LEP patients requested fewer opioid refills than EP within 90 days (54.0% vs 62.9%) after knee arthroplasty

Description #

In unadjusted bivariate analysis, LEP patients were less likely than EP patients to request an opioid prescription refill within the first 90 days after discharge for total knee arthroplasty (54.0% vs 62.9%, p = 0.041) (Fig. 1). The difference persisted out to 3 months, though it was the smallest and least significant of the three windows — an attenuating gradient from 30 to 90 days.

"LEP patients were less likely to request an opioid prescription refill within 30 days (35.3% vs 52.4%, p < 0.001), 60 days (48.7% vs 61.0%, p = 0.004), and 90 days (54.0% vs 62.9%, p = 0.041) after discharge." (Nguyen et al., 2022, p. 1)

Methods Context #

What? #ⓘ

The observable: opioid pain-medication refill requests recorded in the EHR within 0–90 days of discharge.

"Primary outcome variables included opioid pain medication refill requests between 0 and 30 days, 0–60 days, and 0–90 days from discharge after TKA." (Nguyen et al., 2022, p. 2)

How? #ⓘ

Bivariate comparison of refill-request proportions between EP and LEP patients using Fisher's exact test, within a retrospective EHR cohort study.

"Bivariate analyses comparing EP and LEP patient characteristics were performed using a t-test for continuous variables and Fisher's exact test for categorical variables." (Nguyen et al., 2022, p. 2)

Who? #ⓘ

2148 adults (≥18 years) who underwent TKA at a single academic medical center between 2015 and 2019; 9.8% (211) were classified as LEP.

"A total of 2148 patients underwent TKA between January 2015 and December 2019. Overall, 9.8% (211) of these patients were classified as having LEP." (Nguyen et al., 2022, p. 2)

Other Notes #

This unadjusted 90-day difference did not remain significant after multivariable adjustment (see companion EVD on the adjusted 60- and 90-day null).

Caveats #

• Opioid refill requests (not pharmacy dispensing or OME) are an indirect proxy for postoperative medication access The outcome is a refill request recorded in the EHR, not pharmacy dispensing data or oral morphine equivalence (OME) actually received. Dispensing data would be a more direct measure of whether patients obtained refills, and OME would give a more granular measure of postoperative opioid usage. The authors infer that fewer refill requests likely correlate with fewer pickups, but the study cannot confirm actual medication access or consumption — so the observed disparity may over- or under-state the true difference in postoperative opioid access between LEP and EP patients.