Hypertension Canada’s 2020 hypertension guidelines for pharmacists: An update

Introduction

Canadian health professionals have had access to evidence-based Canadian hypertension guidelines on managing and diagnosing hypertension since 1999.¹ The 2020 guidelines produced by Hypertension Canada continue to be held to a high international standard and mark the 21st publication of the guidelines. The 2020 guidelines have outlined new recommendations and undertaken an exhaustive review of the existing ones and, where appropriate, removed recommendations that are out of date with the evidence or redundant.²

Hypertension management continues to be a Canadian health care priority. Community-based, pharmacist-led hypertension interventions yield significant clinical benefits; therefore, pharmacists are recognized as a vital component of the hypertension detection and management strategy in Canada.^3-11

The Canadian Pharmacists Journal has consistently published regular and relevant updates of the hypertension guidelines for pharmacists.^12-15 This article outlines updates with the release of the 2020 Hypertension Canada guidelines. We outline the new recommendations that are relevant for pharmacists and highlight existing recommendations that remain clinically important. Readers are encouraged to access the full guidelines in Canadian Journal of Cardiology² or on Hypertension Canada’s website (www.hypertension.ca).

What’s new

Terminology

Automated office blood pressure (AOBP) is still the preferred method of measurement for measuring blood pressure (BP) in the office. Where this method is not possible, office BP measurement (OBPM, previously known as non-AOBP) is suggested. Table 1 outlines the definitions and preferred methods of BP measurement according to the 2020 Hypertension Canada guidelines. Home BP monitoring (HBPM) is recommended for patients with inadequate BP control. HBPM values above ≥135/85 mmHg are considered high. We encourage pharmacists to refer to the full guidelines² on BP thresholds and targets for treatment initiation.

Table 1.

Hypertension Canada’s 2020 guidelines measurement definitions

Acronym	Definition
AOBP	Automated office blood pressure is performed using automated office oscillometric devices, the patient is seated in a quiet room (no specified rest period). The device is set to take measurements at 1-2 minutes intervals. The first measurement is taken with the provider in the room to verify cuff position and measurement. Then the patient is left alone in the room while to device takes subsequent measurements. Record the average BP as displayed on the device, the arm used, and the position of the patient.BP values considered high* = mean SBP ≥135 mmHg or DBP ≥85 mmHg (Grade D)	Preferred method of in-office measurement and diagnosis
OBPM	Office blood pressure measurement is performed using an upper arm device with the provider in the room. Oscillometric or electronic devices are preferred when using this method. The patient is rested in a seated position for 5 minutes before the reading. The provider performs 3 readings, discarding the first reading and the averaging the subsequent 2 readings. Auscultatory devices are an alternative if an electronic device is not available. BP values considered high† = SBP ≥140 mmHg or DBP ≥90 mmHg (Grade C)
ABPM	Ambulatory blood pressure monitoring requires the use of a validated oscillometric device, which must be worn by the patient for a 24-hour period, with measurements taken at 20- to 30-minute intervals during the day and night. BP values considered high* = mean awake SBP ≥135 mmHg or DBP ≥85 mmHg or mean 24-hour SBP ≥130 mmHg or DBP ≥80 mmHg (Grade C)	Preferred out-of-office methods for diagnosis
HBPM	Home blood pressure monitoring is a self-monitoring method, which requires the patient to measure their BP twice in the morning and evening for 7 days. BP values considered high* = SBP ≥135 mmHg or DBP ≥85 mmHg (Grade C)

Hypertension Canada 2020 guidelines measurement definitions adapted with permission from the Canadian Journal of Cardiology.²

BP, blood pressure; DBP, diastolic blood pressure; SBP, systolic blood pressure.

^*For people with diabetes, BP thresholds are yet to be established and may be lower.

^†For people with diabetes, BP value is considered high if the SBP ≥130 mmHg or DBP ≥80 mmHg.

Readers are encouraged to view the full guidelines for recommended BP measurement techniques.

