Maximum days of medication non-adherence were lower for Nepali- and Spanish-speakers than English-preference patients

Description #

Maximum Days of Non-Adherence (the longest gap a patient went without their medication on hand) was significantly lower for Nepali- and Spanish-speakers than English-preference patients for NPH insulin, and for Nepali speakers also for metformin and ACE inhibitors — i.e., the English-preference group had the longest non-adherence gaps (Table 2).

"Maximum Days of Non-Adherence was significantly less for Nepali- and Spanish-speakers compared to English-preference speakers for NPH insulin. This was true for metformin and ACE-inhibitors for Nepalis compared to English preference speakers, but not for Spanish-speakers." (Kahler, 2022, p. 33)

Methods Context #

What? #ⓘ

The observable: Maximum Days Non-Adherent = (total days prescribed medication) − (days supply of medication), per medication, from pharmacy refill gaps.

"Maximum Days Nonadherence = # of total days prescribed medication − # of days supply of medication" (Kahler, 2022, p. 32)

How? #ⓘ

Computed from pharmacy refill-gap data and compared across the three language groups via ANOVA / regression with adjustment for confounders (age, sex).

"Maximum Number of Days Non-Adherent was calculated for each medication based on gaps in medication refill data collected from pharmacy medication profiles." (Kahler, 2022, p. 32)

Who? #ⓘ

The same 59 type 2 diabetes primary-care patients; medication-specific subsamples (e.g., NPH insulin n=25, metformin n=32, ACE inhibitors n=21).

"Models included data for all participants taking each type of medication." (Kahler, 2022, p. 32)

Other Notes #

Maximum Days Non-Compliant showed significant heteroskedasticity (Breusch-Pagan/Cook-Weisberg), so the authors flagged this outcome as possibly not valid for comparing language groups (see caveat).

Caveats #

• Pharmacy-refill Adherence Ratio does not capture whether medication was actually taken correctly Adherence was measured indirectly from pharmacy refill data (the Adherence Ratio), a surrogate chosen because no validated direct metric was available. This captures whether medication was obtained, not whether it was actually taken correctly — a construct-validity gap. The authors also note patients may have filled prescriptions at unlisted pharmacies, undercounting fills.