Commercial motor vehicle (CMV) drivers with moderate to severe obstructive sleep apnea (OSA) continue to face a significantly elevated risk of major crashes that result in serious injuries and fatalities. Yet medical examiners are often placed in a difficult position: how do we accurately identify drivers at risk for OSA while ensuring that medically qualified drivers receive their certification without unnecessary barriers?

This tension has only grown as new research highlights a critical flaw in the way OSA risk has traditionally been screened.

Over 90% of CMV Drivers With OSA Deny Excessive Daytime Sleepiness

For decades, subjective tools—especially the Epworth Sleepiness Scale (ESS)—have been used as a first line screening method for OSA. But the assumption behind these tools is now being challenged.

According to a 2024 nationwide study published in Sleep Medicine by Tanigawa et al., involving 19,699 commercial truck drivers, more than 90% of drivers with OSA did not report excessive daytime sleepiness. This means the vast majority of high risk drivers appear “normal” on subjective screening alone.

The study found:

• ESS had very poor sensitivity (0.10) for detecting moderate to severe OSA
• ESS had high specificity (0.93) — meaning drivers who did report sleepiness were likely truthful
• Adding BMI ≥25 improved sensitivity to 0.48, but still missed over half of high risk drivers
• The strongest screening combination was BMI ≥25 plus OSA related signs, yielding 0.77 sensitivity

Even then, adding subjective sleepiness did not improve detection.

The conclusion was clear: self reported sleepiness is not a reliable tool for identifying OSA in CMV drivers.

Why Subjective Tools Fail in This Population

The study reinforces what many examiners already observe in practice:

• Drivers often normalize fatigue
• Many fear job loss and underreport symptoms
• Cultural and workplace pressures discourage admitting sleepiness
• ESS relies on self awareness, which varies widely
• Some drivers with severe OSA genuinely do not perceive themselves as sleepy

This creates a dangerous mismatch between actual physiological risk and self reported symptoms.

The Stakes Are High: OSA and Crash Risk

Untreated OSA is associated with:
• Impaired vigilance
• Slower reaction times
• Microsleeps
• Up to a seven fold increase in crash risk

The study cites longstanding evidence that OSA contributes to a significant portion of motor vehicle crashes, with enormous human and economic costs.
For medical examiners, this means that relying on subjective tools alone is not only ineffective — it may unintentionally certify drivers who are at high risk for catastrophic fatigue related crashes.

Where Does This Leave Certified Medical Examiners?

Not every driver needs a sleep study. Not every driver with a high BMI has OSA. And sleep studies can be expensive and are often not covered by insurance.

But medical examiners still have a duty to:
• Apply FMCSA medical standards
• Protect public safety
• Make evidence based decisions
• Use objective indicators when subjective tools fail

FMCSA guidance allows examiners to certify drivers with OSA only when treatment is effective, symptoms are resolved, and compliance is demonstrated. Drivers treated with CPAP must show:

• At least 1 month of compliant use
• 4 hours per night, 70% nightly usage (MRB recommended standard)
• Resolution of apneas confirmed by repeat testing
• Annual objective sleep study testing
• Continuous, uninterrupted therapy

Drivers treated surgically must complete a 3 month symptom free waiting period.

Examiners may issue a 90 day certificate when a driver is suspected of OSA or has a diagnosis but has not yet completed testing or treatment.

FMCSA also notes that when a driver presents with multiple OSA risk factors—typically interpreted as three or more—the medical examiner should consider referral for objective sleep apnea testing.  Source: https://www.fmcsa.dot.gov/advisory-committees/mrb/final-mrb-task-16-01-letter-report-mcsac-and-mrb

Symptoms Associated With Sleep Apnea Include (but are not limited to):

• Loud snoring
• Episodes of apnea during sleep
• Gasping for air during sleep
• Awakening with a dry mouth
• Morning headaches
• Insomnia or fatigue
• Excessive daytime sleepiness (when present)
• Difficulty paying attention while awake
• Unintentional sleep episodes during wakefulness

