Management of mild hypertension in adults
BMJ 2016; 355 doi: https://doi.org/10.1136/bmj.i5719 (Published 21 November 2016) Cite this as: BMJ 2016;355:i5719All rapid responses
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Dr.s Hart, Spitzer and Barraclough make critical points and I hope the authors reply soon. What is so annoying though is that the BMJ publishes these articles without the editorial team spotting that the basics we need to help people decide if they want to become patients not being there. Years ago the mrc mild hypertension trial failed to show benefits in all groups or with all agents, and it would be useful to have a basic nnt for each drug class if any.
Competing interests: No competing interests
Viera and Hawes make an important, though non-controversial point, in saying that lifestyle interventions are the first line of treatment in mild hypertension. Not everyone agrees on which lifestyle interventions. There are at least two (and probably more) subsets of “essential” hypertension.
The first phenotype, associated with persistent hyperglycaemia in men with waists >37” and women with waists > 34”, increases blood viscosity and blood pressure. Reducing the duration and extent of the hyperglycaemia by (i) reducing carbohydrate intake, (ii) whole-body exercise e.g., swimming, reduces blood pressure to levels that, often, do not require pharmacological treatment.
The second phenotype results from narrowing of renal arterioles associated with persistent straining during defaecation that occurs in the uterus, and, is also supplied from sympathetic segments T10-12 (1-3). This refractory form of hypertension may require catheter-based, endovascular ablation of injured renal nerves for its treatment (4). Clearly, advice regarding diet and bowel habits may also be helpful?
Home-based, sphygmomanometry and glucose meters optimize daily feedback for individual patients who can titrate their own diets and metabolism against their blood pressure. Medicine has been very slow to engage in self-management of hypertension with cheap, widely-available and reliable, clinical measurement devices.
(1) Wu XQ, Cai YY, Xia WT, Yang SM, Quinn MJ. The aetiology of preeclampsia, 1945-1953. BJOG 2016 (in press).
(2) Quinn MJ. The aetiology of narrowed uterine arterioles in obstetric and gynaecological syndromes. Placenta 2016: 44:414-5.
(3) Wu XQ, Cai YY, Xia WT, Quinn M. All-Cause and Cause-Specific Mortality After Hypertensive Disease of Pregnancy. Obstet Gynecol. 2016 Dec; 128(6):1445-1446.
(4) Schlaich MP, Sobotka PA, Krum H, Lambert E, Esler MD. Renal sympathetic-nerve ablation for uncontrolled hypertension. N Engl J Med. 2009, 27;361(9):932-4.
Competing interests: No competing interests
According to Table 1, it seems that most of my non-hypertensive patients now have prehypertension (120-139/80-89)... I am so happy for the few people who don't have it - I think they only have pre-pre-hypertension. (But they all still get the same lifestyle advice, whether prehypertensive or pre-pre-hypertensive...)
Competing interests: No competing interests
For a gp in a busy clinical practice I am on the look-out for important clinical innovation and want to keep up to date. The issue of whether or not to treat uncomplicated mild hypertension is an important question. This review highlights the results from a recent meta-analysis (1) quoted as showing significant reductions in total cardiovascular events, heart failure and cardiovascular deaths and total deaths; the results for strokes, coronary deaths were not significantly reduced. The authors also quote another meta-analyses of selective trials to show that reductions in blood pressure in the mild hypertension range produced reductions in relative risk for stroke and coronary heart disease [2]. So, we have heterogeneous reductions in odds ratios and relative risk for various cardiovascular outcomes for people treated with uncomplicated mild hypertension.
The authors move from this sketchy evidence to advocating drug treatment. This advice is not supported by the evidence they have chosen to discuss. We are not informed of absolute risk reductions achieved and are therefore unable to calculate numbers needed to treat or other clinically meaningful numbers.
The conclusion of the article should have been that reducing blood pressure has been shown in some trials to reduce cardiovascular events. Without clear effect sizes it is impossible to know how clinically important these are. Clinicians should continue to follow NICE guidance that suggests that the benefits of treating uncomplicated mild hypertension, taking into account treatment costs and clinically meaningful patient benefit, remain unproven. If you wish to propose a change to extend treatment to lower risks then show us the money: what are the absolute risk reductions, how many people need to take tablets to avoid an event and how much will all of this cost.
Dr Ben Hart
GP
References
1. Sundström J, Arima H, Jackson R, et al. Blood Pressure Lowering Treatment Trialists’ Collaboration. Effects of blood pressure reduction in mild hypertension: a systematic review and meta-analysis. Ann Intern Med2015;162:184-91. doi:10.7326/M14-0773 pmid:25531552.
2. James PA, Oparil S, Carter BL, et al. 2014 evidence-based guideline for the management of high blood pressure in adults: report from the panel members appointed to the Eighth Joint National Committee (JNC 8). JAMA2014;311:507-20. doi:10.1001/jama.2013.284427 pmid:24352797.
