Subjective vs Objective Clinical Data: BP Edition

Feb 06 2015 Published by under [Medicine&Pharma]

In medicine, we collect several types of data about patients and their problems. Some is subjective, the stuff the patient tells us - what hurts, where, and why. Then there are the objective findings from our exam and tests.

Guess which type of data we trust most?

Of course, there is another category now of objective data collected by the patient via home monitoring devices. Some of these data are recorded by the device and downloaded into our systems, making patient fabrication or manipulation very difficult. Values written by the patient into a log may not be exactly what the device said.

Before glucose meters had recording capabilities, we all saw patients who never had a reading above 140 but their Hb A1c ran 10% (Hb A1c is a measure of glycated hemoglobin and reflects the average blood sugar reading for the prior 3 months). Now meters have memory; some even have connectivity so they can alert care providers of developing problems.

We need to address these issues for blood pressure measurements.

We have the ability to measure blood pressure around-the-clock, the 24 hour ambulatory blood pressure monitor (ABPM). This provides the gold standard for on-the-hoof blood pressure readings, and we know that our office reading often run high (from white coat hypertension) or may be more normal than the patient (masked hypertension). Readings done at home, work, or school often reflect the patient's true blood pressure better than our office readings, at least under controlled study situation.

But then there are those pesky human issues.

When someone hands me a log book and every reading is 120/80 with no variation, I have a hard time suspending disbelief. Patients want to please their providers most of the time, even though having hypertension can be bad for them. As payors begin to audit our records and reward us for quality of care, we get little notes about things we should respond to: have you considered monitoring complication X? Have you started this drug?

I'm waiting for the one about the hypertensive reading in my office with a patient who has normal outpatient readings. After all, the only blood pressure I can really guarantee was done correctly and recorded accurately is the one in my office.

My own blood pressure cuff sends its reading directly to my smartphone. I can send values to my provider from there, adding a level of objectivity to the process. However, not everyone can afford this cuff and a smartphone. We need an automatic cuff system with the connectivity built in at an affordable price point.

While we're at it, ABPM capabilities would also be sweet. How much trouble could it be to have an option in the app to take blood pressure at intervals for a 24 hour period and then send it to a provider? Even with great monitoring, my patients cannot check their pressure during sleep.

So how about it, health tech firms? In this brave new world of wearables can we have better blood pressure monitoring at a lower price?

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