Resistant hypertension

It is suggested that resistant hypertension (RHT) has an estimated prevalence of 10% to 30%.¹⁶ The Hypertension Canada 2020 guidelines for the management of RHT state a patient has apparent RHT if they are above target despite being on optimal doses of 3 or more antihypertensives, preferably including a diuretic.¹⁶ When diagnosing apparent RHT, it is important to rule out other causes—pseudo-resistance (nonadherence, white coat hypertension and treatment inertia) and secondary causes (Figure 1). Accurate BP measurements are required to diagnose true RHT, including AOBP or OBPM and ABPM or HBPM. The out-of-office measurement in addition to the in-office measurement allows for the exclusion of white coat hypertension.

Figure 1.

Diagnostic algorithm for a patient with suspected resistant hypertension

Reproduced with permission from the Canadian Journal of Cardiology.²

ABPM, ambulatory blood pressure monitoring; BP, blood pressure; HT, hypertension.

*Three or more drugs, at optimally tolerated dosages and preferably including a diuretic.

†Home BP monitoring can be performed if ABPM is not accessible.

Nonpharmacological management strategies (reduction of sodium, increase in potassium, weight reduction and reduction of alcohol intake) should still be integrated into the care of patients with RHT. Patients with RHT are typically on the base regimen known as A-C-D (angiotensin-converting enzyme [ACE] inhibitor/angiotensin receptor blocker with calcium channel blocker and diuretic) and a fourth antihypertensive agent. There is some debate as to what the fourth agent should be, as many RHT studies have reported only short-term outcomes.^17-19 The Hypertension Canada 2020 guidelines suggest the additional use of spironolactone, bisoprolol, doxazosin, amiloride or clonidine, in addition to the baseline regimen, to decrease BP in patients with RHT.¹⁶ The evidence suggests the largest BP reduction has been shown with spironolactone used as the fourth antihypertensive.^16,17,19 To assist in optimizing antihypertensive management, thiazide-like diuretics and medications with a longer duration should be used at the highest tolerated doses.¹⁶

Pregnancy

In women with hypertension, the possibility of pregnancy should be reviewed regularly while of childbearing age (Grade D). Uncontrolled hypertension within the first trimester of pregnancy can significantly increase maternal mortality and morbidity and threaten the viability of pregnancy.²⁰ Hypertension poses a significant risk for preeclampsia and other pregnancy-related complications.²¹

It is important that potential pregnancy is considered when deciding on antihypertensive treatment in women with hypertension. If a woman is considering pregnancy, it is suggested to stabilize hypertension with antihypertensive medications that are conducive to a viable pregnancy. According to the 2020 hypertension guidelines, renin angiotensin system (RAS) medications—ACE-inhibitors and angiotensin receptor blockers (ARBs)—should be discontinued prior to conception to reduce any possible risks of exposure to the fetus. Research has not established when these RAS medications should be discontinued, but their use during pregnancy has been associated with increased risk of fetal malformations.²² Treatment of hypertension in women who are pregnant should follow the Hypertension Canada guidelines for managing hypertension in pregnancy.^2,23 Furthermore, in women who are breastfeeding, antihypertensive medications that have been shown to have a low concentration in the breastmilk should be considered, including labetalol, methyldopa, long-acting nifedipine, enalapril or captopril.

Pharmacists are encouraged to provide preconception counselling to women with hypertension who are considering pregnancy. Pharmacists should also take pregnancy into consideration when prescribing or recommending antihypertensive therapy. The evidence is limited on the benefits of preconception counselling on risk reduction, but it provides an opportunity to increase health literacy and education for women with hypertension on the importance of hypertension management during pregnancy and the associated risks.^24,25

Aspirin recommendation removed for primary prevention of cardiovascular disease

The previous recommendation on the use of low-dose acetylsalicylic acid (ASA) for primary prevention of cardiovascular disease (CVD) has been removed in the 2020 hypertension guidelines. This recommendation for aspirin use was based on the 1998 Hypertension Optimal Treatment (HOT) randomized trial.²⁶ However, recent trials and meta-analyses have identified that the risk of major bleeds outweighs any marginal benefits of cardiovascular (CV) protection in primary prevention of CVD.^27-30

Alcohol use

Based on the available evidence, the 2020 Hypertension Canada guidelines have recommended healthy adults to abstain from alcohol or reduce their alcohol consumption to less than 2 standard drinks per day to prevent hypertension (Grade B). In patients with hypertension who drink more than 2 drinks per day, any reduction in alcohol consumption is recommended, as it is associated with a lowering of BP (Grade A).

