2012 National Meeting

1080 — The Association of Length of Opioid Therapy and Days Since Last Opioid Fill with Opioid Overdose Death

Bohnert ASPfeiffer PNGanoczy DIlgen MAValenstein MEisenberg A, and Blow FC, COE- Ann Arbor;

Total daily prescribed opioid dose is associated with risk of unintentional opioid overdose among individuals receiving care in the Veterans Health Administration (VHA), but the effect of other aspects of prescribing on overdose risk is unknown. The present study examined the association of length of opioid therapy and days since last opioid fill with opioid overdose mortality among VHA patients with chronic pain.

This was a nested case control study, with risk-set sampling of controls, and a 4 to 1 ratio of controls to cases. Cases were those individuals who died by unintentional or unknown intent overdoses due to codeine, morphine, oxycodone, hydrocodone, oxymorphone, and/or hydromorphone between FY2004 and FY2008 (determined by National Death Index records), and were prescribed one of the same opioids used in the overdose at the time of death (determined by outpatient pharmacy records), and who had a chronic pain diagnosis (n = 363). Individuals eligible to be selected as controls for each case were those prescribed one of the same opioids on the date of the case’s death, had a chronic pain diagnosis, were the same gender and were within ±5 years of age of the case. We used conditional logistic regression to test the association of length of opioid treatment and days since last fill with case status.

Adjusting for age and total prescribed dose, number of days since last opioid fill was significantly associated with opioid overdose death (OR = 0.984 per day since fill, 95% CI:0.971, 0.998). Length of opioid therapy was only associated with overdose death in unadjusted models (7-29 days of treatment compared to 365+ days: OR = 0.52, 95% CI: 0.27, 0.99).

The days immediately after an opioid fill likely represent a high-risk period for unintentional opioid overdose mortality.

Although opioid medications are an important tool in pain treatment, new policies and clinical procedures are needed to optimize the benefits and reduce the risks associated with opioids. Potentially, patients identified as being at elevated risk for overdose should be given fewer days supplied at once to reduce the total amount of opioids on hand at any given time.