Published in the June 2015 issue of Today’s Hospitalist
YOU KNOW THAT ELDERLY PATIENTS are at risk when they spend time in the hospital. But how well do you understand the role played by the drugs you give them?
At this spring’s annual Society of Hospital Medicine meeting, Melissa L.P. Mattison, MD, a geriatrician and associate chief of hospital medicine at Boston’s Beth Israel Deaconess Medical Center, said that new medications in older patients can accelerate functional decline and lead to unexpected consequences.
“What happens is a phenomenon that geriatricians call homeostenosis, which is a failure of multiple organ systems that seem unrelated to the initial insult,” Dr. Mattison explained. “As we age, we all start to use our physiologic reserve just to live every day. When an acute illness happens to older persons who are using most of their reserve just to live each and every day, there might not be any more reserve to tap into.” Sometimes, she added, even adding a new medication that taxes renal function can launch a patient into crisis.
Consider this real-world example she gave during her presentation: An 89-year-old woman comes to the ED from her assisted living facility after a fall. She is admitted to the hospital because she’s confused and frail, and it’s felt that she’s not safe to return home. In short order, she develops aspiration pneumonia and acute diastolic heart failure, becomes over-diuresed, and suffers acute kidney injury.
That’s quite a downturn, considering her baseline medical problems: hypertension, mild incontinence, osteoporosis, depression and mild dementia. Eleven days later, she is discharged to a nursing home.
What happened? A cascade of events, said Dr. Mattison, that a hospitalist might have mitigated but not averted altogether. The patient’s primary care physician had recently prescribed 50 milligrams a day of quetiapine for nighttime agitation, a detail that never made it into the electronic medical record.
“You have an 89-year-old women prescribed a fairly hefty dose of an antipsychotic that’s largely protein-bound and that the FDA black-box warning clearly says is not to be used to treat dementia,” Dr. Mattison said. “And that’s an old alert.” Quetiapine is associated with a slew of risks in the frail elderly, from dizziness and lightheadedness “enough to prompt a fall “to aspiration and “increased risk of death.”
The patient’s poor outcome was hardly an outlier. Dr. Mattison cited CDC data indicating that adverse drug events are associated with 10% of admissions, and that 30% of elderly inpatients are discharged with more disability than they had at arrival.
Common offending drugs
The moral of the story, said Dr. Mattison, is that adding new medications or even managing existing ones is a balancing act in elderly patients. That’s because these patients are likely to be orthostatic and prone to dehydration, and their blood vessels are less responsive to stress than younger patients’. Their organ systems are also more vulnerable to side effects, particularly central nervous system effects.
And because elderly patients are routinely excluded from trials, the optimal therapeutic plasma concentrations for even common drugs have not been established in this population.
“Eighty-nine-year-olds with dementia in assisted living are not high on the list of participants in drug trials.” Dr. Mattison also pointed out 40% of elderly patients take between five and nine medications, while 18% take 10 or more.
What’s a hospitalist to do? Besides digging deep to obtain an accurate medication reconciliation, you need to watch for any lipophilic drug that “likes to hang out in fat” and will have both increased distribution volume and a longer half-life. Diazepam is a classic example.
“The half-life of diazepam in a young, healthy person is estimated to be several days,” said Dr. Mattison. “I’d hate to guess what it is in an 89-year-old with a higher percentage of fat content.”
Hospitalists should also pay close attention to any protein-bound drug that will have a higher free drug plasma concentration in elderly patients than in younger ones.
Benzodiazepines are well-known offenders in terms of not only inappropriate prescribing in the elderly but being implicated in high numbers of adverse drug events. The same is true, Dr. Mattison noted, for more common drugs such as digoxin, warfarin and insulin. A study in the Dec. 4, 2007, issue of Annals of Internal Medicine found that one of those three was involved in more than one-third of ED visits made by older adults for adverse drug events.
Halving the dose
Hospitalists won’t remember the details of every medication that’s lipophilic or renally eliminated, or what the liver has to do metabolically to process a medication. Doctors can, however, start with a cautious approach.
“My rule of thumb is that drug doses usually prescribed for younger adults may be too high for older individuals,” Dr. Mattison pointed out. “It’s hard to imagine that the dose a 150-pound, 55-year-old man would require is the same for a 100-pound, 89-year-old woman.”
And while decreased hepatic metabolism may be a fact of life for the elderly, she said, “Its explanation remains elusive. We just know that there can be increased bioavailability of some drugs because of this altered pattern of metabolism.”
Experts recommend starting with half the recommended dose of most medications in elderly patients that you’d use in young or middle-aged ones. “Titrate the dose to a clearly defined therapeutic response,” Dr. Mattison added. “Monitor the patient after you start the drug to see if it’s having the intended effect.”
Intervention delivers improvements
Dr. Mattison also described the GRACE (Global Risk Assessment and Care Plan for Elders) program developed at BIDMC to alleviate some of the disability and decreased function of hospitalizing elderly patients.
In part, the GRACE bundle relies on EHR-embedded decision-support to deter physicians from prescribing drugs like antipsychotics and diazepam for patients age 80 and older. That decision-support also encourages providers to order lower doses of higher-risk but often necessary medications like narcotic analgesics. For example, the morphine default is now 2 mgs or less IV and 0.5 mgs or less for haloperidol. The initiative has been expanded to include patients age 65 and older.
A subsequent study published in the May 2014 issue of the Journal of the American Geriatrics Society found no effect of the intervention on mortality, length of stay, readmission rates or ICU stay. However, the researchers did find one telling improvement: More of the elderly patients in the GRACE cohort were discharged home “than would be predicted in this population,” Dr. Mattison said.
“Because older patients have less physiologic reserve to withstand stressors, they’re essentially standing at the edge of the cliff when we admit them,” she said. “Our job is to ensure that each medication has an indication and to avoid the prescription cascade. Question the need for each drug an elderly patient is taking, and be extremely cautious about adding any new ones.”
Bonnie Darves is a freelance health care writer based in Seattle.