapy daily on rates of incident myocardial infarction, stroke, coronary revascularization, vascular death, diabetes, myopathy and rhabdomyolysis.

The model was used to project gains in quality-adjusted life years (QALYs) and additional cost per QALY with lifetime use of atorvastatin 40mg or 80mg daily in categories of UKB participants by sex, age at statin initiation (40–49; 50–59 and 60–70 years), and 10-year CVD risk (QRISK3 risk (%): <5; 5–10, 10–15, 15–20, ≥20). Further scenarios explored effects of 5-year delay of statin initiation in people under 45 years of age or stopping statin therapy at 80 years of age.

Results

Across men and women in categories by age and CVD risk, lifetime use of atorvastatin 40mg daily was associated with increases in survival by 0.44–1.69 years (0.28–1.02 QALYs), and atorvastatin 80mg daily with increases in survival of 0.45–1.87 years (0.32–1.13 QALYs; Figure 1) with gains larger among participants at higher CVD risk. Both atorvastatin 40mg and 80mg doses were in the range of cost-effective treatments with incremental cost per QALY gained with atorvastatin 40mg daily versus no statin therapy below £7200/QALY and with atorvastatin 80mg vs 40mg daily below £16000/QALY (Figure 2) across all patient categories studied. Compared to lifetime statin therapy, stopping therapy at 80 years of age substantially reduced benefits and was not cost-effective in any patient category studied. Similarly, compared to immediate initiation, 5-year delay of statin therapy in 40–45 years old patients was not a cost-effective.

Conclusions

In the UK, statin therapy remains highly cost-effective across men and women 40–70 years old, including those at 10-year CVD risk <5%.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): UK National Institute for Health Research (NIHR) Health Technology Assessment (HTA) Programme, UK National Institute for Health Research (NIHR) Health Technology Assessment (HTA) Programme, UK Medical Research Council (MRC), British Heart Foundation

Antiplatelet therapy use for the secondary prevention of cardiovascular disease in 2009–2017: a population-wide retrospective cohort study of Scotland

Background

Few studies have analysed the adequacy of antiplatelet therapy (APT) use for secondary prevention of atherosclerotic cardiovascular disease (ASCVD). Some studies found utilisation to be suboptimal. However, information on the extent of APT use at different treatment stages and over time, and the role of particular individual characteristics, is limited.

Purpose

To use large-scale population-wide individual patient data to investigate the extent of, and determinants for, suboptimal use of effective APT, in order to identify patient groups that could be targeted to improve medication use.

Methods

This retrospective open cohort study used anonymised large-scale population-wide individual patient NHS Scotland data (hospital admissions, national death records, prescribing information and speciality mental health admissions) for all individuals hospitalised for ASCVD (based on ICD-10 discharge codes) in Scotland between 1 October 2009 and 31 December 2017. APT initiation was defined as a prescription of APT within 90 days of ASCVD hospital discharge with dispensing within 60 days of the prescription. Adherence was defined as ≥80% of days covered with dispensed therapy. Discontinuation of APT was defined as a treatment gap of 180 days or more since initiation. Multivariable cross-sectional logistic regression and Cox proportional hazards models were used to study the relevance of patient characteristics (e.g., demographic, clinical, socioeconomic) to the likelihood of, respectively, initiating or discontinuing APT. Findings are reported for all ASCVD events and, separately, for myocardial infarction (MI), ischaemic stroke, peripheral arterial disease (PAD) and other ASCVD events.

Results

Of 150,728 individuals hospitalised for ASCVD (excluding any diagnosis of atrial fibrillation), 16% did not initiate any APT. Initiation was less common in women (22% less likely than men), people aged ≥70 or <50 (21% and 39% less likely for patients in their 70s and 80s respectively vs. 60s; 26% less likely for patients below age 50 vs. 60s), people living in more deprived areas, people receiving specialist mental health care and people with multiple morbidities (Figure). There was substantial variation for lack of initiation across ASCVD types (e.g., MI 6%, PAD: 32%). In 2015/17, 72% of MI patients and 69% of patients undergoing percutaneous coronary intervention received guideline-recommended dual-APT. While on treatment, 93% of users were adherent. However, about a quarter (23%) discontinued treatment. Similar characteristics linked to lack of initiation of APT were associated with an increased risk of discontinuation.

