nos-trum. pronunciation: \nos'-trum\. noun. Etymology: Latin, neuter of noster our, ours.
1. a medicine of secret composition recommended by its preparer but usually without scientific proof of its effectiveness.
2. a usually questionable remedy or scheme.
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Sunday, October 24, 2010

Medical Monitoring At Home A Trend Or False Promise?

It's possible for patients on blood-thinning agents to test their blood at home, but a first look says there's no benefit.

Home testing has arrived and new tests are developed every year.  From pregnancy to genetic defects, an affordable and increasingly simple test is available.  Some visionaries see a time when all patients can care for themselves at home using a Star Trek-type medical scanner. 

Beaming ourselves back up, there's a new study in the New England Journal of Medicine (Oct 21) on the effect of home testing to assess whether blood thinning agents are working properly--to reduce the propensity of blood to form clots in those patients who are at risk for complications.  For example, patients who have mechanical heart valves or atrial fibrillation (a rhythm disturbance that can increase risk of "throwing" clots).

Normally, the patient will come to the clinic or go to a lab to get tested on a regular basis.  Whether in the lab or at home, why is this needed?  It's one of those situations where both too much and too little are dangerous.  If the blood is not thinned enough, clots will form.  If the blood is too thin, then excessive (and potentially lethal) bleeding can occur.

Similar home testing is available  for blood glucose in diabetes.  For most patients home testing can help monitor blood sugar.  The patient can respond to a too-low or too-high blood sugar by adjusting insulin or food intake.  There is consensus that where patients are able to conduct and interpret the testing, this home testing can reduce hypoglycemia and it's opposite, diabetic coma.

For blood thinners, home testing could likewise avert dangerous situations...nip them in the bud before they become a problem.  And reduce wait time and the expense of getting tested elsewhere.

Another plus: for both situations, home testing would be much more convenient.

But whether blood thinners would reduce the complications (excessive bleeding on the one hand, or strokes due to clotting on the other) seems less likely.  Here's part of the data--on mortality.

There's clearly a lack of statistical significance between getting tested in a clinic versus doing it yourself at home (p-value = 0.41).  None of the other markers showed a significant difference (time to stroke, bleeding).  This raises the question of whether home testing is useful for some--or all--conditions for which it could be made available.

Or do we take the opposite tack and say, "It's more convenient, but no worse to test at home, so we should do it"?

The answer depends.  And we don't need a definitive answer to proceed with caution.  Still, I'm bothered that we don't yet have a breakdown by patient subgroups.  It may be that certain patients do improve their lot, while others do more poorly.  That could cause the improvement for some to be hidden in the overall impact.  It's going to take more research.

At this point, I would consider using home testing for that patient who understands the way thinners work, how clotting is a risk, the time frame over which the drugs act, the testing procedure, and when to seek medical attention.

For some patients that's not overwhelming; for others, it could be.

Doc D

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