The Time is Now: Let's Bring Pharmacogenomics (PGx) into Geriatric Care

The Time is Now to Bring Pharmacogenomics (PGx) into Geriatric Care

As medicine moves toward a more personalized approach, pharmacogenomics (PGx) is emerging as a key player in geriatric care. For clinicians treating older adults, understanding the genetic factors that influence drug response can be crucial to improving outcomes, minimizing adverse effects, and enhancing quality of life. Here’s a closer look at what you need to know about integrating PGx into geriatric care.

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1. Why PGx is Essential for Older Adults

Older adults are often more susceptible to adverse drug reactions (ADRs) and treatment failures. The natural physiological changes with age—such as reduced liver and kidney function—already impact drug metabolism. When we add genetic variability into the mix, we see a clear opportunity to improve the safety and efficacy of treatments. PGx testing identifies genetic factors that influence how medications are processed, helping clinicians avoid a "one-size-fits-all" approach.

Key takeaway: PGx allows us to optimize medication choice and dosing, reduce ADRs, and avoid the trial-and-error approach often seen in geriatric prescribing.

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2. Key Drug-Gene Interactions in Geriatric Care

Certain gene-drug interactions are especially important in geriatric patients, who commonly take medications for cardiovascular disease, mental health, and chronic pain. Here are a few critical interactions:

• CYP2C19 and Clopidogrel: Some individuals metabolize clopidogrel poorly due to CYP2C19 variations, resulting in lower antiplatelet activity. For these patients, alternatives like ticagrelor may be more effective.
• SLCO1B1 and Statins: Variants in SLCO1B1 can increase the risk of statin-induced myopathy. For high-risk patients, lower doses or alternative statins may be appropriate.
• VKORC1 and CYP2C9 with Warfarin: Variants in VKORC1 and CYP2C9 affect warfarin sensitivity, potentially increasing bleeding risks. PGx can guide dosing to ensure safer INR levels.

These insights are transformative for high-risk medications, enabling more precise prescribing and improved safety.

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3. Reducing Polypharmacy and ADRs with PGx Insights

Polypharmacy is a significant challenge in geriatric care, with many older adults taking multiple medications. PGx testing can simplify medication regimens by identifying drugs likely to be ineffective or unsafe for a particular patient. This streamlining reduces polypharmacy and minimizes the risk of ADRs.

For example, a patient with a CYP2D6 variant may experience severe side effects from standard doses of certain antidepressants or opioids. By understanding this genetic predisposition, clinicians can prevent potential harm and reduce re-hospitalizations.

Key takeaway: PGx is an invaluable tool for cutting down on unnecessary medications and implementing a safer, more targeted approach to medication management in geriatrics.

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4. Interpreting and Applying PGx Test Results

Implementing PGx in clinical practice involves collaboration and careful interpretation of results. Here’s a quick guide to get started:

• Identify Ideal Candidates: Patients with a history of ADRs, poor responses to standard doses, or complex medication regimens are good candidates for PGx testing.
• Use Results for Tailored Dosing and Drug Selection: PGx categorizes patients as poor, intermediate, extensive, or ultra-rapid metabolizers, which guides both dosing and drug selection. For some, alternative medications may be more effective.
• Collaborate with Pharmacists and Specialists: PGx often requires multidisciplinary input. Pharmacists trained in PGx can help interpret results and recommend optimal dosing strategies.

Key takeaway: Successful integration of PGx in geriatric care requires a solid understanding of test selection, interpretation, and collaboration with a broader healthcare team.

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5. The Future of PGx in Geriatrics

Pharmacogenomics is still evolving, but the benefits for older adults are becoming undeniable. By tailoring medications to the individual, PGx not only improves safety but also addresses the unique needs of geriatric patients. As PGx testing becomes more accessible, it offers a level of personalization previously unattainable in traditional approaches to geriatric medicine.

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6. Navigating the Costs and Reimbursement of PGx Testing

The cost of PGx testing can vary widely, from around $150 to over $500, depending on the number of genes tested. Understanding the cost and reimbursement landscape is essential to make PGx more accessible.

• Reimbursement Landscape: Some insurance providers, including Medicare, recognize the value of PGx testing in high-risk populations. Coverage is more likely for drugs with known risks of ADRs or poor outcomes if metabolized ineffectively, especially for patients with complex conditions or poor responses to traditional therapies.
• Tips for Reimbursement: Document Medical Necessity: Document reasons such as prior ADRs, complex regimens, or poor drug response to increase coverage chances. Use Appropriate Diagnosis Codes: ICD-10 codes related to drug metabolism or ADRs can support reimbursement requests. Collaborate with a Clinical Pharmacist: Pharmacists can assist in providing documentation or evidence to support the need for testing.

Key takeaway: Although cost is a barrier, strategic documentation and coding make PGx more accessible for eligible patients, especially in geriatric populations who stand to benefit most.

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Common CPT Codes for PGx Testing

For clinicians billing PGx tests, here are some commonly used CPT codes:

• 81225 – CYP2C19 gene analysis (clopidogrel, SSRIs)
• 81226 – CYP2D6 gene analysis (antidepressants, antipsychotics, opioids)
• 81355 – SLCO1B1 gene analysis (statins)
• 81240 – VKORC1 gene analysis (warfarin sensitivity)
• 0031U – Comprehensive multi-gene PGx panel for drug metabolism

Final Thoughts

Pharmacogenomics is a game-changer for geriatric care. With PGx insights, we can improve medication efficacy, reduce ADRs, and provide a safer, more personalized approach to treatment. As PGx testing becomes more available and affordable, now is the time to adopt this approach and elevate the standard of care for older adults.

If you’re interested in integrating PGx into your practice, resources like the Clinical Pharmacogenetics Implementation Consortium (CPIC) and PharmGKB offer valuable guidelines and data.

Let’s move together and toward a future where every patient receives the most appropriate, personalized care!

Dr. Adrijana Kekic

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