WASHINGTON — Older patients with pain resulting from diabetic peripheral neuropathy are more likely to be treated with fewer categories of pain medications than are younger patients, according to a poster presented at the annual meeting of the American Pain Society.
Roughly half (51%) of patients aged 65 years or older with diabetic peripheral neuropathy (DPN) were prescribed only one category of drugs on average to treat their pain each year, compared with 40% of those younger than age 65 years, wrote Stephen Able, Ph.D., a researcher at Eli Lilly & Co., and his colleagues. Lilly makes Cymbalta (duloxetine), which has Food and Drug Administration approval for the treatment of pain associated with DPN.
The researchers used pharmacy data from the Department of Veterans Affairs' National Pharmacy Benefits Management Program as well as VA administrative data, including inpatient and outpatient files from Oct. 1, 2001, through Sept. 20, 2004. Patients were included if they had a diagnosis of diabetes (based on ICD codes) or a pharmacy claim for a diabetic medication. Patients also had to have a diagnosis of neuropathy and an outpatient prescription drug claim for medication recommended for the management of pain.
Patients were excluded if they had a diagnosis of schizophrenia, bipolar disorder, psychosis, depression, or anxiety.
In particular, the researchers looked at the numbers of different pain-related medication categories used to treat patients with DPN annually and the percentage of patients with DPN using medications from each category. Categories included anticonvulsants, antidepressants, short- and long-acting narcotics, and nonnarcotic analgesics.
In fiscal years 2002, 2003, and 2004, the analysis included 52,947 patients, 54,924 patients, and 58,145 patients, respectively.
Patients 65 years of age and older were less likely to receive a prescription for more than one category of medications. On average, 30% of those 65 years of age and older had prescriptions for two categories of pain medication each year, compared with 32% of those younger than 65 years. Additionally, 13% of those aged 65 and older had prescriptions for three categories of medication, compared with 19% of those younger than 65.
The researchers hypothesized that the differences in prescribing patterns between the age cohorts may reflect different strategies for managing pain in older patients with DPN as a result of greater concerns about drug tolerability in this age group; differences in the manifestations of pain associated with DPN as the condition progresses; and/or changes in patient perception of pain as they age.
Overall, nonnarcotic analgesics (COX-2 inhibitors, NSAIDs, and others) were the most commonly prescribed category of pain-related medications in this population—70% or more in each of the study years.
However, the use of long-acting narcotics (tramadol, oxycodone, and others) doubled during the study period, up from 7% overall in fiscal year 2002 to 14% overall in fiscal year 2004. The use of anticonvulsants (gabapentin and others) increased steadily in both age groups with time, although more so for the younger cohort.
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