Competing interests: No competing interests
The authors have done a great deal of work and the review is useful in gathering the information together. However, I had thought that we, as a profession, had accepted that (particularly within the field of primary prevention) absolute measures, such as absolute risk reduction (ARR) or numbers needed to treat (NNT) are absolutely crucial to informed consent for patients (and are extremely helpful for doctors). The main basis of the paper is the meta-analysis in Table 2 in the paper version, or Table 4 in the web version. Neither give a single assessment of absolute benefit - other that a single footnote in Table 4 that points out that the increased odds ratio of death in the treated group in one study of 3.98 (which is slightly worrying) was on the basis of only two deaths (that’s a relief). This is the only absolute measure in the whole, huge meta-analysis. It is also presumably of some importance that this particular 2015 meta-analysis, which showed some statistically significant relative risk reductions and is the basis of most of the recommendations, was made up almost exclusively of patients with diabetes. This (crucial) fact is mentioned once in the table but nowhere in the text. The conclusion drawn by the authors is that: “pooling the results from these trials showed that anti-hypertensive treatment with in patients with mild hypertension likely prevents cardiovascular events, particularly stroke and mortality.” Is this really correct when the 2012 meta-analysis showed no benefit and the 2015 meta-analysis was almost all made up of diabetic patients? The authors discuss the SPRINT study but this has absolutely no relevance to whether low risk patients with mild hypertension should be treated because 90% of the patients enrolled in SPRINT were already on anti-hypertensive drugs, 20% already had cardiovascular disease and 60% had significant risk factors.
If I try and explain this data to a patient on Monday morning would I be correct in saying that there is absolutely no evidence that treating a patient with mild hypertension and no other risk factors with drugs gives any benefit? I am getting to the age where I may need to take anti hypertensive drugs myself. It would be nice to know what my chances are of benefiting (my absolute attributable risk reduction) from taking treatment for, say, 5 years. It would also be useful to know if my risk of acute kidney injury is 4.1% per year (SPRINT intensive treated group) and what my risk of conking out and breaking my hip is.
I have felt uncertain and uncomfortable about treating low risk people with hypertension ever since the last NICE guidance came out. I am sure I am not alone in this. Reverting to meta-analyses like this, that give little indication of absolute levels of risk and risk reduction, does seem to be a bit of a regressive step.
Competing interests: No competing interests
Dear Editors,
Alternate or unilateral nostril breathing is easy to learn and has numerous health benefits, including reducing high blood pressure.
Motivated GPs could help patients by teaching this ancient relaxation technique.
References
http://www.ncbi.nlm.nih.gov/pubmed/8132418
http://www.ncbi.nlm.nih.gov/pubmed/12152408
http://www.ncbi.nlm.nih.gov/pubmed/2282294
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3978938/
http://www.ncbi.nlm.nih.gov/pubmed/24116880
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3681046/
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3679963/
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3628802/
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3410188/
http://www.ncbi.nlm.nih.gov/pubmed/22315816
http://www.ncbi.nlm.nih.gov/pubmed/16579403
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4247229/
http://www.youtube.com/watch?v=MCK1jBfRVsE
Competing interests: No competing interests
There is no doubt about hypertension and its relation to subsequent life threatening diseases like stroke and myocardial infarction. Lifestyle changes are recommended as first line intervention. With medical interventions available and the initial stage of hypertension having minimal or few manifestations, lifestyle modifications aren't practised to the desired level by the majority of people, hence to leading early enrolment of anti-hypertensive medications. Also with the progression of time, atherosclerosis becomes more pronounced, pressing for the addition of further anti-hypertensive medications and making blood pressure control a difficult domain.
Competing interests: No competing interests
Re: Management of mild hypertension in adults
We thank Drs. Hart and Barraclough for their thoughtful comments. We agree that our article reviews available literature for treating mild hypertension, which is limited and suboptimal. As discussed in the article, the benefits of blood pressure reduction in people with mild hypertension, especially those with low cardiovascular risk are not clear. Absolute risk reductions are indeed important to take into account when considering BP-lowering treatment. As the article points out, we suggest that absolute cardiovascular risk be assessed when considering the management of patients with mild hypertension (which is indeed a new paradigm that models modern approaches to lipid-lowering treatment and aspirin use for primary prevention). The relative risk reductions can then be used to estimate the absolute risk reductions. For patients with low CVD risk, the absolute risk reductions from treating mild hypertension will be small. On the other hand, for patients with high CVD risk, the absolute risk reductions will be of greater magnitude. These estimates can be used in shared-decision making discussions (weighing potential harms and potential benefits) with patients who have mild hypertension.
Our article compares and contrasts the two available meta-analyses. Of note, the 2015 analyses evaluated a larger sample size of subjects and included studies assessing more optimal pharmacotherapy. We did, in fact, mention in both table and text that most of the patients included in this analysis had diabetes. As we noted, the SPRINT trial was included to offer insight into blood pressure treatment goals despite not being a trial treating mild hypertension. In conclusion, given the low quality of evidence for treatment of mild hypertension, it is necessary to consider the cost of treatment, the pill burden, and the potential benefit and side effects when making a shared decision with patients.
Competing interests: No competing interests