Background: Hospital inpatients frequently require opioid analgesics for pain management, with more than half of US patients in acute-care facilities receiving opioids during their stay. With the rise of opioid drug therapy, the need to identify inpatient prescription patterns has become urgent, given that mortality rates attributed to prescription opioids have more than tripled since 2000. This study aims to determine the prevalence of each type of opioid used on internal medicine admissions in the inpatient setting, and to discern patterns of inpatient opioid use.

Methods: Data were pulled from the medical center’s centralized data repository that integrates clinical and biomedical information. Adult patients (18 years or older) who were prescribed and administered any opioid analgesic therapy during their inpatient stay between January 2015 and December 2017 were included in the analyses. Dosages of opioids administered were obtained and subsequently standardized by converting to the oral morphine equivalent (OME). Mean cumulative daily dose of opioids was calculated for each admission. A bivariate analysis was conducted to identify variables that have a significant association with opioid analgesic therapy for inclusion in a subsequent multivariable analysis. Stepwise regression was then conducted to identify a best-fitting model, using Bayesian Information Criterion and forward-backward selection method.

Results: The sample included 614 patients comprising 716 internal medicine admissions. Patient age was 56 ± 18 years with 57% female. Mean length of stay was 3.5 days. The most frequently administered opioids were oxycodone and fentanyl. Notably, 13% of inpatients received 2 doses of intravenous opioid medications in the last 24 hours of the inpatient stay. When plotting opioid usage patterns across all patients studied, it was noted that the mean opioid dose for each patient remained relatively consistent regardless of length of admission; however, frequency of opioid administrations decreased throughout the patient stay. Variables associated with opioid therapy were history of diabetes (DM), history of diabetes complications (DMcx), history of drug abuse (Drugs), history of psychoses, and length of stay (LOS). DM has a negative, significant effect on opioid daily use. DMcx has a negative, marginally significant effect on opioid daily use. Drugs, history of psychoses, and LOS have a positive, significant effect on opioid daily use. These five predictor variables explained 14% of the variance of opioid daily use.

Conclusions: This study provides insight into opioid prescribing patterns for inpatients and the need to set appropriate protocols for pain relief practices. Nearly 1 in 8 patients received IV opioid medications within 24 hours of discharge. Additionally, fentanyl and oxycodone were the primary choices for inpatient pain treatment. Because of their potency and potential for addiction, adjunct and alternative pain management therapies need to be explored. This study also suggests high utilizers of opioid therapy can be characterized as those who have longer periods of inpatient stays and a history of diabetes, psychoses, or drug abuse. However, a substantial degree of unexplained variance in the best fit model suggests that other factors are in play. Nevertheless, these findings can inform efforts to improve the safety and efficacy of inpatient opioid prescribing.