Porter Health

QRISK3 Calculator

UK NHS Primary Care Cardiovascular Risk Assessment Tool

What is QRISK3?

QRISK3 is a cardiovascular disease risk prediction algorithm developed in the United Kingdom in 2017. It estimates the 10-year risk of developing cardiovascular disease (heart attack or stroke) in individuals aged 25-84 without pre-existing CVD.

QRISK3 was developed using data from 7.89 million patients in the UK QResearch primary care database and is the official risk calculator recommended by the UK National Institute for Health and Care Excellence (NICE) for CVD risk assessment in the NHS.

Key Innovation: QRISK3 was the first major risk calculator to incorporate a wider range of medical conditions (including rheumatoid arthritis, lupus, severe mental illness, and migraine) and medications (atypical antipsychotics, steroids) as independent risk factors.

What QRISK3 Calculates

QRISK3 provides a single 10-year risk estimate for total cardiovascular disease, which includes:

Coronary heart disease (myocardial infarction, angina)

Ischemic stroke

Transient ischemic attack (TIA)

Peripheral arterial disease

Note: Because QRISK3 includes TIA and PAD in addition to heart attack and stroke, it may produce higher risk estimates compared to calculators that only predict CHD and stroke (like PREVENT's CHD risk). This is expected and reflects the broader definition of cardiovascular disease.

Variables Used in QRISK3

Standard Risk Factors:

Age (25-84 years)

Sex (Male/Female)

Ethnicity (9 UK ethnic categories)

Smoking Status (5 categories: non, former, light, moderate, heavy)

Systolic Blood Pressure

Systolic BP Standard Deviation (variability)

Total Cholesterol / HDL Ratio

Body Mass Index (BMI)

Diabetes (Type 1 or Type 2)

Family History of CVD (age <60)

Chronic Kidney Disease (stages 3-5)

Blood Pressure Treatment

Additional Medical Conditions (Unique to QRISK3):

Atrial Fibrillation

Rheumatoid Arthritis

Systemic Lupus Erythematosus (SLE)

Severe Mental Illness

Migraine

Erectile Dysfunction (males)

Use of Atypical Antipsychotic Medications

Use of Regular Steroid Tablets

UK-Specific Factor:

Townsend Deprivation Score (measure of socioeconomic status)

Interpreting Your QRISK3 Score

UK NICE guidelines use the following QRISK3 thresholds for clinical decision-making:

Low Risk

<10%

Focus on lifestyle advice and modification of individual risk factors

Moderate Risk

10-20%

Consider lifestyle modification plus statin therapy; discuss benefits and risks with patient

High Risk

≥20%

Recommend statin therapy plus comprehensive lifestyle intervention

UK NICE Guideline: Statin therapy should be offered to individuals with a QRISK3 score ≥10% after discussing benefits, risks, and patient preferences.

QRISK3 vs PREVENT: Key Differences

QRISK3 and PREVENT are both evidence-based cardiovascular risk calculators, but they were developed for different populations and measure slightly different outcomes:

Feature	QRISK3 (2017)	PREVENT (2024)
Geography	UK-based	US-based
Population	UK Biobank (7.89M patients)	Multi-ethnic US cohorts (3M+ participants)
Primary Outcome	Total CVD (combined CHD + stroke + TIA + PAD)	Total CVD (separate predictions for CHD, stroke, HF, ASCVD)
Timeframes	10-year only	10-year AND 30-year
Age Range	25-84 years	30-79 years
Kidney Function	CKD stages (qualitative)	eGFR (required) + UACR (enhanced model)
Unique Risk Factors	Rheumatoid arthritis, SLE, migraine, mental health meds, erectile dysfunction	HbA1c, UACR, Social Deprivation Index

Clinical Comparison from Porter Health Data: In our analysis of Porter Health alpha testers with complete data, we compared 10-year CVD risk predictions:

Average PREVENT 10-year CVD risk: 1.4%

Average QRISK3 10-year CVD risk: 2.8%

Average difference: -1.5% (QRISK3 approximately 42% higher than PREVENT)

Risk category agreement: 100% (all alpha testers classified as "Low" risk by both calculators)

Note: The higher QRISK3 estimates are expected because it includes additional cardiovascular outcomes (TIA, PAD) beyond heart attack and stroke, and was calibrated to the UK population which may have different baseline risk compared to the U.S. population.

How QRISK3 is Used in Porter Health

Porter Health includes QRISK3 as a complementary risk calculator to provide a second perspective on cardiovascular risk:

Data Collection: We map your health data to QRISK3 input variables (with defaults for UK-specific factors like Townsend score and BP variability)

Comparative Analysis: We display both PREVENT and QRISK3 scores to help you understand your risk from different perspectives

Clinical Context: We explain why the two calculators may differ and what that means for your care

Primary Guidance: PREVENT is used as the primary calculator for U.S. patients, with QRISK3 providing additional context

Scientific Evidence

Primary Source

Hippisley-Cox J, Coupland C, Brindle P. Development and validation of QRISK3 risk prediction algorithms to estimate future risk of cardiovascular disease: prospective cohort study. BMJ. 2017;357:j2099.

DOI: 10.1136/bmj.j2099

Official Calculator: https://qrisk.org/three/

License: The QRISK3 algorithm implementation used in Porter Health is based on the open-source code released by ClinRisk Ltd. under the GNU Lesser General Public License (LGPL). The original source code is available at http://svn.clinrisk.co.uk/opensource/qrisk2.