Wood et al.³¹ identified a positive linear relationship between hypertension-related mortality and alcohol consumption (Hazard Ratio per 100 g per week higher consumption, 1.24; 95% confidence interval, 1.15-1.33). A systematic review of the effects of alcohol on BP found that in adults with hypertension who drink more than 2 drinks per day, lowering alcohol consumption resulted in lowered BP.³² This positive effect on hypertension from lowering alcohol consumption was determined to be dose dependent, with the largest hypertension-related effect observed in patients who drink 6 or more drinks per day.³²

Pharmacists are encouraged to educate their patients on the effects that alcohol consumption has on their BP and provide advice on lowering or abstaining from alcohol, considering that there is no safe limit for alcohol consumption.

Adherence

Nonadherence to medications for chronic conditions (like hypertension) is always a concern for pharmacists.³³ Nonadherence to hypertension treatment regimens is one of the major contributors to inadequately controlled hypertension and should be addressed. Many different factors can negatively influence patients’ adherence to antihypertensives.³⁴ There is no single methodology to assess patient nonadherence, but 2 reviews have identified nonadherence as a significant problem in patients with hypertension.^35,36

It is recommended that pharmacists routinely assess patients’ adherence to antihypertensive medications and discuss any possible factors that could be contributing to nonadherence. Assessing adherence to treatment regimens is imperative before considering changing or stepping up antihypertensive treatment or increasing antihypertensive doses. Patients are more satisfied and more likely to adhere to treatment plans that are collaboratively developed. We encourage pharmacists to engage in shared decision making with patients and other health care providers (e.g., family physicians) to develop a shared understanding of competing risks and benefits and come to an agreement on appropriate individualized targets and therapies. Motivational interviewing is suggested as a possible strategy in identifying nonadherence and providing a platform for recommending adherence strategies.³⁷ Another recommended strategy is to inform patients of their CV risk and the positive impacts changing their modifiable risk factors can have on their CV risk.⁵ We encourage pharmacists to refer to the full guidelines on possible strategies to improve patient adherence. Some of the suggested strategies are listed as follows²:

• Link medication schedule to a patient’s daily routine (Grade D)

• Condense medication schedule to once-daily dosing when possible (Grade D)

• Switch patient to single-pill combinations (Grade C)

• Use dose administration aids (Grade D)

• Incorporate a multidisciplinary team approach (Grade B)

• Encourage patient ownership of their disease management (Grade C)

• Provide education on hypertension and treatment options for the patient and their families (Grade C)

• Encourage adherence through out-of-office contact (either by phone or mail), particularly during the first 3 months of therapy (Grade D)

What is still important for pharmacists

Diagnosis

Hypertension Canada has updated the diagnostic algorithm for adults in the 2020 guidelines (Figure 2). This update clarified the information provided for patients with diabetes and BP measurements. Current evidence on measurement thresholds in patients with diabetes using AOBP, ABPM or HBPM is inconclusive. Thus, the current guidelines consider an OBPM of ≥130/80 mmHg on 3 or more measurements on different days sufficient to diagnose hypertension in a patient with diabetes, with the consideration of performing ABPM or HBPM to rule out white coat hypertension.

Figure 2.

Hypertension Canada’s 2020 guidelines diagnosis algorithm

Reproduced with permission from the Canadian Journal of Cardiology.² All measurement values in algorithm are reported as mmHg.

ABPM, ambulatory blood pressure measurement; AOBP, automated office blood pressure (performed with the patient unattended in a private room); HBPM, home blood pressure measurement; HTN, hypertension; OBPM, office blood pressure measurement (performed in the office using an electronic upper arm device with a provider in the room); WCH, white coat hypertension.

