Lifetime risk and 10 year risk
This is the chance of developing cardiovascular disease by the age of 99 - and, if a lower age is entered, up to that age - from the lifetime model rather than the 10 year one. It allows for the competing risk of dying from another cause first, which rises steeply with age, so the figure does not simply keep climbing in older patients. "What if?" is the same patient with good control of smoking, body mass index, cholesterol/HDL ratio and blood pressure.
The two measures answer different questions. A younger person with several risk factors can have a low 10 year risk and a high lifetime risk, because that risk has decades to accumulate. Treatment thresholds in NICE guidance are set on 10 year risk, so the lifetime figure is best read alongside the QRISK3 10 year score rather than instead of it.
QRISK4 and QRISK3
QRISK4, published as QR4, is the successor to QRISK3 from the same research team. It keeps the risk factors QRISK3 uses and adds nine more that were found to raise the risk of cardiovascular disease: chronic obstructive pulmonary disease, learning disability, Down's syndrome and cancers of the brain, lung, mouth and blood in both sexes, and pre-eclampsia and postnatal depression in women. It was also derived from more recent records, so it reflects current patterns of disease and treatment.
In its validation study QRISK4 predicted risk more accurately than QRISK3, and for the same patient the two scores will usually be close. They differ most where one of the additional conditions applies. QRISK4 can be used from age 18; QRISK3 starts at 25. The QRISK4 paper is listed on the publications page.