Conclusions

APT initiation and persistence remain suboptimal, especially in women, people aged below 50 years and 70 years or older, people with multiple morbidities or mental illness, and following non-MI ASCVD events. This needs to be addressed by clinicians and policy-makers to further reduce cardiovascular risk.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Oxford British Heart Foundation Centre of Research Excellence (BHF CRE) Pump Priming Scheme; Medical Research Council Doctoral Training Programme (MRC DTP) studentship.

Benefit accrual with cardiovascular disease prevention and effects of discontinuation: a modelling study

Background

Statin therapy reduces rates of heart attacks and strokes and improves survival in people at increased cardiovascular disease (CVD) risk. However, there is some uncertainty when to start and how long to persist with statin therapy so as to optimise benefits.

Purpose

To project the accrual of benefit with statin therapy in population groups by age at therapy initiation using a newly developed micro-simulation model.

Methods

Participants without previous CVD (N=44,412) and with previous CVD (N=13,061) at entry were randomly selected from the UK Biobank cohort, ensuring sufficient representation in respective categories by age, LDL cholesterol, diabetes and 10-year CVD risk categories (QRISK3 score, for those without previous CVD only). The CTT-UKB model, a CVD micro-simulation model [1], was used to predict subsequent survival and quality-adjusted life years (QALYs) of the participants using their characteristics at entry. Treatment with atorvastatin 40mg daily was used as an example to illustrate the effect of the therapy compared to no such therapy. Scenarios include: (1) lifelong preventive therapy, (2) preventive therapy stopped at 80 years of age, and (3) delayed initiation of preventive therapy by 5 years in participants under 45 years of age.

Results

Statin treatment benefits, measured in QALYs gained, accrue over lifetime. The majority of benefits accrue later in life. Men accumulate larger benefits and earlier than women (Figure 1A). The pattern of benefits accrual is similar for participants with and without previous CVD (data not shown). The higher the participants' CVD risk, the larger and earlier the benefits, with younger participants accruing larger benefits (Figure 1B). Compared with lifelong prevention, stopping treatment at 80 years of age leads to large reductions in overall benefits, especially in women and those at lower CVD risk. For example, compared to lifelong therapy, people without previous CVD who initiate therapy in their 50s, would lose 47% of QALYs benefit (if men), 66% (if women), 73% (if with CVD risk <5%), and 35% (if with CVD risk ≥20%), respectively, if they stop treatment when they reach 80 years of age. Five-year delay of statin therapy initiation in people under 45 years of age reduces their benefits by about 4% on average, though the loss is somewhat larger in people at higher CVD risk (Figure 2).

Conclusion

Benefits from lifelong cardiovascular prevention accrue over peoples' lifespan with large share of benefits accruing at older age. Stopping treatment earlier substantially reduces benefits.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): UK NationalInstitute for Health Research (NIHR) Health Technology Assessment (HTA) Programme, UK Medical Research Council (MRC), and British Heart Foundation

A model of lifetime health outcomes in cardiovascular disease based on clinical trials and large cohorts

Background and purpose

Cardiovascular disease (CVD) risk of individuals depends on their socio-demographic characteristics, clinical risk factors, and treatments, and strongly influences their quality of life and survival. Individual-based long-term disease models, which aim to more accurately calculate the lifetime consequences, can help to target treatments, develop disease management programmes, and assess the value of new therapies. We present a new micro-simulation CVD model.

Methods

This micro-simulation model was developed using individual participant data from the Cholesterol Treatment Trialists' collaboration (CTT: 118,000 participants; 15 trials) and calibrated (with added socioeconomic deprivation, ethnicity, physical activity, mental illness, cancer and incident diabetes) in the UK Biobank cohort (UKB: 502,000 participants). Parametric survival models estimated risks of key endpoints (myocardial infarction (MI), stroke, coronary revascularisation (CRV), diabetes, cancer and vascular (VD) and nonvascular death (NVD) using participants' age, sex, ethnicity, physical activity, socioeconomic deprivation, smoking history, lipids, blood pressure, creatinine, previous cardiovascular diseases, diabetes, mental illness and cancer at entry and non-fatal incidents of the key endpoints during follow-up. The model integrates the risk equations and enables annual projection of endpoints and survival over individuals' lifetimes. The model was used to project remaining life expectancy across UK Biobank participants.

