In the 2011 guideline, high-dose thiazide diuretics were recommended as a potential step 4 treatment in people with high blood potassium levels. The committee felt that there was a lack of evidence for this approach and noted that the studies did not show an improvement in cardiovascular outcomes at higher doses, albeit in people without resistant hypertension. The committee agreed that the recommendation for considering alpha- or beta-blockers should be retained based on significant clinical experience of their safe and effective use and because adding a further drug is likely to have a greater effect on blood pressure than increasing the thiazide diuretic dose. How the recommendations might affect practice The recommendations represent current good practice and so should not change practice. High-dose thiazide diuretics are not commonly used as step 4 therapy and so removing this should not change practice. There might be a small reduction in step 4 treatment with more thorough checks to confirm resistant hypertension. However, this may also result in an increase in blood pressure measurements to appropriately confirm resistant hypertension where this is not already being done. Return to recommendations Identifying who to refer for same-day specialist review Why the committee made the recommendations There was no evidence identified to inform recommendations on this topic. The committee reviewed the 2011 recommendations and agreed that they should be updated by consensus based on their clinical expertise. In particular they agreed it would be helpful to clarify which features warranted same-day referral, which would need further investigation and when repeat blood pressure measurement should be taken. The committee noted that it can be difficult to differentiate between accelerated hypertension and severe hypertension. 