Problems with hypertension guidelines

Congratulations to Schofield et al¹ on their thought-provoking paper looking at hypertension and ethnicity. Three points occur. How useful are NICE guidelines, and in terms of an ethnic population, how accurate are they? Also in an era of austerity could they be harmful to patient care? Adherence to NICE recommendations was relatively low in the inner-city population studied. No evidence was found of significantly poorer control in patients on any of the ‘incorrect’ treatments. In 2006² and 2011² the National Institute for Health and Clinical Excellence (NICE) has stratification of antihypertensives. Other contemporaneous guidelines disagree. The 2007 and 2009³ European Society of Hypertension (ESH) and European Society of Cardiology (ESC) concluded all diuretics, ACE inhibitors, calcium antagonists, angiotensin ii receptor blockers (ARB), and beta-blockers were suitable for the initiation of and maintenance of antihypertensive treatment. ESH argued the traditional ranking of drugs into first, second, third, and subsequent choice with an average patient as reference has little scientific justification.

The American Joint National Committee 7 (JNC) (2003) soon to be superseded by JNC 8 concluded that thiazide diuretics were unsurpassed in preventing the cardiovascular complications of hypertension. Australian 2010 guidelines contradicted NICE arguing that in uncomplicated hypertension ACE inhibitors, dihydroperidone calcium channel blockers were equally effective as a first-line treatment. The World Health Organization (WHO) in 2007 published a document offering a further variation. Given that non-adherence made no difference to blood pressure control and the differing opinions of other authorities, how useful are the current NICE guidelines?

The area of ethnicity is interesting in blood pressure guidelines. Schofield points out that lower renin levels in young black people reduce the response to ACE inhibitors. This is well known. Studies have traditionally neglected both ethnic minorities, and that 50% of the population who happen to be female. The ALLHAT⁴ study was correctly praised for having ratios of 47% female, 35% black American, and 19% Hispanic. ALLHAT provided part of the justification for NICE’s recommendation for thiazide diuretics if calcium channel blockers were ineffective for black people of African–Caribbean descent of any age. But ALLHAT looked at patients of 55 years or older, the mean age was 67 years. It provided no evidence for those under 55 years. It didn’t look at black British people. Johnson observed that many black British people may belong to what is now viewed as an emergent ‘mixed’ origin population of the UK that can be genetically significantly different from black Americans. The evidence for NICE guidelines in ethnic minorities I would argue is weak and may answer Schofield’s question as to why GPs and patients in this study opted for alternative treatment regimes.

Majeed’s⁵ editorial noted that general practices in England could face reductions of 20% in their annual budgets. Is it only a matter of time before prescribing is limited? Could this be based on guidelines with a weak evidence base?