My two points would be that glucose monitoring should be about supporting the patient centered care more, it informs the patient and then secondarily informs the healthcare provider. And second that asking the wrong questions guarantees the wrong answer. This isn't about glucose monitoring, it is about purposeful and actionable glucose monitoring.
Here are my comments on the questions:
1. What data support glucose monitoring (as distinct from glycemic control) as a means to prevent diabetic macro- and microvascular complications?
First, I would urge an appropriate interpretation of this question. Does “glucose monitoring that is used in an actionable manner” prevent complications? An MRI without appropriate action is totally useless so why would we support the use of glucose monitoring without action. As such, I would argue that any studies of glucose monitoring without action simply not be considered. I realize this will result in most of the studies being thrown out, but they are truly not relevant. Who hears a tree fall in the woods.
And now we get to the problem, there haven’t been sufficient studies of complication outcomes with this question and there is unlikely to ever be good complication outcome studies. All that we will ever have is epidemiological studies and because we have such strong evidence glycemic control is associated with complications we are extremely unlikely to ever be able to divine whether glucose monitor (as distinct from glycemic control) makes a difference. This is frankly a “loaded question” and has been framed in a way that is guaranteed that it cannot be answered affirmatively.
So I would recommend focusing on “actionable glucose monitoring” and accept that glycemic control is a more informative predictor of diabetic complications than will likely every come from what would no doubt be expensive, large and infeasible controlled studies.
- Does frequency of glucose monitoring correlate with better outcomes?
Frequency of glucose monitoring does correlate with better glycemic control, but we do accept that there is a point at which returns diminish and eventually disappear. For insulin dependent diabetics a testing regime in the morning, before and after meals, before driving, with exercise and when hypoglycemia is suspected (probably 6-10 times per day).
- Which patients benefit the most from rigorous glucose monitoring?
Patients that have learned about how to employ glucose monitoring in an actionable manner clearly benefit, those that just test and throw away the readings do not. Learning that carbs raise blood sugars and how to restrict carbs to meet postprandial goals. Measuring blood sugar to achieve proper dosing of insulin. And monitoring blood sugars to maintain patient safety, particularly while driving, exercising and potentially experiencing hypoglycemia
- Does strip accuracy and/or CGM accuracy correlate with better outcomes?
The accuracy is insufficient to support patients that seek tight blood sugar control. Strips are only accurate to +/- 20% under lab conditions and unfortunately under patient use that accuracy is further degraded due to variability in use conditions. A patient that measures their blood sugar at 120 mg/dl (equivalent to an A1c of 6%) can actually have an average blood sugar of 100 mg/dl (an A1c of 5.1%) or 151 mg/dl (an A1c of nearly 7%). If a patient cannot use their meter to differentiate between what we would consider out of control blood sugars and exceedingly tight then we clearly should have little expectation of good outcomes.
2. Can the FDA improve post-approval surveillance of strip/meter/CGM quality?
Post approval surveillance can make a big difference. It will not only assure that strip makers maintain the original accuracy but if done properly it will provide transparency into the ongoing accuracy of strips and allow consumers and practitioners to make informed choices. While it is obvious to patients that meter systems have very different accuracy and performance the current system fails to make that information available and many quite substandard meters and strips are allowed to compete simply on price.
- Does sub-standard glycemic monitoring technology harm patients? If so, what data exist to support such a claim? Are all manufacturers required to report this data to the FDA?
We claim that substandard monitoring harms patients but that only the most egregious errors resulting in death or hospitalization are routinely reported. The vast majority of harm is below that threshold and occurs multiple times each day for the vast majority of patients that employ monitors. Without changes to the current system that harm will not be visible.
- What is the current state of affairs at the FDA in post marketing meter and CGM surveillance?
As a patient, I don’t believe the FDA has yet accepted its role in post marketing surveillance in this area. The CDC has adopted a role with respect to the HbA1c through NGSP and not only has set standards and performs post marketing surveillance, but it makes all that information publicly and readily available which has driven the accuracy for the HbA1c test from +/- 15% to below +/-7%, s significant achievement. Unfortunately the CDC has not regulatory authority. There is no reason the FDA (and/or the CDC) could not do the same for glucose monitoring.
- What enforcement options are available to the FDA and how are they implemented?
The FDA could withdraw approval for meters/strips that repeatedly fail to meet criteria.
3. Does current Medicare policy balance the need to provide patient access to high quality care and effective glucose monitoring and to control program costs and, if not, what policy changes are needed with respect to:
Current Medicare policy fails to establish reasonable levels of quality, accuracy and performance for glucose monitoring supplies. This is mostly a problem with meters where sub-standard meters have almost universally been selected based simply on cost. Medicare itself should institute a minimum set of quality/accuracy standards and probably institute its own surveillance program
a. Patient Access to BGMS supplies under the Competitive Bidding Program (medical necessity attestation and other paperwork requirements for physicians’ offices vs. potential fraud and abuse, access to blood glucose test strips that are accurate and reproducible)
b. Patient access to CGM technology (access by appropriate patients)
4. What is the most effective way for the key stakeholders to achieve equitable, evidence-based, cost-effective regulation of glucose (blood, continuous) monitoring technology?
Ask the right questions. All glucose monitoring should be actionable and in the vast majority of the cases those actions are “patient actions.” Don’t ask the wrong question about what a health practitioner will do with glucose monitoring data, the answer is usually nothing.
And unless the government wishes to spend a long time and a huge amount of money studying long term outcomes it would be better to simply accept what we learned from the DCCT. Achieving better glycemic control reduces complications. Period. If actionable use of glucose monitoring improves glycemic control we should accept that it will also reduce complications.
