Hypertensive care in patients over 80 years old

The diagnosis of hypertension is slightly different for patients over 80 years old.

In the elderly over 80 years old NICE recommend a diagnosis of hypertension with a CBP ≥160/90mmHg and an ABPM of 155/85mmHg.

The recommended treat-to-target BP is also slightly higher, in aiming to achieve a CBP of <150/90mmHg or ABPM of <145/85mmHg2 in this age group.

The evidence for systolic targets has been changing recently with the SPRINT trial (Systolic Blood Pressure Intervention Trial) and this is discussed below.

Medication is the same as for those over 55 years of age.

Systolic BP rises with age and there is an increased risk of stroke with raised systolic BP. Treating to a systolic CBP of <150mmHg is supported by the joint guidelines from the European Society of Cardiology and European Society of Hypertension, which state that the benefits of anti-hypertensive treatment are limited to people with a BP consistently over 160mmHg systolic, and this should be reduced to below 150mmHg. Guidelines have not demonstrated any additional benefit in reducing CBP to <140mmHg in patients >80 years old.[1]

The Hypertension in the Very Elderly Trial (HYVET) is a comprehensive clinical trial exploring the benefits of anti hypertensives in patients over 80 years of age.[2] In this trial, there was a 30% relative risk reduction (RRR) in the rate of stroke in the treatment group (p=0.06) and a 21% RRR in death from any cause in the treatment group (p=0.02). This is equivalent to a number needed to treat (NNT) in preventing 1 stroke in 94 patients treated for 2 years.

In 2015, the American SPRINT study[3] supported the benefits of anti-hypertensive therapy. In their sub-group of patients aged >75 years, the primary outcome of reduced cardiovascular events was significantly lower in their intensive treatment group. The intensively treated group treated to a target systolic BP of 120mmHg whereas the non-intensive target group was treated to the usual systolic target of 140mmHg. The study for all ages was stopped early after 3.3 years. The NNT to prevent disease in the >75-year-old intensive treatment group was 27 to prevent one primary CVD event and 41 to prevent one all cause death over the 3.3 years[4] and was an improvement over the non-intensive therapy group. This study subgroup suggests that treatment to a lower systolic BP of 120mmHg was beneficial, but also pointed out that many patients were excluded from the trial protocol.

GPs have previously had concerns about an inverse relationship between BP readings and mortality rates in patients >80years old. The complications of anti-hypertensive medications, e.g. dizziness and syncope causing falls associated with low BP, is important.

Anti-hypertensives may also cause reduction in renal function, increased risk of acute kidney injury at times of intercurrent illness and electrolyte disturbances. Assessing the frail elderly is complex and chronological age does not always correlate with biological age. Treatment should take the full status of a patient, such as frailty into account. Essentially, not all patients over 80 are the same. GPs use their clinical judgement when prescribing treatment; weighing up the patient’s physiological performance, function and possible life expectancy as well as the patient’s own wishes.

Hypertensive women: preconception and pregnancy

Pre-conceptual counselling of women with known hypertension focuses on achieving good hypertensive control (and glycaemic control for diabetic women).[5] This is problematic as ACE-I and ARBs are first line anti-hypertensives in a non-pregnant population <55 years and are also recommended as a first-line agents in women with diabetes (DM) and systemic lupus (SLE) for control of hypertension and/or protein-losing nephropathy at any age. While use of these drugs would usually be considered good clinical care, in pregnancy these drugs are contra-indicated. In the second and third trimesters of pregnancy they increase the risks of oligohydroamnios, renal failure and intra-uterine death of the foetus. Their safety in the first trimester remains controversial. A study of nearly 30,000 infants with no evidence of maternal diabetes, showed a significantly increased risk of cardiovascular malformations (risk ratio: 3.72) and central nervous system malformations (risk ratio: 4.39) in infants exposed to an ACE-I in the first trimester.[6] In 2011, another study of 400,000 women-infant pairs showed an increased risk of congenital cardiac defects in infants subjected to ACE-I during the 1st trimester compared with healthy controls (odd ratio 1.54).[7] Exposure to an ACE-I at any point in pregnancy cannot currently be considered safe. This advice is supported by the American Society of Obstetrics and Gynaecology (ACOG) task force review which made a ‘strong’ recommendation cautioning against the use of ACE-I and ARBs in all trimesters of pregnancy.[8] A UK review between 1996 and 2010 found that 1.5% of women entered pregnancy on an anti-hypertensive. The discontinuation rate for ACE-I was 25% and for ARBs was 70%.[9] One of the common pitfalls will be young diabetic women trying to conceive while taking recommended non pregnancy ACE-I or ARB therapy, and GPs need to be aware of potential problems with medications.

