Prescribing changes as patients near death
A study intended to determine how prescribing for comorbid illnesses and symptom control changes during the palliative phase of a terminal illness found older people take more medications and says medications for comorbid conditions should be reviewed in the context of their original therapeutic goals.
Published in the Journal of the American Geriatric Society, the Australian study reported that chronic comorbid conditions are commonly encountered in people with life-limiting illnesses, with the most frequently seen being cardiovascular diseases, including hypertension; chronic obstructive pulmonary disease; and diabetes. "Management of these comorbid problems needs to be actively reviewed in response to the systemic changes encountered in the palliative phase of a life-limiting illness," the researchers wrote.
The study was conducted in Adelaide, South Australia, where specialized palliative care services funded by the state government provide consultative specialist nursing, medical, and allied health support for general practitioners and community nurses who are the primary point of care. Palliative care services there are organized as regional whole population networks.
Lead researcher David Currow, BMed, MPH, says that because one study aim was to improve specialized palliative care delivery, eligibility criteria were broad. All adult patients referred to the service with any form of pain in the preceding three months were eligible after providing written informed consent. Patients who were expected to die within 48 hours or who lived outside the geographic region served by the team were excluded.
As part of the study, enrolled patients underwent community-based nursing reviews at baseline, biweekly for three months, and then at least monthly until death. Data collected included a list of medications taken regularly at each specialist nursing review. Medication reports included generic drug name, dose, route of administration, indication and frequency, and pattern of use (regularly or as needed). Medications were divided into two categories: those for comorbid conditions and those for symptom control for the patients' life-limiting illnesses. Areas of overlap such as antidepressants or anti-epileptic medications (both of which are also frequently used for neuropathic pain) were classed with symptom-control medications.
According to Currow, many of the study findings appear intuitively logical but have not been documented previously. It is clear, he says, that as health care practitioners recognize the palliative phase of life-limiting illnesses, comorbid conditions must be actively managed.
Generally, new medications were added to patients' regimens for symptom control as the primary life-limiting illness progressed. Although there was a statistically significant decrease in medications for comorbid medical conditions, this reduction occurred at the time at which an increase in symptom control medication was noted. That overlap coincides with a period of decreasing function, the researchers said, and future research is needed to define whether the overlap is contributing to an acceleration in declining global function.
Medications for comorbid conditions, especially for secondary prevention, may be continued for longer than clinically indicated, Currow says, with a consequent potential risk of iatrogenic harm. He says there may be opportunities to prevent morbidity and even premature mortality in a person with a life-limiting illness, especially in older people, if medications for comorbid conditions are more actively managed. Likewise, judicious use of symptom-control medications is needed because there is the risk from many of these medications for adverse reactions and adverse medicine interactions for which other strategies may lessen potential harm.
Although the study found that clinicians reduced the number of medications for comorbid conditions, there were an increasing number of medications for symptom control introduced that met high-risk criteria. Given the frailty of the population receiving palliative care, the researchers said, and the predictable decline in functional status, minimizing medications that meet the consensus-derived Beers' risk criteria is important.
The study found that adverse drug reactions and interactions increase when more medications are taken. "The risk of an adverse medication interaction is greater than 80% when more than seven medications are taken regularly," Currow asserts. "Significant drug-drug interactions have been documented in a population receiving palliative care. In the setting of a life-limiting illness, pathophysiological changes such as cachexia can lead to changes in metabolism, excretion, and volume of distribution of long-term medications that need to be considered when assessing their ongoing net benefit. The underlying indications for the management of long-term conditions such as hypertension or diabetes may also change with cachexia-associated weight loss at the end of life."
Don't stop meds completely
The researchers caution they are not suggesting that medications for comorbid conditions should be stopped simply because a person has a life-limiting illness, noting that many medications for comorbid conditions need to be continued judiciously to maintain optimal function and comfort for the patient.
Now that their study established a baseline, the researchers say, other hospital units need to collect similar longitudinal data to compare with these findings. Also, specific work needs to be performed to adapt the Beers' criteria to the palliative care population. And guidelines and frameworks suggested in the literature for managing comorbid illnesses for people with a life-limiting illness need to be prospectively evaluated to define the magnitude of reduction in any adverse outcomes in that population with continually changing physiology.