San Francisco—Latino patients, even those who speak English, are much less likely to adhere to newly prescribed diabetes drug regimens than white patients, according to a new study.

The report in JAMA Internal Medicine discusses how patient race/ethnicity, preferred language, and physician language concordance affects how well medication instructions are followed.

The observational study, led by researchers from the University of California–San Francisco and San Francisco General Hospital, was conducted from January 1, 2006, to December 31, 2012, at a large integrated healthcare delivery system with professional interpreter services, Kaiser Permanente Northern California healthcare system.

Included in the analysis were insured patients with type 2 diabetes, including 21,878 English-speaking white, 5,755 English-speaking Latino, and 3,205 limited English proficiency (LEP) Latino patients with a total of 46,131 prescriptions for diabetes medication. Among LEP Latino patients, 50.2% had a primary care physician reporting high Spanish fluency.

The study team sought to determine in what circumstances the following occurred:
• Primary nonadherence (never dispensed),
• Early-stage nonpersistence (dispensed only once),
• Late-stage nonpersistence (received two more dispensings, but discontinued within 24 months), and
• Inadequate overall medication adherence (more than 20% time without sufficient medication supply during 24 months after initial prescription).

Results indicate that early adherence varied substantially for oral medications, with 32.2% of LEP Latino patients, 27.2% of English-speaking Latino patients and 18.3% of white patients either primary nonadherent or early nonpersistent. Inadequate overall adherence was observed in 60.2% of Latino patients, 37.5% of English-speaking Latino patients, and 37.5% of white patients.

As for use of insulin, early-stage nonpersistence was 42.8% among LEP Latino patients, 34.4% among English-speaking Latino patients, and 28.5% among white patients.

After adjustment for patient and physician characteristics, LEP Latino patients were more likely to be nonadherent to oral medications and insulin than English-speaking Latino patients, for relative risks of 1.11 to 1.17, or white patients, relative risks from 1.36 to 1.49. English-speaking Latino patients were more likely to be nonadherent compared with white patients, relative risks from 1.23 to 1.30. Interestingly, patient-physician language concordance was not associated with rates of nonadherence among LEP Latinos, with relative risks from 0.92 to 1.04.

“Nonadherence to newly prescribed diabetes medications is substantially greater among Latino than white patients, even among English-speaking Latino patients,” study authors write. “Limited English proficiency
Latino patients are more likely to be nonadherent than English-speaking Latino patients, independent of the Spanish-language fluency of their physicians. Interventions beyond access to interpreters or patient-physician language concordance will be required to improve medication adherence among Latino patients with diabetes.”

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