The annual Canadian Hypertension Congress was held from Oct 22-24, 2015 in Toronto. One of the highlights of this conference is the presentation of the Canadian Hypertension Education Program (CHEP) guidelines. These recommendations are regularly updated, and have been updated annually since 1999, which is a contrast with other hypertension guidelines (eg, JNC). The process of the guidelines begins with review of evidence which starts in April and is compiled by many subgroups (eg, on blood pressure measurement, renal and renovascular hypertension, pharmacotherapy with coexisting heart disease to name a few). If there is a change necessary based on the evidence, this is reviewed again by a Central Review Committee. The process culminates with a consensus conference of the entire recommendation task force (RTF, comprising over 60 family doctors, internists, pharmacologists, cardiologists, nephrologists, endocrinologists, neurologists, nurses) where each change is discussed, debated and finally drafted. These guidelines, along with slide sets are freely available on the website, and are quite well received and used in the hypertension community. There is also an app available now (iOS and Android versions). What follows are the new *draft* recommendations, which still are not yet ratified, but once done will be published in the Canadian Journal of Cardiology sometime in early 2016. This post will cover the changes compared to the 2015 guidelines, and some of the discussion about the need for change, which were revealed by Dr Doreen Rabi, chair of the review committee on Saturday, Oct 24.
Automated office blood pressure (AOBP) is now the preferred method for performing in-office blood pressure measurement. This refer to the automated oscillometric devices that measure BP every few minutes and provide an average, and a lot of this research has been done by Dr Myers from Toronto (see link for some of his papers). There is evidence from this and other studies that the measurements with these devices provide more accurate numbers compared to casual blood pressure measurement in the office. It can also perhaps eliminate some component of white coat effect, correlates with ambulatory blood pressure measurement, and now some data supports AOBP in prognostication. There is an added cost for a physician practice to purchase these devices (typically around $750-1000 each) and the practice setting has to be such that there is more than one room – or a semi-private waiting area that this could done in. Notable is the widespread use of the AOBP in research already – eg, in the much-awaited SPRINT trial. It should be stressed, however, that this refers to in-office and does not substitute for out-of-office blood pressure monitoring. Out-of-office monitoring, usually by ambulatory blood pressure monitoring, but increasingly using home monitoring devices, is the required next step in confirming the diagnosis of hypertension. (As an aside, our group has reported that AOBP may perhaps exacerbate masked hypertension and give an inflated proportion of hypertension control.)
Routine Lab Tests
As part of routine evaluation after diagnosis of hypertension, CHEP recommends chemistry (sodium, potassium, creatinine), fasting blood glucose or HbA1c, urinalysis, 12-lead ECG, and fasting lipids. A change was made today to allow for non-fasting lipids, unless the patient had known hypertriglyceridemia. There is data suggesting consistency between fasting and non-fasting, especially for HDL and total cholesterol. More importantly, there is also data supporting prognostic use of non-fasting lipids with outcomes. Moreover, non-fasting tests seriously lower the burden of getting tests done for patients, and improve the adherence of getting tests done. Lastly, this harmonizes with the other Canadian guidelines (especially the Canadian Cardiovascular Society), which we value highly in Canada.
This was a new section this year, and covered a lot of ground. Many of these guidelines were grade C or D, given the paucity of literature in this area. Some of the striking recommendations were
- BP measurement to be done regularly after 3 years of age (which seems rigorous, but apparently preferred given a significant proportion of secondary hypertension)
- The thresholds for diagnosis are based on normative data (PDF available at this NIH link), so hypertensive if >95th percentile for age, sex, and height
- Accurate BP measurement is key, needless to say, and there are differences in aneroid, auscultatory and oscillometric devices, thus auscultatory devices recommended when the values are flagged as abnormal
- Even in children, hypertensive children need global cardiovascular risk assessment – they have a higher prevalence of hyperlipidemia and diabetes
- Renal parenchymal disease and renovascular disease accounts for the vast majority of secondary hypertension
- Workup in all hypertensive patients should include echocardiography, renal ultrasound, blood chemistry and urine for albuminuria
Health Behaviours for Management of Hypertension
This includes sodium restriction (current recommendation to keep it less < 2000 mg/day), exercise, and stress reduction. The previous recommendation suggested that there was role for calcium, magnesium and potassium replacement. While calcium and magnesium replacement was not changed, there is a new recommendation, to increase dietary potassium intake to reduce blood pressure. This relies mainly on a WHO-commissioned systematic review which reported a robust effect of increased potassium intake on blood pressure reduction, and also on stroke. As a clinician, one would have to be careful to make sure the patient is not at risk for hyperkalemia (given that renin-angiotensin-aldosterone inhibitors are widely used for hypertension). This new recommendation also harmonizes with the WHO guidelines, and also with the fact that the DASH diet is already recommended by the CHEP, which provides about 120 mmol (4700 mg) of potassium.
Click here for a collection of tweets on CHEP.
– Post written by Dr. Swapnil Hiremath, AJKD Blog Contributor.
NB: Disclosure: SH is a member of the task force for the Canadian Hypertension Education Programme. The opinions expressed here are that of the author, and do not represent the CHEP guidelines or process.