I am pleased that this new yearly volume of the Journal of Hypertension opens with a new set of hypertension guidelines . The International Society of Hypertension (ISH) had published their last guidelines jointly with the WHO back in 2003 , and therefore ISH recommendations on management of hypertension were expected with deep interest. Likewise, it is now more than 10 years since the 7th Joint National Committee Report  was published and the expectations of having the authoritative opinions of American experts on the matter are unfulfilled yet. Thus, the common document of the ISH and the American Society of Hypertension (ASH) now meet both expectations.
Only few months ago, the Journal of Hypertension has published the new edition (2013) of the European Society of Hypertension (ESH) and the European Society of Cardiology (ESC) guidelines in an extensive version  and in a more concise one , and nowadays specialists and practicing physicians in charge of individuals with hypertension have a wide spectrum of opinions about how to manage their patients.
When multiple guidelines are produced, the easiest temptation is to contrast them in order to provide ground for learned debates among experts. Undoubtedly, the most obvious difference between the ASH/ISH and the ESH/ESC guidelines is in their length: 13 pages for the former and 76 pages for the latter. This points to an unresolved issue about the format of guidelines. Should any recommendation be supported by a detailed discussion of the weight and type of evidence upon which it is based, and practicing physicians instructed about the strength of each recommendation, and informed about which statement is supported by trial evidence and which by the experts’ wisdom only? This approach requires an extensive document, and even when a shortened version is prepared for practitioners’ usage the extensive document should be consulted for learning the supporting background of every recommendations. Or, vice versa, should guideline documents be short and agile, easy to read and, in particular, to follow in medical practice, mixing trial evidence with experts’ wisdom, without exposing practicing physicians to the dilemma whether their decisions are evidence based or wisdom based only?
The problem has been recurrent through the history of hypertension guidelines, as it results from two opposite, difficult to reconciliate requirements: to provide straightforward, simple recommendations and, on the same time, to inform the physicians not only about what they should do, but also about why they should follow any specific recommendations for the management of hypertension. Probably, the only realistic solution is the availability of different guidelines, each using a different format, so that every doctor can choose the approach he/she finds more appropriate for his/her needs. This is what we have now with two sets of guidelines, those recently provided by ESH and ESC, and the present one by ASH and ISH.
When different guidelines are published at about the same time, rather than searching for differences, it is certainly more productive to underline similarities, as similarities between guidelines are the strongest support for their acceptance and widespread use. Undoubtedly, on all most important issues of hypertension management, the ESH/ESC and the ASH/ISH guidelines provide quite similar recommendations, and are mutually supportive. The definition of hypertension, as a SBP at least 140 mmHg or a DBP at least 90 mmHg is identical; the diagnostic approach is substantially similar with attention called on the possible presence of additional risk factors, diabetes and cardiovascular disease; the value of measuring 24-h ambulatory blood pressure or blood pressure at home is duly underlined without making out-of-office blood pressure measurement a requirement before deciding initiation of treatment; laboratory tests recommended to be included in the initial diagnostic approach are also substantially the same in the two sets of guidelines.
As to the clinically crucial matter of initiation of antihypertensive drug treatment and the blood pressure goals to be achieved, ASH/ISH guidelines appear to agree with the innovations first introduced by the 2009 ESH Reappraisal document  on the basis of a critical review of trial data , and translated into the 2013 ESH-ESC guidelines [4,5]. Initiation of treatment is recommended in all individuals with blood pressure values at least 140/90 mmHg, independent of confirmation by 24-h ambulatory blood pressure monitoring or of high cardiovascular risk, but only after a prolonged (6–12 months) period of life style changes, an approach that is considered ‘prudent’ by European guidelines as well, although they admit that evidence from trials is scant. As to blood pressure goals of treatment, such as European guidelines [3,4] the new ASH/ISH guidelines recommend goals of less than 140/90 mmHg for all hypertensive patients independent of the level of cardiovascular risk, except in elderly people aged 80 years or more for whom a goal of less than 150 mmHg is recommended (ESH/ESC guidelines [4,5] have similar recommendations for the elderly but use a lower threshold for defining old age). Similar is the acknowledgement in both sets of guidelines that no clinical trial evidence is available in patients younger than 50 years, and that in these individuals DBP may be more important than SBP.
As far as treatment is concerned, criteria for initiation with monotherapy or combination therapy are the same in the two sets of guidelines, the same classes of drugs are considered, and both guidelines agree that choice of drugs is mainly based on concomitant risk factors or diseases, the only divergence being the weight given to age in the ASH/ISH guidelines (age also enters in an algorithm suggested by these guidelines), whereas ESH/ESC guidelines do not consider age as a relevant criterion for drug choice.
In conclusion, although the two sets of guidelines appear to have a somewhat different overall approach (with the ESH/ESC guidelines aiming at more rigidly separating evidence based from opinion-based recommendations, whereas the ASH/ISH document prefers to offer a single type of recommendations, independent of their being based on either evidence or wisdom), the substantial convergence of definitions, diagnostic procedures and therapeutic interventions recommended by these two major guidelines should be seen as a valuable opportunity for widening consensus and strengthening all necessary efforts toward improving adherence to antihypertensive treatment and making primary and secondary prevention of cardiovascular disease ever more successful.
Conflicts of interest
There are no conflicts of interest.
1. Weber MA, Schiffrin EL, White WB, Mann S, Lindholm LH, Kenerson JG, et al. Clinical Practice Guidelines for the Management of Hypertension in the Community. A Statement by the American Society of Hypertension and the International Society of Hypertension. J Hypertens
2. World Health Organization, International Society of Hypertension Writing GroupWorld Health Organization (WHO)/International Society of Hypertension (ISH) statement on management of hypertension. J Hypertens
3. Chobanian AV, Bakris GL, Black HR, Cushman WC, Green LA, Izzo Jl Jr, et al. Seventh report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure. Hypertension
4. Mancia G, Fagard R, Narkiewicz K, Redon J, Zanchetti A, Böhm M, et al. The Task Force for the management of arterial hypertension of the European Society of Hypertension (ESH) and of the European Society of Cardiology (ESC)2013 ESH/ESC guidelines for the management of arterial hypertension. J Hypertens
5. Mancia G, Fagard R, Narkiewicz K, Redon J, Zanchetti A, Böhm M, et al. ESH/ESC Task Force for the Management of Arterial Hypertension2013 Practice guidelines for the management of arterial hypertension of the European Society of Hypertension (ESH) and the European Society of Cardiology (ESC). J Hypertens
6. Mancia G, Laurent S, Agabiti-Rosei E, Ambrosioni E, Burnier M, Caulfield MJ, et al. Re-appraisal of the European guidelines on hypertension management: a European Society of Hypertension Task Force document. J Hypertens
7. Zanchetti A, Grassi G, Mancia G. When should antihypertensive drug treatment be initiated and to what levels should systolic blood pressure be lowered? A critical re-appraisal. J Hypertens