Results

Nonfatal cardiovascular events and age were the major determinants of CVD risk and, together with incident diabetes and cancer, of individuals' survival. The cumulative incidence of the key endpoints predicted by the CTT-UKB model corresponded well to their observed incidence in the UK Biobank cohort, overall (Figure 1) and in categories of participants by age, sex, prior CVD and CVD risk. Predicted remaining life expectancy across UK Biobank participants without history of CVD ranged between 22 and 43 years in men and between 24 and 46 years in women, depending on their age and CVD risk (Figure 2). Among UK Biobank participants with history of CVD, depending on their age, predicted remaining life expectancy ranged from 20 to 32 years in men and from 26 to 38 years in women.

Conclusion

This new lifetime CVD model accurately predicts morbidity and mortality in a large UK population cohort. It will be made available to provide individualised projections of expected lifetime health outcomes and benefits of treatments.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): UK National Institute for Health Research (NIHR) Health Technology Assessment (HTA) Programme, UK Medical Research Council (MRC), British Heart Foundation Figure 1. Predicted (in black) versus observed (95% CI; in red) incidence of major clinical outcomes in the UK Biobank.Figure 2. Predicted remaining life expectancy of participants in UK Biobank cohort, by age and CVD risk or previous CVD at entry. QRISK, a 10-year CVD risk scoring algorithm for people without previous CVD, recommended for use in the UK National Health Service.

Determinants of statin initiation and discontinuation in the secondary prevention of atherosclerotic cardiovascular disease in Scotland during 2009–2017

Background

Previous studies have shown that use of statins for secondary prevention of cardiovascular disease (CVD) is suboptimal. However, the role of particular individual characteristics at different treatment stages is limited.

Purpose

To use large-scale population-wide individual patient data to investigate reasons for suboptimal use of effective CVD medications, in order to identify patient groups that could be targeted to improve medication adherence.

Methods

This observational longitudinal study used anonymised linked NHS Scotland administrative data (General/Acute Inpatient and Day Case, the National Records of Scotland and the Prescribing Information System) for all individuals hospitalised for an atherosclerotic CVD event (based on ICD-10 discharge codes) in Scotland between 1 April 2009 and 31 December 2017. Statin initiation was defined as individuals being prescribed statin therapy within 90 days from index discharge and dispensed within 60 days from that prescription. Discontinuation was defined as the start of first statin treatment gap of 180 days or more since initiation. Multivariate logistic regression and Cox proportional hazards models were used to study the relevance of patient characteristics (e.g. demographic, clinical, socio-economic) and admission calendar year to the likelihood of, respectively, initiating or discontinuing statin treatment. Findings are reported for all CVD events and, separately, for myocardial infarction (MI), ischaemic stroke (IS) and peripheral arterial disease (PAD).

Results

Of the 178,113 patients hospitalised for CVD, 19% did not initiate statin treatment. Among the 144,077 patients initiating (40% on high-intensity statins, as defined by NICE guidelines), 25% discontinued treatment within 2 years. Initiation was less common in women (29% less likely than men), older people (22% and 50% less likely for patients in their 70s and 80s respectively vs. 60s), people living in more deprived areas, people receiving specialist mental health care, people with multiple morbidities and people not taking statin prior to admission (Figure). Most of these characteristics were also associated with a decreased likelihood of initiating high-intensity statins, as well as an increased risk of discontinuing statin therapy. In later years, levels of statin initiation, including on higher-intensity statins (58% of statin initiators in 2015–17 vs. 32% in 2009–11), and statin persistence have improved.

Conclusions

Rates of statin initiation and discontinuation remain suboptimal, especially among women, older people and people with multiple morbidities or mental health illness.

Figure 1. Patient characteristics associated with initiation and discontinuation of statin treatment after atherosclerotic CVD event.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): British Heart Foundation Centre of Research Excellence (Pump Priming Scheme), Medical Research Council UK