*If AOBP is used, use the mean calculated and displayed by the device. If OBPM is used, take at least 3 readings, discard the first and calculate the mean of the remaining measurements. A history and physical exam should be performed and diagnostic tests ordered.

†Serial office measurements over 3 to 5 visits can be used if ABPM or HBPM is not available.

‡Home BP series: Two readings taken each morning and evening for 7 days (28 total). Discard first day readings and average the last 6 days.

§In patient with suspected masked hypertension, ABPM or HBPM could be considered to rule this out.

Management

Pharmacists are strategically important in detecting and managing hypertension in Canada. There are over 4.5 million people in Canada who do not have access to a family physician.³⁸ It has also been acknowledged that patients visit their pharmacists up to 7 times more often than their other health care professionals (such as family physicians).³⁸ Pharmacists are in a unique position to proactively “case-find” individuals who may be unaware of their hypertension and who may not be being managed by a physician. There is high level of evidence supporting the benefits of pharmacists’ interventions on hypertension management, providing a cost-efficient service to patients.^5,6,39

Pharmacists can provide education and awareness of the risks of hypertension and modifiable risk factors to prevent or control hypertension. Educating a patient on their CV risk has been identified as a strategy to improving risk factor modifications (Grade B).¹⁵ Pharmacists should identify patients at high CV risk and provide intensive management as appropriate. The SPRINT trial identified patients as high risk for a CV event if they were aged 50 years or older with systolic blood pressure (SBP) levels ≥130 mmHg and had one of the following⁴⁰ (Grade B):

• Clinical or subclinical cardiovascular disease

• Chronic kidney disease

• Estimated 10-year global CV risk ≥15%

• Age ≥75 years

It is recommended to consider intensive hypertension management to below SBP <120 mmHg in these patients.⁴⁰

Follow-ups

There is strong evidence that patient gains from pharmacist-led interventions are diminished if there is no consistent follow-up.^41,42 Thus, the authors cannot stress enough the importance of follow-up visits for managing patients with hypertension. The schedule for follow-up depends on the individual patient and their symptoms/hypertension control. Patients on antihypertensive medications should be reviewed approximately every 1 to 3 months, depending on whether their hypertension is controlled or if dose adjustments and/or treatment regimen changes are required.² A patient’s CV risk should also be taken into consideration when determining duration of follow-up visits for an at-risk patient. Given that visits with the physician might not always be so frequent, the role of the pharmacists in follow-up is essential.

It is noteworthy that adequate BP control requires a multidisciplinary approach, involving physicians, pharmacists, nurses and other health care providers and, most important, patient engagement.

Conclusion

The 2020 Hypertension Canada guidelines present 6 changes that are relevant to pharmacists:

1. The terminology for office BP measurement conducted with the provider in the room has changed from non-AOBP to OBPM. This is important when reviewing the new guidelines, diagnosis and treatment algorithms.

2. Hypertension Canada has produced specific 2020 guidelines on the management of resistant hypertension, which include the use of a fourth antihypertensive agent.

3. Pregnancy should be considered at regular encounters when managing patients with hypertension of childbearing age. Preconception counselling should be offered to these women, and possible pregnancy should be accounted for when selecting antihypertensive treatments.

4. ASA is no longer recommended for primary prevention of CVD, and pharmacists should amend their actions accordingly.

5. There is no harmless amount of alcohol consumption in preventing hypertension, and abstinence or reduction of alcohol consumption should be recommended to patients at risk of or who have hypertension.

6. Potential nonadherence should be considered in patients before changing or stepping up their treatment for inadequate hypertension control.

Readers are encouraged to refer to the full guidelines² in the Canadian Journal of Cardiology or on the Hypertension Canada website (www.hypertension.ca), where additional patient and professional resources and tools can be found. Printable Hypertension Highlights pocket cards in both English and French can be found at https://guidelines.hypertension.ca/chep-resources. There are also additional educational materials available on the Hypertension Canada website for pharmacists, including a newly launched Hypertension Canada Professional Certification Program, which provides certification for pharmacists on hypertension management. To learn more about this new program, please visit Hypertension Canada’s website at https://hypertension.ca/professional-certification-program/.