Clinical Value of Pharmacogenomics Is Undeniable for OAs in LTC

^{By Joel Diamond, MD, FAAFP}

Arguably no population can benefit more from the value of precision medicine – specifically, pharmacogenomics (PGx)—than the elderly or those being treated in long-term care facilities for chronic conditions and complex comorbidities.

PGx uses results from a noninvasive genetic test (cheek swab), focusing on those enzymes that enable drugs to be metabolized into active form and to ensure effective body clearance. Genetic variations may indicate a patient is a rapid or ultraslow metabolizer of specific medications, which interferes with efficacy and gives rise to significant safety concerns (eg, toxicity, side effects).

Results from simple PGx testing, however, give providers in all care settings information necessary to determine which medication is best for patients. It eliminates “trial-and-error” medication decisions, allows providers to arrive at the most effective drug as the first line of therapy, improves medication safety, reduces hospital readmissions and helps patients maintain higher overall quality of life.

Let us explore some practical examples.

A pharmacist in the Midwest shared a story about a patient in her mid-50s who had been receiving care in skilled nursing facility since she was a child because of severe developmental disabilities and abnormal behaviors. She was prescribed antipsychotics, which caused a movement disorder and high sugar levels. Another medication was added to address the movement concerns and this, in turn caused constipation—which resulted in further agitation and a subsequent increase in antipsychotic medication.

Finally, the patient’s physician ordered a PGx panel, which revealed the patient was a poor metabolizer of the antipsychotic—and the subsequent problems cascaded from there. The drug accumulated in the patient’s body and blood work showed her dose needed to be decreased by 75%, if not discontinued altogether. When these steps were taken, the patient’s side effects were resolved and her behavior and movement disorders grew much less severe.

Similarly, a colleague on the West Coast is using PGx testing with elderly, polypharmacy patients. When assessing the overall wellness of patients, this physician found that the drugs patients take played a significant role in areas such as whether they are able to exercise, are cognitively intact, engage in social interaction and are safe from falling. He has learned that about one in three patients suffering from early cognition impairment can be “pulled out” of that progression. His staff evaluates patient diagnoses like diabetes, high blood pressure or depression, as well as sensory systems like vision, hearing and balance – noting medications play a huge role in many of these. If they are not accurate, safe or therapeutically effective, treatment is likely to be unsuccessful.

It is in the best interest of long-term care leaders to work with hospital partners, pharmacy benefits managers, and referring providers to incorporate PGx into standard clinical practice.

• Consider the cost of medications for patients being treated at long-term care facilities. Most take multiple medications for multiple conditions. While drug allergies and drug-drug interactions are carefully monitored, drug-gene implications are overlooked, and yet they affect a large portion of the population. Research published in Nature a few years ago reported that 18 percent of prescriptions in the U.S. were likely impacted by PGx factors. In addition, a previous study indicated 34 percent of all potential major adverse drug reactions are caused by patient genetics rather than drug-drug interactions.
  Besides the fact that these concerns underscore that patients are not getting the anticipated therapeutic value (increasing overall costs of care through follow up visits, unnecessary testing, etc.), it also means money is being wasted on the trial-and-error process of medication selection. Use of PGx testing during clinical decision making across the continuum can help lower these costs significantly.
• Likewise consider how drug-gene interactions can impact readmission rates, an incredibly important quality measure that impacts the relationship between the hospital and long-term care facility. Patients taking drugs they metabolize poorly may have balance issues, leading to falls and inpatient care, for example. Similarly, those prescribed antibiotics through a peripherally inserted central catheter line might not tolerate the specific medication and suffer severe vomiting, dehydration and a hospital visit. PGx provides a first line of defense caregivers can use to make sure their patients’ medical issues cannot be simply corrected by selecting a medication better suited to their genetic makeup.

And, perhaps more importantly, PGx can improve the quality of care and quality of life for patients. PGx will help their providers ensure their conditions are being treated in the best way possible and that their medications are not triggering uncomfortable or deleterious side effects.

PGx and other applications of precision medicine (eg, identifying genetic risks for diseases across the clinical spectrum) are rapidly becoming the gold standard of care. Increasingly, providers—from family care physicians, to internists, cardiologists, neurologists and more—recognize that having PGx information within their native workflow to support optimal clinical decision making represents the next giant step forward for healthcare.

Joel Diamond, MD, FAAFP, is a diplomat of the American Board of Family Practice and a fellow in the American Academy of Family Physicians. He cares for patients at Handelsman Family Practice in Pittsburgh and serves as Chief Medical Officer for 2bPrecise.