Tuesday, June 3, 2008

USPSTF: Blood Pressure Trumps Blood Glucose & the Implications for Diabetes and Hypertension Disease Management

Persons with blood pressure readings consistently greater than 135/80 should be screened for diabetes mellitus every three years, or so says the U.S. Preventive Services Task Force. When this headline first crossed the Disease Management Care Blog’s twin flat screen monitors, it thought the rationale was simple.

A high prevalence of undiagnosed diabetes among persons with hypertension should be the cause for alarm. Diabetes mellitus is present in about 9% of the U.S. population, its prevalence increases to more than 20% among persons aged greater than 65 years and is also associated with a high body mass index. Since these risk factors tend to cluster together, it makes sense to look for the condition, right? Earlier diagnosis would lead to earlier treatment and prevention of the complications of diabetes, right?

That’s not the case. Instead, the USPSTF logic is reversed and twofold. The first is that the presence of diabetes alters the preferred blood pressure to less 135/80, even if it means starting a lifetime of daily pills. The second is that it makes a difference as to which medicines are used. So it’s not a matter of diagnosing and then treating diabetes, it’s a matter of managing the blood pressure differently.

Don’t be surprised. Several studies including the U.K. Prospective Diabetes Study (UKPDS) and the Hypertension Optimal Treatment (HOT) Study demonstrated a strong link between blood pressure control and macrovascular complications, such as heart attack and stroke, among persons with diabetes. Up to 80% of persons with diabetes will die of macrovascular disease, so blood pressure control is a priority. In fact, it is probably more important than blood glucose control. To give you a sense of this, the very valuable “Number Needed to Treat” (NNT) blood pressure calculation, provided in this excellent Annals article, is an impressive 23 or less for all cause mortality, stroke or heart attack over ten years. Thiazide diuretics or ACE inhibitors (and frequently both, combined with other medications if necessary) should be used initially, versus other first line agents.

Note that there are no prospective studies that show control of the blood glucose level in diabetes changes the incidence of heart attack or stroke. Rather, blood sugar control is correlated with fewer “microvascular” complications, such as damage to the sensory nerves in the feet or kidney disease.

The DMCB wonders how this new recommendation would work for physicians in primary care settings:

Scenario 1: During the course of every one-on-one visit with patients, the physician tries to remember that a blood pressure reading that normally isn’t considered “high” should prompt a check of those past blood tests in the back of the chart and to order a screening test for diabetes, in addition to all the other things that need to fit into a 15 minute office visit. If really well organized, have a flow sheet in the front of the chart. Anyone without an appointment loses out.

Scenario 2: Have a standing order for the office nurse to review the charts’ labs and arrange for a screening test for diabetes if, during the course of the intake, the blood pressure is more than 135/80. Anyone without an appointment loses out.

Scenario 3: During the course of every one-on-one visit with patients, the physician gets annoying prompts from that new EHR that a blood pressure reading that normally isn’t considered “high” is high and a lack of any labs under the 'results' tab should prompt an order for a screening test for diabetes click here, in addition to all the other aspirin, cholesterol screening, mammogram and immunizations prompts – click heres that clutter the screen during the 15 minute office visit. Anyone without an appointment loses out.

Scenario 4: Physician fires up that new and improved EHR registry and uses some if-then branching programming logic to extract everyone with a mean of > 135 OR >80 over three visits in the two BP fields AND absent diagnosis of diabetes (look up the ICD 9) codes AND absent qualifying blood test over the last 365 days x2. Generate form letter to all patients meeting criteria and “blow in” the name and address from the demographic data fields. Blow in a screening lab order on hundreds of patients. The physician and the office staff deal with each one at a time when patients start calling with questions and when the physician needs to actually see the folks with evidence of diabetes.

Scenario 5: Physician tells the office manager or nurse to deal with Scenario 4. They tell the physician (s)he needs to contact the EHR vendor and find out how much it will cost to have this ad-hoc programming done.

Scenario 6: Physician awaits the arrival of a newly developed HEDIS measure for the number of persons with blood pressure > 130/85 (denominator) who have a screening blood glucose level (numerator). (S)he resists the flaky letter from the managed care organization listing patients, many of whom are not recognized, that the MCO believes meet criteria for measurement or intervention so that they can get NCQA accreditation. There is a change of mind when the flaky letter Ver. 2 outlines the terms of a new P4P initiative linked to this measure.

Scenario 7: The physician discusses this with the Medical Home trained staff and instructs them to work with the disease management vendor, who has the mojo to contact everyone meeting criteria after they’ve remotely accessed the electronic patient files in a HIPAA compliant way. Patients meeting criteria are contacted with letters, IVR and eventually live nurses who remotely arrange testing. Patients who have the labs done have been coached, and those with a fasting blood glucose > 126 (have diabetes) and a blood pressure > 135/80 are seen by your Medical Home staff and medications are started and adjusted using a standing order protocol that is safe and effective. Physician is in the meantime seeing sick people, but available if the protocol isn’t working.

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