Some Risk Factors That May Be Associated With OSA

• Hypertension (treated or untreated)
• Type 2 diabetes
• History of stroke, coronary artery disease, or arrhythmias
• Rheumatoid arthritis
• Hypothyroidism (untreated)
• Micrognathia or retrognathia
• Loud snoring
• Small airway (Mallampati Class III or IV)
• Neck size >17" (male), >15.5" (female)
• Age >42
• Male sex or post menopausal female
• BMI ≥33

Note: A high BMI alone may not be sufficient to order a sleep study. The ME should exercise sound clinical judgment on a case by case basis.

A More Accurate, Fair, and Ethical Path Forward

This research does not call for over testing or unnecessary burdens on drivers. Instead, it calls for better tools, better judgment, and better alignment with real world risk.

For medical examiners, this means:

• Recognizing the limitations of subjective sleepiness
• Using objective indicators more confidently
• Referring for home sleep apnea testing when appropriate
• Documenting clinical reasoning clearly
• Balancing fairness to drivers with responsibility to public safety

Ultimately, the goal is not to disqualify drivers — it is to identify risk early, support treatment, and keep drivers healthy and safe on the road.

References

1. Tanigawa, T., Wada, H., Nakano, H., Sakurai, S. (2024). Self reported sleep tendency poorly predicts the presence of obstructive sleep apnea in commercial truck drivers. Sleep Medicine, 115, 109–113. https://doi.org/10.1016/j.sleep.2024.02.014

2. Federal Motor Carrier Safety Administration (FMCSA). Obstructive Sleep Apnea (OSA) – Driver Medical Requirements. Retrieved from FMCSA website.

3. FMCSA Medical Review Board (MRB). (Task 16 01). Final MRB Letter Report to MCSAC and MRB: Obstructive Sleep Apnea (OSA) in Commercial Motor Vehicle Drivers. Available at: https://www.fmcsa.dot.gov/advisory-committees/mrb/final-mrb-task-16-01-letter-report-mcsac-and-mrb

4. 49 CFR §391.41(b)(5). Physical Qualifications for Drivers — Respiratory Dysfunction Standard.

5. American Thoracic Society (ATS). (Guideline referenced in Sleep Medicine article). Sleepiness and Driving Risk in Commercial Drivers.

6. American Academy of Sleep Medicine (AASM). Clinical Practice Guidelines for the Evaluation, Management, and Long Term Care of Obstructive Sleep Apnea in Adults.

With the rising use of Glucagon-like Peptide-1 (GLP-1) receptor agonists in patients with Type 2 Diabetes Mellitus (T2DM) and obesity, certified medical examiners (CMEs) are increasingly likely to encounter commercial motor vehicle (CMV) drivers prescribed these medications. This blog explores the therapeutic role of GLP-1s, their potential side effects, and the implications for driver safety and medical certification.

Clinical Role of GLP-1 Receptor Agonists

GLP-1s are antidiabetic agents used to:

• Improve glycemic control in T2DM as an adjunct to diet and exercise.

• Support weight loss in patients with obesity, including those with obstructive sleep apnea (OSA).

• Reduce cardiovascular risk (e.g., myocardial infarction, stroke, cardiovascular death) in adults with T2DM and established cardiovascular disease.

• Slow the decline in estimated glomerular filtration rate (eGFR) in patients with T2DM and chronic kidney disease (CKD), potentially delaying progression to end-stage renal disease.

Common GLP-1 Agents

Zepbound, in particular, may benefit drivers with moderate-to-severe OSA and obesity, as weight loss can improve sleep apnea symptoms and metabolic rate.

