Prevention, they say, is better than cure. Public health strategies have focussed on the provision of safe drinking water, safe sewage disposal and mass vaccination. These have greatly reduced death and illness from infectious diseases.
Preventative strategies are now being taken further; your GP will ask ‘screening’ questions, and you might get an invitation for a mammogram or for a bowel cancer check. We’ve all heard about the need to eat five portions of veggies a day (unless you are Greek, when it’s nine portions), exercise, lay off the cigs and be moderate with the booze (killjoys!). (And lots of sex—or at least ejaculation—throughout life distinctly reduces the risk of prostate cancer, but, strangely, this isn’t often mentioned.) But now, should we treat the population for what might be called the natural progression of ageing? As we age, our chances of having raised blood pressure and raised cholesterol do seem to increase and thereby influence our risk of cardiovascular disease, the number one cause of death and morbidity.
While there are vigorous proponents advocating the treatment of asymptomatic problems, people who are almost evangelists in their arguments, people saying that all over, say, 50, should be on a cocktail of drugs—almost whether they need them or not—other voices are much more cautious.
The New Scientist published an article about this recently, asking whether mass preventative pill taking was justified. The New Scientist has recognised that medicine, like economics, is often a very political subject. I’m going to concentrate here on cardiovascular disease, specifically high blood pressure and high cholesterol.
High blood pressure (hypertension)
Blood pressure (BP) gradually rises as we age, how much this is ‘functional’ and how much is pathological is uncertain. A high BP is associated with heart attacks and strokes, and with kidney failure.
So, what should a patient’s blood pressure ideally be? Well, a modest rise doesn’t seem to be that harmful, but a big rise is. And treatment of this has aimed at a reduction to a ’safe’ level. However, the ‘goalposts’ keep moving, and what yesterday was an acceptable if raised BP is today seen as too high.
There are several classes or types of pill for raised BP. Some, diuretics, aim to make you pee out ‘excess’ fluids and salts; others act more directly on the blood vessels, particularly the arterioles, involved in the regulation of BP.
High cholesterol (hypercholesterolaemia)
The cholesterol in our bodies comes from fatty food that we eat, but also from our own manufacture. So, even completely omitting cholesterol from our diet won’t eliminate it in the blood; indeed, some level of cholesterol is necessary for proper cellular function. Cholesterol can be deposited in our arteries as ‘plaques’; it there is a clot (a thrombus) on these, the artery can be blocked, leading to a heart attack or an apoplectic stroke.
Statins are a group of drugs which lower blood cholesterol, and also give a better balance between the ‘good’ and ‘bad’ varieties. It’s clear, that if you have had a heart attack, and have raised cholesterol, that treatment with a statin reduces your risk of a further attack. It might seem sensible to say that even if you haven’t had a heart attack, and have no symptoms, but do have raised cholesterol, then treatment will reduce your future risk of a heart attack. This is the nub of the argument for prescribing statins to ‘healthy’ people. However, the results of trials aren’t so clear cut; often, recommendations seem to come down to a matter of ‘belief’ in the efficacy or otherwise of statins. The decision to start statins may depend on your age; perhaps if you are young, but with a very high cholesterol you should have treatment; but if you are an otherwise asymptomatic nonagenarian, is it really sensible?
Like blood pressure, the ‘goalposts’ for ideal cholesterol levels in the blood do get altered from time to time; and always downwards.
Aspirin was originally the German company Bayer’s trade name for acetylsalicylic acid. It’s been known from antiquity as a remedy for headache. Originally prepared from the bark of the willow (Salix species, hence the chemical name) an identical molecule is now made synthetically. The Bayer company didn’t think much of it initially, preferring to direct their efforts at another vegetable extract, heroin. Aspirin is anti-inflammatory, and interferes with blood coagulation by an action on platelets. It has been associated with significant stomach (gastric) bleeds; a much lower dose is used as to prevent a blood clot forming on a plaque.
There are algorithms which can calculate your risk of a heart attack given your age, weight, BP etc. It used to be that a risk greater than 20% was an indication for treatment; now, the level is 10% (and lower in the US). However, determining whether it is sensible to take treatment can be very difficult. Often, the effects of drugs are given as ‘risk reduction’. Now, a claim that a drug reduces your chance of death by 50% sounds impressive; this is relative risk reduction. But if we look closer, we might find that if your risk is, say 2%, and that treatment reduces it to 1% you might well wonder if it’s worth it; this is absolute risk reduction. And you might find this all expressed rather differently; treatment might have to be given to, say, 10,000 people to save one or two lives; this is the number needed to treat. It’s no surprise that which statistic you use can be determined by your viewpoint; a drug company may use relative risk; an epidemiologist, the number needed to treat.
Side effects are things that drugs do that we don’t want them to. If you read the information leaflet with your pills, you’ll see a long list of these side effects. Any medical student knows that all drugs can cause gastrointestinal upsets and rashes; some side effects are more specific. And any cynic will tell you that if a drug doesn’t have side effects, then it doesn’t have any effects at all.
During clinical trials of drugs, patients are closely monitored for unexpected effects. When drugs come to market, doctors are advised to report any ‘adverse’ effects; how many do isn’t certain. So, the frequency of side effects is a bit uncertain, and is anecdotally higher than described. Calcium channel blockers, used in BP treatment, are known to cause leg swelling or ‘oedema’. I asked a senior colleague about this, and he reckoned that perhaps 25% of his female patients had this problem, and not liking thick ankles, stopped the drug; this is a far higher proportion than official statistics suggest. A very commonly prescribed treatment, statins, seem to have a much higher incidence of depression and insomnia than reported, to the extent that many patients stop them after a few years. (During a trial of the BP treatment sildenafil, it was found not to be very effective; but male patients frequently reported a strange though welcome side effect. And, after ‘rebranding’, voila! a single factory in Cork struggled to meet world demand for Viagra.)
Grapefruit is a natural hybrid between an orange an a pomelo. It interacts with at least 85 drugs; some interactions are serious, potentially fatal. The patient advice leaflets on statins and calcium channel blockers have warnings about grapefruit juice.
What should I do?
Well, a facile answer begins with where you are now. More exercise, less fags, less booze, more greens is a good start. But beyond that: well, that’s not so easy for any individual. In part it depends on your ‘risk factors’ and how much you can reduce them, if you are willing; it depends on your approach to ‘authority’—do you do as your are told, or are you argumentative, questioning the reasoning behind the decisions? Are you willing or unwilling to accept a certain level of ‘risk’ in a population, not knowing whether the risk will apply to you? Trying to work out the individual benefits versus risks versus side effects for any pill isn’t so simple, and much more complicated when it’s suggested you might need several, typically something to lower your BP, a statin and aspirin—for starters.
Note: the above is background information not medical advice, for which you should attend your general practitioner or an appropriate specialist.
Robert Campbell is a retired surgeon.