The role of GPs in obstetric care has significantly declined over the years, and in 2007 the Department of Health published ‘Maternity Matters’, endorsing the direct self-referral of women to community midwifery services for the provision of antenatal care rather than firstly seeking a GP consultation.[10] This has caused deskilling of GPs in obstetrics, but GPs are the first point of contact for a majority of women, with approximately 78% booking their pregnancy with a GP in 2007.[11] It is therefore important that GPs are aware of current guidelines regarding the treatment of hypertension in pregnancy to prevent maternal and foetal adverse outcomes. Clinic BP readings are used in the assessment of the maternity patient by GPs. Hypertension in pregnancy is defined by NICE as a CBP ≥140/90mmHg and complicates 5-8% of all pregnancies.[12] The prevalence of hypertension in pregnancy is unfortunately rising. There is an increased incidence of mothers with a BMI classified as overweight (>25kg/m2) and obese (>30kg/m2). There is also a shift to later maternal age, with almost a trebling in the rate of pregnancies in women over 40 years old from 1987 (1.2%; 27,000 maternities) to 2008 (3.6%; 82,000 maternities). These two factors are major predisposing causes for hypertension in pregnancy.[13] In addition, more women with significant co-morbidities, such as chronic kidney disease (CKD), SLE and diabetes, are embarking on pregnancy.

Hypertension in pregnancy can be sub-classified into 3 categories:

  • Chronic hypertension
  • Gestational hypertension
  • Pre-eclampsia.

ACE-I, ARBs and a thiazide diuretic called chlorthiazide are contra-indicated in pregnancy as their harms may exceed their benefits, and these medications should be stopped.[14] The severity of hypertension is categorised[14] for all 3 types of pregnancy hypertension as:

  • mild (140/90-149/99 mmHg)
  • moderate (150/100-159/109mmHg)
  • severe (160/110mmHg or higher)

The NICE pregnancy guideline sets out monitoring dependent on hypertensive severity. For GPs, though it is enough to recognise the risks of hypertension in pregnancy, check the CBP and urinalysis and refer to the obstetric team any women with CBP measurements above 140/90.

Chronic hypertension

This is hypertension known about prior to pregnancy, or recognised before 20 weeks of gestation. Most young women have their first BP reading when attending the GP practice for contraceptive care, but some will have their first reading at their early pregnancy booking, so would be a new diagnoses. The diagnosis is made by a CBP ≥140/90mmHg on at least 2 occasions, a minimum of 4 hours apart unless severe and requiring immediate referral.[8] The aim of treatment is to maintain BP <150/100mmHg.[14]

Gestational hypertension

This is defined as hypertension occurring after 20 weeks gestation, without the presence of proteinuria. Proteinuria is the excretion of more than 0.3g of plasma protein into the urine within a period of 24 hours. In general practice it is commonly diagnosed by +1 protein on a urine reagent test strip. Awaiting a urinary albumin:creatinine ratio (ACR) delays proteinuria results by at least 24 hours, and so may delay the diagnosis of pre-eclampsia and is not advised. GPs should make an immediate referral to obstetric secondary care. The aim of treatment is to keep the BP <150mmHg systolic and the diastolic between 80- 100mmHg.[14]

Pre-eclampsia

This is a rare but serious complication of hypertension in pregnancy. The same three hypertensive categories of mild, moderate and severe BP are as above, but it is also defined by hypertension occurring after 20 weeks gestation with significant proteinuria (>0.3g/24hours). Women with a diagnosis of chronic or gestational hypertension have a 17-25% risk of developing pre-eclampsia compared with just 3-5% of pregnant women in the population without these conditions.[15] Pre-eclampsia is associated with serious maternal morbidity and is a leading cause of direct maternal deaths in the UK.[16] Women may develop clinical symptoms, commonly severe headaches (usually frontal); sudden oedema of face, feet or hands; visual disturbances (blurring of vision, flashing lights), epigastric abdominal pain and/or vomiting. In these cases, immediate hospital admission and management is needed. Women at risk of pre-eclampsia are offered aspirin 75mg a day from 12 weeks gestation with evidence of a small reduction in rates of pre‑eclampsia.[17]

Pregnant women with pre-existing chronic hypertension or a previous history of gestational hypertension, DM, CKD and autoimmune diseases such as SLE or anti-phospholipid syndrome are at high risk of developing pre-eclampsia, and from 12 weeks gestation to delivery these women should be prescribed aspirin 75mg once a day by an obstetrician,[14] unless there are contraindications.