Adverse Effects and Safety Concerns

GLP-1s are generally well tolerated, but potential side effects include:
• Gastrointestinal issues: nausea, vomiting, diarrhea, abdominal pain, dyspepsia
• Gallstones (cholelithiasis), sometimes requiring cholecystectomy
• Muscle wasting, weight loss, hair loss
• Post-marketing reports: acute pancreatitis, necrotizing pancreatitis, acute kidney injury, dizziness, and rare fatalities.
• Dehydration and Hypotension
• Severe hypoglycemia—especially when combined with other antidiabetic agents

Black Box Warning

GLP-1s carry a warning for potential thyroid C-cell tumors, including medullary thyroid carcinoma (MTC). They are contraindicated in individuals with a personal or family history of MTC or multiple endocrine neoplasia syndrome type 2. In January 2024, the FDA also reviewed reports of suicidal ideation and behavior associated with these agents.

Certified Medical Examiner (CME) Guidance

When evaluating a CMV driver prescribed GLP-1s, CMEs can consider the following:

• Obtain a thorough medical history: Confirm the diagnosis (T2DM, obesity, OSA), medication regimen, and any side effects that may impair safe driving.

• Conduct a comprehensive physical exam: Assess for comorbidities such as cardiovascular disease, retinopathy, renal disease, or neuropathy that may disqualify the driver.

• Request medical clearance: The treating provider should confirm the diagnosis, dosage, and safety of treatment, and understand the physical and mental demands of CMV operation.

• Use FMCSA Form MCSA-5895 (optional): This form can help document provider clearance for medications of concern.

• Educate the driver: Emphasize hydration to reduce the risk of acute kidney injury and monitor for rapid weight loss, which may cause hypoglycemia or hypotension.

• Review labs if needed: While not required, CMEs may request metabolic panels and HbA1c levels to assess stability and safety.

As the use of GLP-1 receptor agonists continues to expand, certified medical examiners must remain vigilant, informed, and compassionate in their evaluations. These medications offer powerful benefits for managing chronic conditions, but they also carry risks that can directly impact a driver’s ability to operate a CMV safely.

By combining thorough clinical assessment with thoughtful collaboration between examiners and treating providers, we can uphold both public safety and patient dignity assuring that every driver is evaluated with care, respect, and evidence-based insight.

References: https://emedicine.medscape.com/article/123702-overview

NRII Implementation Deadline

The Federal Motor Carrier Safety Administration (FMCSA) has set June 23, 2025, as the official compliance date for the National Registry Integration Initiative (NRII). However, states may implement NRII earlier if they are prepared. Once a state integrates NRII, medical certification information for Commercial Learner's Permit (CLP) applicants and Commercial Driver’s License (CDL) holders will be electronically transmitted from the National Registry to the State Driver Licensing Agency (SDLA). In such states, the paper Medical Examiner’s Certificate (MCSA-5876) may no longer serve as valid proof of medical certification.

Key Changes Effective June 23, 2025

Several important modifications will take place:

• FMCSA will electronically transmit medical examination results (qualified, unqualified, and voided) for CLP applicants and CDL holders to the SDLAs.
• FMCSA will transmit medical variance information (medical exemptions and Skill Performance Evaluation (SPE) certificates) electronically to the SDLAs.
• SDLAs will update CDL Information System (CDLIS) driver Motor Vehicle Records (MVR) with examination results and restrictions.
• Medical examiners will no longer issue paper certificates (MCSA-5876) to CLP applicants or CDL holders.
• CLP applicants and CDL holders will no longer need to submit paper certificates to their SDLAs.
• Motor carriers must verify medical certification electronically through the CDLIS driver MVR instead of using paper Medical Examiner’s Certificates.

Medical Variances

If a medical examiner determines that a driver requires a medical variance, such as an SPE Certificate or medical exemption, the driver’s examination results will not be transmitted to the SDLA until FMCSA issues the variance. Once obtained, the National Registry system will link the variance with the original examination results and transmit them to the SDLA. Despite electronic transmission, drivers must still carry proof of medical variances while operating.

