COMMENTARY

Optimal Home Glucose Testing: Sometimes Less Is More

Richard M. Plotzker, MD

Disclosures

January 31, 2019

In my decades of practice, only once has a patient stolen something from my exam room. A patient with diabetes in his prime years came for a follow-up. We spoke about his progress since his last visit, a history that left me uncertain. I could not tell what medicine he took and his symptoms were vague.

I took out my Tracer II meter, the first mass-marketed, reasonably affordable testing system to those with steady incomes. Insurance coverage at the time did not mandate testing supplies, which were the most costly elements of daily diabetes care for most patients in the mid-1990s.

I checked his capillary glucose, told him what it was, replaced the meter and remaining strips into their usual place in my top left drawer, and then went on with the encounter. I made a decision, went to my sample closet, escorted the fellow to the front desk, and started with the next patient.

She would also benefit from a spot check, mainly to show her how to do it. On opening the drawer, I saw that the meter and 25-strip container were gone. I did not pay for these; company representatives were eager to give me a supply of machines, so a trip to the closet provided a new machine.

I tested the patient, gave her the machine (which included 10 strips in the kit) and a prescription to get more, and opened another glucose testing kit for my office use.

People want this testing capacity but have misgivings about the cost. Theft is rare. Conservation of supply and testing less often than advised is common, and not necessarily medically wrong.

Is Home Glucose Testing Worth It?

As a trainee of the late 1970s, I had been a prescriber of insulin and sulfonylurea before home blood monitoring became available. Urinary glucose testing guided insulin dosing on hospitalized patients, best guess and lab glucoses on office patients.

The A1c had already become available to serve as a scorecard, but the emergence of blood glucose testing at will—initially by color changes at the end of a strip, then eventually the digital display of the devices that we use now—transformed decision-making in diabetes care.

In the hospital, urines were double-voided before meals and at bedtime, so blood testing could be done just as easily. It was expensive and absorbed some nursing time, but $3 per day to do glucose testing never got a peep from the accountants.

At home, however, $3 per day every day would add up to about a typical monthly car payment at that time. Patients wanted to do what the doctor said, but between schedule disruptions, carrying equipment when they went to work or out to eat, sore fingers, and less money for pizza, patients and doctors reached a similar conclusion very quickly: Some people benefited from testing more than others.

Murky Standards

Not everyone should test four times a day, even if that's what they do in the hospital or the diabetes educator says they should. Later, states mandated what insurers must cover, which for my state and most others included home glucose testing for established patients with diabetes.

Medicare set its standard of three tests per day for insulin users and once per day for non–insulin users, with the ability of the physician to add to the monthly allotment for medical cause. That has remained the standard, but whether a person takes insulin or not may not be the best medical criterion for assessing testing frequency.

From the outset, home glucose monitoring has been an important resource, prescribed in some form to all people with diabetes taking medication. Considering the magnitude of this investment in optimal diabetes care—and its availability for 35 years—the standards of ideal prescribing are still murky.

'Prescription Anarchy'

A recent essay[1] in JAMA Internal Medicine looked at claims data for purchasing test strips by non–insulin users, and found that testing averaged about twice a day, with no risk for hypoglycemia.

Reference was then made to the recommendation from the American Academy of Family Physicians—aimed at promoting more cost-effective diagnostic and therapeutic prescribing—that patients with diabetes who are stable and whose medicines do not risk hypoglycemia can forgo daily testing.

Amid these organizational recommendations, we are left with a form of prescription anarchy. Testing recommendations need to be simultaneously individualized and purposeful.

My view may be distorted by referral patterns that select out the more difficult diabetic challenges, but the presence or absence of insulin therapy may not be the best way to determine testing frequency and timing, even though the simplicity of collecting that data in this era of computerized claim records makes this analysis expedient.

Examine Your Goals

A better starting point might be to ask: Why do self-monitoring at all? Diabetes care requires a mix of goals. Some are very long-term, such as averting retinopathy, and some are intermediate, such as having a successful pregnancy or trouble-shooting an unexpectedly high A1c or lab glucose in someone who seems to be doing well.

Other uses are more immediate, such as in people having bariatric surgery whose postoperative diabetes care program is likely to change dramatically, or when assessing whether introduction of a new medicine served its intent.

And with our currently available medicines, home testing can be invaluable at finding dawn phenomenon patterns, postprandial hyperglycemia, or other daily patterns that would suggest that other medication options might improve the status quo.

Patients may be tested four times daily for weeks at a time as part of the admission orders.

Let's not forget about inertia, either. We have protocol medicine that allows physicians and systems to process people through. In the hospital, that means before-meal and bedtime monitoring and 2 units of insulin aspart poked through the skin four times daily, even though the blood glucose never reaches 200 mg/dL.

Copy & paste the prevailing orders for transfer to rehab or nursing homes, and this excessive care can continue without end. In a hospital's psychiatric unit, where psychotropic medicines frequently contribute to hyperglycemia and where patients often stay much longer than elsewhere in the hospital, patients may be tested four times daily for weeks at a time as part of the admission orders. They might get no medicine, and certainly not a reduction in glucose surveillance as their stability declares itself.

From time to time, I have tried to reduce the frequency of testing, only to be declared disruptive by those who think that assigned times for everyone results in fewer errors, with the benefit of not having to think about who needs to be tested and treated at individually determined times.

Mass Protocols Don't Work

Most diabetes care, though, takes place when patients have their usual diet and activity, with periodic scheduled assessments at 3- to 6-month intervals. Additionally, the ones who transition from the primary doctor to the endocrinologist typically have specific problems to solve.

Some decisions look straightforward. Therapeutic A1c without progression, good medicine tolerance, stable spot checks on home monitoring, availability of more testing for sick days, and no sulfonylureas or insulin to add hypoglycemia risk all require minimal home testing but up-to-date lab testing.

People with less favorable lab results deserve a solution, which are best achieved by knowing when the highs and lows of their glucose excursions occur. They not only need more frequent home glucose testing but guidance on which times of their daily meals or exercise schedule need to be targeted. You cannot mass-protocol that type of a problem because there are too many variants.

Unfortunately, we don't have a reliable answer to testing frequency. Excessive testing is often obvious, but attempts to reduce this in an institutionalized patient are much more difficult than a private agreement between doctor and patient in the office.

So, as the authors of the JAMA Internal Medicine op-ed acknowledge, the amount of testing done exceeds its demonstrated benefit. Where and how to economize may not be quite as easy as they suggest.

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