Rates of Repeated Overdose Linked to Opioid Prescribing After Non-Fatal Overdoses

Deaths due to prescription opioids quadrupled between 1999 and 2010, but little is known about prescribing patterns surrounding an overdose. Researchers examined insurance claims and found 91% of patients were dispensed opioids after a nonfatal overdose. Several factors were identified as risk indicators for a repeat overdose; however, buprenorphine dispensing was not associated with increased risk for repeat overdose.

 WHAT PROBLEM DOES THIS STUDY ADDRESS?

Until recently, prescribing opioids for non cancer-related chronic pain had increased dramatically. In parallel, opioid misuse and rates of overdose have increased in recent decades. Presentation to an emergency department (ED) or hospital with a nonfatal overdose is an opportunity to identify and refer patients who may be misusing opioids, however, patterns of treatment, including rates of continued prescribing are unknown.

This study aims to describe prescribing patterns following a nonfatal overdose, and determine its relationship to a second overdose. Ultimately, this study may help to prevent overdoses if we better understand more about how prescribing patterns may be related to overdose risk.

HOW WAS THIS STUDY CONDUCTED?

This study analyzed insurance records from a U.S. health insurer during the years 2000-2012. Starting with a pool of 50 million commercially insured patients, Larochelle and colleagues identified a cohort of 2,848 adults who had a nonfatal opioid overdose during long-term opioid therapy. In order to determine the daily opioid dosage surrounding the time of overdose, patient’s records were examined 90 days before and up to 2 years after the overdose. Daily opioid dosage was divided into: none, low (< 50 mg of morphine-equivalent dispensing [MED]), moderate (50 to < 100 mg MED), and high (≥100 mg MED).

Secondary outcomes that were examined after the overdose included:

1. risk for a subsequent overdose
2. how many patients switched providers.

Additionally, in order to better describe the sample, they determined how many patients had insurance claims with a diagnosis of substance use disorder, mental health disorder, or dispensing of a benzodiazepine.

WHAT DID THIS STUDY FIND?

60 days before the overdose, the mean daily dosage ranged between 152 mg (e.g., moderate dose) and 164 mg (e.g., high dose) of morphine-equivalent dispensing (MED) until the week before the overdose, mean dosage increased, peaking 187 mg MED on the day before the overdose.

30 days after the overdose, the mean dosage had decreased to 118 mg MED (e.g., high dose) and remained relatively stable for the 2 year follow-up.

A repeat overdose occurred with 7% (n = 212) of patients by the two-year follow-up, however, 72% of the sample was censored (e.g., missing) at the two year follow-up due to health plan disenrollment or becoming 65 years of age (Medicaid eligible).

Several factors were associated with risk for a repeat overdose including:

1. higher levels of dosage (≥ 100 mg morphine-equivalent dispensing (MED))
2. active dispensing of benzodiazepine (which occurred for 58% of patients).

Many patients switched providers after the overdose. From the subset of 1,964 patients for whom the researchers were able to identify the primary prescriber before and after the overdose, 30% switched to new prescriber.

Active dispensing of buprenorphine (7% of patients) was not associated with a higher risk of repeat overdose.

WHY IS THIS STUDY IMPORTANT

Opioid prescribing is common after a nonfatal overdose (91% of patients received opioid dispensing). Furthermore, a considerable number of patients (between 31% and 36%) may receive high doses (≥100 mg morphine-equivalent dispensing (MED)) within 30 days following an overdose.

Patients who receive high (e.g., large) doses are at the greatest risk for repeat overdose.

Patients who have a low dose (< 50 mg of MED) are at no greater risk of repeat overdose than patients who have no prescription. Importantly, buprenorphine dispensing was not associated with increased risk for a repeat overdose.

LIMITATIONS

1. This study is limited to use of opioids as defined by insurance claims (e.g., using insurance to pay for an opioid prescription). The extent of misclassification of opioid dosage because of patients who paid cash as opposed to using insurance is unknown.
2. Additionally, this study is limited to overdose treatment in the emergency department or inpatients settings. Overdoses that were treated in out-of-hospital settings are not reflected in this report (e.g., walk-in clinics).
3. Last, this analysis included commercially insured patients which limits generalizability to patients in other settings, such as the Medicaid and Veterans Affairs systems, where risk of overdose is known to be higher (Center for Disease Control, 2009).

NEXT STEPS

Future research should disentangle how many of patients who receive a high dose of morphine-equivalent dispensing (MED) (≥100 mg) also have a substance use disorder. This study showed that patients with high daily opioid doses are at the greatest risk for a repeated overdose, it is not reported how many of the high daily opioid patients were diagnosed with a substance use disorder. This subgroup analysis may have been outside the scope of the original paper.

Additionally, research is needed to determine whether providers continuing to prescribe opioids after an overdose are aware of the event and, if so, how they respond in counseling patients.

BOTTOM LINE

CITATIONS

Larochelle, M. R., Liebschutz, J. M., Zhang, F., Rosss-Degnan, D. (2015). Opioid prescribing after nonfatal overdose and association with repeated overdose. A cohort study. Annals of Internal Medicine, 164, 1-9.