Diabetes and the Commercial Motor Vehicle Driver
The physical exam should focus on identifying signs of complications from diabetes, such as retinopathy, nephropathy, or peripheral neuropathy. At each certification visit, the examiner should assess the patient’s height and weight, BMI, vision, hearing, blood pressure, and heart rate, and perform urinalysis to screen for proteinuria or glycosuria. A fingerstick test to obtain a random blood glucose reading is often performed in a driver with glycosuria.
Likewise, the A1C level should be documented in every patient with new-onset or known diabetes, with the recommendation from the FMCSA that a level >10% is an indicator of poor glucose control.7 It is important to note that an A1C level up to 10% is not the glycemic target recognized by the American Diabetes Association and the American Association of Clinical Endocrinologists. The FMCSA is focused more on hypoglycemic concerns than on providing management guidelines.
DETERMINING CERTIFICATION
Currently, the recertification time recommended for CMV drivers with diabetes and documented glucose control is 1 year. This is based on the assumption that the driver is under medical care with a treatment plan and that he/she is not currently experiencing any complications from the disease. Furthermore, insulin secretagogues (eg, sulfonylureas) can be used for glucose control as long as adverse effects (eg, hypoglycemia) do not interfere with safe driving. However, the FMCSA does not recommend certifying any driver who
- In the past 12 months has experienced a hypoglycemic reaction resulting in seizure; loss of consciousness; need of assistance from another person; or period of impaired cognitive function that occurred without warning.
- In the past 5 years has had recurring (≥ 2) disqualifying hypoglycemic reactions.
- Has received a formal diagnosis of peripheral neuropathy, loss of position, or pedal sensation.
- Has resting tachycardia or orthostatic hypotension.
- Has severe diabetic nephropathy requiring dialysis.
- Has severe nonproliferative or proliferative retinopathy.8
In drivers with new-onset hyperglycemia, it is appropriate for the medical examiner to refer the driver to his/her primary care provider for further testing (eg, A1C), determination of treatment, a copy of the diabetes medical standard for driving, and written opinion of the driver’s medical fitness for duty. Subsequently, the medical examiner can utilize this information from the primary care provider to determine certification for the driver. While there are no specific guidelines on the waiting period for certification, the driver should demonstrate glucose control with treatment that is adequate, effective, safe, and stable.7
Overall, while living with diabetes can be challenging, patients who demonstrate control of the disease can maintain their occupation as a CMV driver. The role of the medical examiner is to evaluate the driver’s risk to safely operate a CMV—in particular, considering the possibilities of a severe hypoglycemic episode or target organ dysfunction—whereas the clinician treating the driver’s diabetes is focused on minimizing the complications associated with hyperglycemia.
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