Ensuring Your Medical Certification is Posted to Your Record

Since drivers do not have direct access to the National Registry or SDLA systems, errors in transmission may occur. If a driver receives a CDL downgrade letter despite having completed a physical qualification exam, their medical certification was not received by the SDLA. Follow these steps to resolve the issue:

1. Contact the medical examiner who conducted your exam and ask them to verify if an error message was received regarding your certification.
2. Contact your SDLA to confirm whether the corrected medical certification was posted.
3. If the issue persists, reach out to FMCSA’s National Registry Technical Support Helpdesk at This email address is being protected from spambots. You need JavaScript enabled to view it. or (617) 494-3003.
If stopped by law enforcement and informed that you are not medically certified, follow the same steps immediately to correct the issue.

Non-CDL Holders

If you do not hold a CDL, NRII does not apply to you. Medical examiners will continue to issue the paper Medical Examiner’s Certificate (MCSA-5876) as proof of medical certification, and you must carry it while operating a commercial motor vehicle. However, if you later obtain a CDL, the SDLA can retrieve your existing certification information from the National Registry and post it to your CDLIS driver MVR.

On November 18, 2024, FMCSA published the attached technical amendment final rule that amends 49 CFR 391.49(d)(3)(i)(B) and (d)(3)(ii)(C) to clarify the meaning and effect of the current requirement that individuals with upper limb loss or impairment must be capable of demonstrating precision prehension and power grasp prehension to be eligible for a skill performance evaluation (SPE) certificate issued by FMCSA. The amendments clarify that a functioning hand is necessary to demonstrate precision prehension and power grasp prehension and that a prosthesis is required if the applicant does not have a hand. The amendments also clarify when an applicant has upper limb impairment that a prosthesis or orthotic device is required if the applicant is not capable of demonstrating precision prehension and power grasp prehension with each hand separately without a prosthesis or orthotic device.

Specifically, paragraphs (B) (for limb loss) and (C) (for limb impairment) relating to the statements made by the physiatrists and orthopedic surgeons in the medical evaluation summary have been amended to read as follows:

(B) A statement by the examiner that the applicant is capable of demonstrating precision prehension (e.g., grasping and manipulating knobs and switches using the fingers/thumb) and power grasp prehension (e.g., grasping, holding, and maneuvering the steering wheel using a hand) with each hand separately. Prior to applying for an SPE certificate, an applicant with loss of a hand or arm must be fitted and proficient with a proper prosthesis that enables the applicant to demonstrate precision prehension and power grasp prehension with each hand separately. This requirement does not apply to an individual who was granted a waiver, absent a prosthetic device, prior to January 6, 1986, the effective date of the requirement.

(C) A statement by the examiner that the applicant is capable of demonstrating precision prehension (e.g., grasping and manipulating knobs and switches using the fingers/thumb) and power grasp prehension (e.g., grasping, holding, and maneuvering the steering wheel using a hand) with each hand separately. Prior to applying for an SPE certificate, an applicant with upper limb impairment must be fitted and proficient with a proper prosthesis or orthotic device, if the applicant is not capable of demonstrating precision prehension and power grasp prehension with each hand separately without a prosthesis or orthotic device. This requirement does not apply to an individual who was granted a waiver, absent an orthotic device, prior to January 6, 1986, the effective date of the requirement.

In addition to the attached technical amendment final rule, FMCSA has also attached information outlining prevalent issues present when MEs are documenting evaluation outcomes of limb loss and impairment under 49 CFR 391.41(b)(1) and (2) during the physical qualification examination. These errors require FMCSA to void the examinations and require the drivers to obtain a new examination. FMCSA requests that all MEs review this information closely to ensure that examinations are recorded in accordance with the Federal Motor Carrier Safety Regulations.

Alternative Physical Qualification Standards for the Loss or Impairment of Limbs

Skill Performance Evaluation (SPE) Certificate Issues

Any medical professional seeking to become certified to conduct examinations on potential commercial vehicle drivers should be familiar with the role of a Medical Expert Panel (MEP).