Tuesday, February 16, 2016

Results of the SPRINT trial

Not sure what the hullabaloo is all about. Some doctors seem to be jubilant that the SPRINT trial shows lower blood pressure than what is currently recommended is better. But I looked at the data and I'm scratching my head.

A general picture of the trial: Participants were non-diabetic hypertensives aged 50 and older. About half (over 4,600) were randomized to therapy that would reduce their blood pressure to less than 140mm Hg. The other half had more intensive pharmacotherapy to get their bp to less than 120mm Hg. The former group averaged 2.8 medications per day, the latter 1.8 meds. Primary outcome was a composite of cardiovascular events including heart attack, stroke, and CV death.

Results: Here's where the rubber meets the road. And frankly the winner zipped past the finish line just a fraction of second earlier than its competitor. Media reported a 25% drop in cardiovascular events in the intensive therapy group. However, the sober truth behind the lurid reporting is that the absolute risk dropped from 2.19% to 1.65% (after 3 years of treatment). That's a measly one half percent. All-cause mortality dropped even lower--just over a third of a percent.

But given the number of hypertensive patients even in the US alone, such a small reduction could potentially prevent a huge number of CV events--even if the data shows that we'd need to give 185 patients an additional pill daily to save one patient from suffering a heart attack, heart failure, stroke, or some other CV event (after a few years of treatment).

But then the trial also discovered a few worms--big ones which should make doctors wary. The NEJM quick take doesn't provide the numbers, but it does tell us that there were more adverse events in the intensive therapy group, events such as syncope (loss of consciousness from hypotension) and kidney failure.

So you have greater benefits, on the one hand, but then greater risks for adverse events as well. So is it really beneficial for hypertensives to bring their bp down to less than 120? Perhaps it would eventually become a judgement call--a decision that doctor and patient will have to arrive at after taking into account the patient's lifestyle, other medical conditions, goals in life, risk aversion level, etc.

Friday, January 15, 2016

2016 USPSTF breast cancer screening recommendations

The latest recommendations are finally out.

I have a beef with its recommendation for the 50-74 age group: They base their decision on the fact that reviews of studies show a decreased breast cancer mortality in those screened. However, the task force clearly knows that screening does not reduce deaths from all causes. They say so right there in their statement: "None of the trials nor the combined meta-analysis demonstrated a difference in all-cause mortality with screening mammography."

What does this mean? Well, apparently screening programs do reduce the number of breast cancer deaths (within a specified time period, eg. per year) but then increases the deaths from other causes, thus nullifying the reduction in the breast cancer mortality. So some women will not die from from breast cancer while others get the short end of the stick and die from something else instead.

So why recommend screening when it does not affect death rates from all causes? Why not underscore this vital information, make certain women know about it, and then have them decide whether they want to go through a screening regimen to reduce their risk of dying from breast cancer but then increase their risk of dying from other causes?

Tuesday, January 5, 2016

"Science has taken a turn towards darkness"

The case against science is straightforward: much of the scientific literature, perhaps half, may simply be untrue. Afflicted by studies with small sample sizes, tiny effects, invalid exploratory analyses, and flagrant conflicts of interest, together with an obsession for pursuing fashionable trends of dubious importance, science has taken a turn towards darkness. 
 --Richard Horton, editor-in-chief of the Lancet 

Similar conflicts of interest and biases [as those in psychiatry] exist in virtually every field of medicine, particularly those that rely heavily on drugs or devices. It is simply no longer possible to believe much of the clinical research that is published, or to rely on the judgment of trusted physicians or authoritative medical guidelines. I take no pleasure in this conclusion, which I reached slowly and reluctantly over my two decades as an editor of The New England Journal of Medicine. 
--Marcia Angell, former editor-in-chief of the NEJM