LEP was not independently associated with 60- or 90-day opioid refill requests after knee arthroplasty

Description #

After multivariable adjustment, the unadjusted LEP–EP differences in opioid refill requests at 60 and 90 days did not persist: LEP status was not independently associated with a significant difference in refill requests within the first 60 or 90 days after discharge. Only the 0–30-day window remained significant in the adjusted models — a null result at the later windows.

"LEP was not independently associated with significant differences in opioid prescription refill requests within the first 60 days and first 90 days after discharge in multivariate models after adjusting for age, gender, BMI, ASA rating, median household income, insurance type, hospitalization length, prior opioid use, 1-h postoperative pain level, and discharge disposition." (Nguyen et al., 2022, p. 3)

Methods Context #

What? #ⓘ

The observable: opioid pain-medication refill requests recorded in the EHR within 0–60 and 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? #ⓘ

Multivariable logistic regression models for the 60- and 90-day windows, adjusting for the same a priori covariate set used in the 30-day model.

"Multivariable logistic regression modeling was performed to calculate the odds ratio of opioid refill requests 0–30 days after discharge." (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 null tempers the primary finding: the independent LEP effect on refill requests was demonstrated only for the earliest (0–30-day) post-discharge window.

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.
• Single-center single-service retrospective cohort with race excluded for collinearity (Nguyen TKA opioid study) The findings come from a retrospective observational cohort at a single academic medical center, all discharged from the same surgical service — which limits generalizability and cannot establish causation for the LEP–refill association. The study collected no qualitative data from patients or providers to elucidate the mechanisms behind the disparity. Additionally, race/ethnicity was excluded from the multivariable model because of high collinearity with LEP status [Inferred: this means the independent effects of language versus race/ethnicity cannot be disentangled in the adjusted analysis], so residual confounding by the closely related dimensions of race, ethnicity, and socioeconomic status cannot be ruled out.