Opioid Analgesic Use among Dialysis Patients Is Increasing

A recent study suggests that dialysis patients' use of opioid analgesics (OAs) is widespread and exceeding historical limits, and that the patients who use opioids are staying on them longer. Hydrocodone and oxycodone, each in combination with acetaminophen, are the most widely prescribed opioid analgesics, and studies to investigate their relative safety and potential for overuse in dialysis patients are needed.

Eric D. Weinhandl, MS, epidemiologist for the United States Renal Data System Coordinating Center in Minneapolis, and colleagues reported their findings at Kidney Week 2013, the American Society of Nephrology's annual meeting in Atlanta, GA, on November 9, 2013.

According to the study authors, pain is common among dialysis patients due to comorbid conditions, complications of renal failure, and the dialysis procedure itself, and it can be debilitating. Although opioid analgesics are often prescribed in the United States, few data exist regarding their use among dialysis patients. A review of 10 studies of dialysis patients from 1996 to 2006 showed that 5-36% of these patients use OAs. For the current study, the authors used Medicare Part D data to describe the use of opioid analgesics (OAs) among adult dialysis patients between 2007 and 2011.

Patients analyzed in the United States Renal Data System (USRDS) database satisfied all these criteria for each year between 2007 and 2011: initiated dialysis no later than March 31 of the prior year; received dialysis and carried Medicare Parts A and B as the primary payer from June 1 to December 31 of the prior year; and carried Medicare Part D from January 1 of year being considered until their kidney transplant, death, or December 31st, whichever came first. Whether each patient was receiving the low-income subsidy (LIS) was also recorded. Medication use information was collected from Part D prescription drug fill data and exposure to OAs was classified as either 1 or more prescription fills, or 6 or more fills in the year being considered. Adjusted exposure odds ratios were estimated by logistic regression.

Between 2007 and 2011, the percentage of patients with 1 or more OA fills ranged from 60.8% to 62.2%, while the percentage of patients with 6 or more fills increased from 21.7% to 24.3%, and the cumulative OA supply among users increased from 108 to 130 days per patient-year.

In 2011, the most popular OAs were hydrocodone/acetaminophen (APAP) (42.1%), oxycodone/APAP (17.9%), tramadol (13.5%), codeine/APAP (7.1%), and oxycodone (6.1%); fentanyl, hydromorphone, morphine, and tramadol/APAP were taken by over 1% of patients; and propoxyphene had been taken off the market in 2010. Increased exposure to opioid analgesics is associated with lower socioeconomic status, and among the LIS patients, 27.1% received 6 or more fills compared with 15.0% of non-LIS patients.

The authors urged that more studies about the nature and effect of opioid analgesic treatment among dialysis patients be undertaken, including those that investigate evidence of their overuse and the safety of persistent exposure.