This is a must read guideline! The main changes are: using Ambulatory Blood pressure monitoring (ABPM) to diagnose hypertension, using different cut off levels for treatment in the over 80s, using calcium channel blockers (CCB) as first line in the over 55s and good-bye to bendrofluazide.
They split hypertension into 3 ‘stages’. HBPM is home blood pressure monitoring:
- Stage 1 Clinic ≥ 140/90 and ABPM or HBPM ≥ 135/85
- Stage 2 Clinic ≥ 160/100 and ABPM or HBPM ≥ 150/95
- Severe Clinic ≥ 180/110
HBPM should be done on 7 consecutive days, discarding readings from day 1. It should be done sitting, with 2 readings a minute a part, twice a day.
If a clinic blood pressure reading is ≥ 140/90, offer ABPM 1st line, then HBPM 2nd line. This is because ABPM predicts outcome much better than clinic readings (eg MI / stroke). HBPM is not as good as ABPM, but probably better than clinic readings.
Carry out further assessment whilst awaiting diagnosis. Do: ACR, dipstix for haematuria, UE, cholesterol, check fundi and an ECG. Use the clinic readings to risk score the patient.
Who to initiate treatment in?
- Stage 1 if under 80 years old and one or more of:
- Target organ damage
- Established CV disease
- Renal disease
- 10 yr risk 20% or greater
- NB – if under 40 consider specialist referral to look for secondary causes
- Stage 2 – Offer to any age
- Severe – Consider starting medication immediately.
Targets (normally based on clinic readings)
- Under 80: Clinic BP < 140/90 (ABPM / HBPM < 135/85).
- Over 80: Clinic BP < 150/90 (ABPM / HBPM < 145/85).
- White Coat Effect – if there is ≥ 20/10 difference between ABPM / HBPM and clinic readings at diagnosis, consider using ABPM / HBPM as an adjunct to clinic readings.
- Postural hypotension – monitor with the patient standing.
Choice of Treatment:
Forget ABCD – it is now AC
- Step 1 – under 55s ACEi over 55s / Afro-Caribbean CCB
- Step 2 – ACEi + CCB
- Step 3 – ACEi + CCB + thiazide like diuretic
- Step 4 – ACEi + CCB + thiazide like diuretic at higher dose OR spironolactone OR a-blocker OR b-blocker.
Rationale behind this change and other notes:
- B-blockers are less effective than other drugs.
- CCB are cheapest option in over 55s (if using the cheapest CCB)
- Thiazide like diuretics start people on these, eg chlortalidone (12.5mg to 25mg OD) or indapamide (1.5mg MR or 2.5mg OD). These have good evidence of effectiveness and impact on outcome, which lower dose thiazides don’t. If people are already on bendrofluazide and are controlled, you can leave them on.
- B-blocker + thiazide like drugs avoid if can due to risk of diabetes
- Thiazides at higher doses / spironolactone. Don’t start spironolactone if K+ is over 4.5, use a thiazide at higher dose instead. Always check UE within 1/12.
Evidence behind suggested lifestyle changes - Just out of interest…
- Most lifestyle changes have only a small average effect on blood pressure, eg in the region of 5mmHg at most. Adding different changes together may not make much difference. However in a reasonable number of people, lifestyle changes can make a really good difference, so it is those people we are aiming the advice at.