GUIDELINES GALORE, NO GUIDANCE!
Posted by bmhegde on 1
Dear Sir,
“Typical patients are far from typical”
Voltaire.
One more guideline! There are already six or more guidelines. When computed together they cover less than half of the hypertensive population in their inclusion criteria. The remaining half does not fit into any guideline. The practising doctor will have to use his/her "intelligent guess" under those circumstances since there are no typical patients.
While we recommend combined therapy, based on arm chair reasoning, there are hardly any controlled studies of drug combinations that resemble the long laundry list prescriptions of real world these days.(1)
Even under ideal conditions, combinations of drugs had more side effects that forced patients to withdraw from studies. Despite that intention-to-treat analysis was used to compute the final results.(2) I am not aware of any study that looked at the very long term effects of anti- hypertensive drugs given to apparently healthy population in the fond hope of averting strokes, heart attacks etc. One small study did show that, after the first five to ten years of drug treatment, even the well controlled hypertensives had much higher death rates compared to their normotensive cousins in society. (3)
We still have no data to show how low is low enough blood pressure, as the J-curve still haunts us in this area. The J-curve was not burnt out even by the modern studies.(4) We do not know what happens to the sleep blood pressures in those patients having very low clinic readings. If the sleeping pressures really go down further, in the middle aged and the elderly, the diastolic coronary filling could go down drastically. Let us remind ourselves that the statistical methods that we have used have served us well in acute infectious diseases set up. The game changes when we come to chronic illnesses. ` Time evolution in a dynamic system is not linear and there are “butterfly effects” happening in this area like in predicting the weather accurately.(5) My experience (experience fallacious, judgement difficult, I know) tells me that we have been predicting the unpredictable using linear statistical methods. Even the controlled studies are flawed to a degree that there are no two individuals alike, although we randomize the groups.
The MRC study did show that to save one patient from stroke we will have to unnecessarily treat nearly 850 people with mild-to-moderate hypertension for five long years with drugs that are not free from side effects when pro-actively looked for.(6)
The important reasons for poor pressure control are also outside the realm of drugs. Multiple drugs make compliance go down exponentially! Life style modifications are not stressed while loading patients with drugs. The so-called primary hypertension is due to the negative feelings in the mind most of the time.(7) If that is not given due importance and set right the results will be the same despite another dozen guidelines. Studies have shown the good effects of meditation and yoga in this area.
There are many other imponderables in this game. One can not put the whole gamut of hypertension care into a water-tight compartment of "Disease Vs Drugs" scenario. Diet plays a vital role. Most preserved foods, including corn flakes and biscuits, have so much salt that could offset drug effects very effectively. Physical exercise is another important factor controlling blood pressure.(8) Drugs would give a false sense of security to the patient that he/she could forget the other rules of the game.
Even our logic that blood pressure is the product of cardiac output and peripheral resistance is flawed as there are no straight blood vessels in the body. The Ohm’s law applies to straight tubes only! That is why beta-blockers that increase the peripheral resistance still reduce blood pressures and alpha-beta blockers are not the panacea for all hypertensives! The unexpected results that have come out of some studies on long term drug use could be due to our faulty linear thinking. Time evolution, what happens to man in future, depends on the total initial state of man-his phenotype, his genotype and his consciousness. Changing the initial state partially need not maintain the effect as time evolves. When one understands this logic everything falls into place in this jigsaw puzzle of hypertension and its control.(9)
It is very easy for pharmacologists to get studies done on small populations and then help write guidelines based on them but, very difficult for practising physicians in real life situations.(10, 11, 12) The more number of tablets the patient gets less is the compliance in real life, unlike in controlled studies. Even controlled studies did, at times, show marginally elevated number of deaths compared to the projected number of deaths, forcing studies to curtail their duration!
Yours ever, Bmhegde
References:
1) Hegde BM. Hypertension-the other side of the coin. Jr. Assoc. Physi. India 1988; 36: 324-330.
2) Fries ED. Effects of treatment on morbidity in hypertension. JAMA 1967; 202: 116-121
3) Andersson OK, Almgren T, Persson B, et. al. Survival in treated hypertensives after two decades follow up. BMJ 1998; 317: 171.
4) Alderman MH. The case for caution in the treatment of mild hypertension. Jr. of Hypertens 1986; 4(suppl V) 5537-5540
5) Firth FR. Chaos-predicting the unpredictable. BMJ 1991; 303: 1565-1568.
6) MRC Working Group: Principal results. BMJ 1985; 291: 97-104.
7) Rozanski A, Blumenthal JA, Kaplan J. Impact of psychological factors in the pathogenesis of cardiovascular disease and implications for therapy. Circulation 1999; 99: 2192-2217.
8) Erol B and Beaglehole R. Exercise for hypertension. Lancet 1993; 341: 1248-1249.
9) Strandberg TE, Salomaa MD, Nukkarinen VA, et. al. Long term mortality after five years multi-factorial primary prevention of cardiovascular diseases in middle aged men. JAMA 1991; 266: 1225-1229.
10) Kopelman RI and Dzau VJ. Trends in treating mild hypertension-a word of caution. Arch. Intern. Med 1985; 14547-49.
11) Bloom BS. Daily regimen and compliance with treatment. BMJ; 2001:323: 647.
12) Schaffer MW. Chaos in living systems. Science 1989; 243: 675-676.
Competing interests: None declared