First in a series
A PRACTISING PHYSICIAN realizes sooner than he could finish his first year of clinical practice that Medicine is such a humbling profession. It is a very dynamic science with the ordinary physician being deluged with new clinical data much more than he could assimilate and translate to good use in his clinical practice.
To resolve this problem, expert bodies convene regularly to review all new data, especially from landmark researches and clinical trials, and use these as the basis for treatment guidelines for practising physicians. These treatment guidelines are used as a reference in clinical practice to guide physicians on how best to manage their patients with similar cases described in the guidelines.
The treatment guidelines published by various expert bodies appear to be a practical reference and practice aid for all physicians. It is supposed to be based on hard data or accurate scientific evidences from landmark clinical trials and other researches, reinforcing an evidence-based clinical practice.
But there are instances when hard clinical data are not available, and one can?t help but think that some parts of these internationally circulated treatment guidelines are based on expert opinion or what the members of these expert panels believe as best standard of care. I jokingly call this as eminence-based medicine. One can therefore expect that in many instances, some of these expert opinions are subsequently proven wrong by well-conducted researches.
One such case is the treatment guidelines on how aggressive blood pressure (BP) lowering should be in diabetics.
Most guidelines advocate a more aggressive BP-lowering in diabetics targeting a BP of less than 130/80 mmHg. The American Diabetes Association (ADA) even released a position statement saying that ??there is no threshold value for BP, and (cardiovascular) risk continues to decrease well into the normal range.? The implication is that the lower the BP up to a level of around 115/75 mmHg or even slightly lower, the better for the patient. I plead guilty that I have also advocated this line of thinking in all my lectures on the subject.
Because of this aggressive approach in BP lowering for diabetics, several treatment guidelines from reputable international organizations recommend starting BP-lowering drug therapy at low BP levels like 130/80 mmHg if there?s diabetes, or even lower, say 120/80 mmHg if there?s established heart, brain or kidney disease.
For quite sometime, the guideline advocating aggressive BP-lowering in diabetics was well accepted and practiced. Everyone believed it was well founded, or so everyone thought. Every physician appeared convinced that the lower the BP in hypertensive diabetics to as low as 110-115/70-80 mmHg, the better for the patient. Looking back though (and it?s always easier to analyze things in retrospect), hard data supporting a systolic BP (the upper number in a BP reading) less than 130 mmHg was lacking particularly in diabetics with concomitant narrowing of the arteries.
Two new clinical researches presented in the American College of Cardiology Congress in Atlanta two months ago stirred the hornet?s nest. The first paper is the Accord (Action to Control Cardiovascular Risk in Diabetes) trial which showed that there was no difference in the reduction of cardiovascular risk in high-risk diabetic patients if the systolic BP was brought down with drug therapy to a moderate level of less than 140 mmHg or a more aggressive level of less than 120 mmHg. Aggressive BP-lowering required more drugs to be used by the patient, higher cost of treatment and more side-effects.