RCGP SCA Algorithm — UK Primary Care
Most high cholesterol is incidental — but do not miss these critical associated presentations.
Familial hypercholesterolaemia affects 1 in 250 people in the UK (260,000 individuals) but only 7% are diagnosed. Untreated FH carries a 50% risk of CHD by age 50 in men, 30% in women. The key is cascade screening — every FH patient identified has 50% chance of first-degree relative being affected. Hypertriglyceridaemia >10 mmol/L requires urgent management as acute pancreatitis risk is substantial. Secondary causes (hypothyroid, nephrotic, DM, alcohol) must be treated before statin initiation or the lipid picture will not resolve.
Risk stratification using QRISK3 determines whether to treat, not cholesterol level alone.
QRISK3 replaced Framingham in UK guidelines because it includes additional risk factors (SMI, SLE, AF, deprivation, migraine) with better calibration in UK populations. NICE NG238 (2023) uses 10% threshold for statin offer — this is a change from previous 10% primary prevention threshold. The key insight is that a patient with TC 8 mmol/L but QRISK3 of 5% needs lifestyle advice, not a statin, while a patient with TC 5 mmol/L but QRISK3 25% needs atorvastatin today.
Always exclude secondary causes before labelling someone as primary hypercholesterolaemia — hypothyroidism is present in ~5% of new dyslipidaemia referrals and treating thyroid normalises lipids without statin. FH identification matters enormously: a 35-year-old with untreated FH has the same risk as a 55-year-old without it. Cascade screening should be offered to all first-degree relatives of FH patients — 50% will be affected.
Tendon xanthomata are pathognomonic of FH — finding them in a patient with TC >7.5 gives definite FH by Simon Broome criteria without genetic testing. Achilles tendons are the most common site — run finger along the tendon and feel for nodules or thickening. Corneal arcus is significant in patients under 45 but is a normal finding in elderly patients. A thorough BP measurement at this consultation is as important as the lipid result — undertreated hypertension quadruples CV risk even on statins.
NICE NG238 (2023) moved to LDL-C targets rather than just TC:HDL ratio — align with ESC guidelines. LDL <2.0 mmol/L in secondary prevention is backed by multiple RCTs showing progressive risk reduction with lower LDL (Mendelian randomisation studies support "lower is better"). Statins cause ALT elevation in ~1–3% of patients — baseline LFTs allow interpretation of subsequent results. Routine pre-statin CK is not recommended by NICE — it causes unnecessary statin avoidance due to asymptomatically elevated CK from exercise.
PCSK9 inhibitors (evolocumab, alirocumab) reduce LDL by a further 50–60% on top of maximum statin — they are indicated when LDL remains >2.6 mmol/L despite maximum tolerated statin in secondary prevention or FH. They are only available via specialist initiation on NHS due to cost (~£4,500/year vs £20/year for statin). FH cascade screening through NHS CHOL programme is free and identifies high-risk relatives before they develop CVD — every GP FH identification potentially saves multiple lives through family screening.
NICE CKS / NG238 treat the two groups differently — the starting dose and the treatment target both change depending on whether there is established CVD.
Escalation when target not met — step up only after rechecking non-HDL at 2–3 months. GP / primary care Refer to secondary care
Muscle symptoms: Check CK if symptomatic. CK >4× ULN: stop statin. CK <4×: continue and review. Most "statin myalgia" is nocebo effect — trial of different statin or rechallenge important.
Each mmol/L reduction in LDL-C reduces major CV events by ~22% (Cholesterol Treatment Trialists). Atorvastatin is first-line over simvastatin because of fewer drug interactions and better potency per mg. High-intensity statin in secondary prevention reduces CV events by 25–35% over 5 years (NNT ~15–20). Ezetimibe added to statin gives additional 6–7% CV event reduction (IMPROVE-IT trial). The nocebo effect accounts for 70–80% of reported statin intolerance — rechallenge with a different statin leads to successful treatment in most patients.
The PREDIMED trial showed Mediterranean diet reduced major CV events by 30% over 5 years — comparable to statin therapy — without the medication burden. Combined lifestyle changes can reduce LDL by 1.0–1.5 mmol/L without medication, which is equivalent to low-dose statin. The key message for patients is that lifestyle is not an optional add-on to statins — it is a concurrent treatment that amplifies statin benefit and may be sufficient alone in low-to-moderate risk patients.
The 3-month lipid recheck is the critical intervention point — studies show that patients not at target after 3 months need proactive intensification, not watchful waiting. Without intensification at 3 months, ~60% of high-risk patients remain above LDL target. Statin-associated muscle symptoms affect 5–10% of patients in trials but much higher in clinical practice — systematic re-examination (rechallenge, different statin, alternate dosing) recovers tolerable treatment in 80% of cases. Statins in pregnancy carry a risk of structural abnormalities — women of childbearing age must be counselled and contraception discussed.