Moderate risk factors for pre-eclampsia are: maternal age >40 years old; BMI >35; nulliparous; pregnancy interval >10 years; multiple pregnancy and a family history of pre-eclampsia in a first degree relative. Women with >1 of these moderate risk factors are also prescribed aspirin 75mg once a day unless there are contraindications.

A Cochrane Review supported the view that aspirin is of more benefit to women with a major risk factor versus a moderate risk factor. The absolute risk reduction (ARR) in pre-eclampsia for women with a major risk factor was -5.2% versus -0.84% for women with a moderate risk factor.[18]

GPs are rarely a party to the care of hypertensive pregnant women so for those attending their GP the patient-held record is invaluable. Postnatally hypertension should be monitored and the risks of developing future gestational hypertension or pre-eclampsia discussed with patients.

There is controversy regarding the benefits of anti-hypertensive medications in pregnant women with mild or moderate chronic hypertension, with some studies suggesting that the benefits of anti-hypertensives are minimal. A meta-analysis[19] concluded that the effects of anti-hypertensives for those women with mild or moderate hypertension halved the risk of women developing one or more episodes of severe hypertension. The evidence that treatment prevents progression to pre-eclampsia is less convincing.[20]

The majority of international guidelines including NICE[14] and the Society of Obstetrics Medicine of Australia and New Zealand (SOMANZ)[21] recommend anti-hypertensive treatment to women with hypertension to maintain a BP <150/100mmHg. NICE suggests maintaining a diastolic BP of 80- 100mmHg. The CHIPS trial[22] investigated pregnant women with non-severe hypertension and found no difference in perinatal or maternal outcomes in women with non-proteinuria and chronic or gestational hypertension, whether treated to a diastolic<100mmHg or to a diastolic <85mmHg. There was no significant difference in the rate of severe maternal pregnancy complications (28.9% versus 30.6%) or the need for high level neonatal care for more than 48 hours (2.2% versus 2.7%). The progression to severe hypertension in pregnancy was higher in the less-tightly controlled group (40.6% versus 27.5%). NICE recommend that diastolic BP should not be treated to a level <80mmHg.[14]

First line treatment for maternal hypertension if required is with beta blockers (mostly labetalol) and calcium channel blockers (mostly nifedipine) as first line agents.[13,14] These drugs have had wide use in pregnancy over many years and so are preferred to newer agents, for which the safety data is not as robust. Labetolol is contraindicated in asthmatics due to bronchospasm, and nifedipine is an alternative. Methyldopa continues to be recommended in severe hypertension by a variety of clinical practice guidelines outside the UK.[23] No trial to date has reported neonatal malformations or serious adverse maternal outcomes with any of these drugs; they are the safest in pregnancy and effective in managing hypertension. A meta-analysis of 21 trials reported hydralazine is associated with more maternal hypotension, oliguria and higher rates of placental abruption and caesarean section, in addition to more adverse effects on foetal heart rate than labetalol or nifedipine, which has resulted in its use being generally outdated.[24]

Conclusion

In summary, hypertension can be a complex diagnosis in particular population sub-groups, including pregnant women and the very elderly. It is a serious risk factor for maternal and foetal morbidity in pregnancy and cardiovascular mortality in the elderly. In the community, GPs should use their expertise to lower future risks of hypertension. GPs are skilled at weighing clinical benefits and harms of therapy and anti-hypertensives with each individual patient and require awareness of the recommendations according to the patient’s life stage. Also, there are pitfalls in practice in not recognising the pregnant patient, so it is therefore important to diagnose any hypertensive disorder in pregnant women and in woman wanting to conceive while taking ACE-Is or ARBs.

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Mennatella Gharib MRes intercalation student, year 4/5 University of Liverpool.

Dr Jane Wilcock Year assessment lead and clinical community tutor, University of Liverpool School if Medicine, part-time GP Silverdale Medical Practice, Pendlebury health Care.