Suboptimal adherence to food restrictions requirements related to drug regimens for chronic diseases

Abstract

Background

Oral medications for chronic conditions often involve a variety of instructions, including time of day/dosing, drug interactions, and food intake restrictions. However, the extent to which patients follow these instructions is unclear.

Methods

We surveyed patients from the US and Europe (UK, France, Germany, Italy, Spain) who were prescribed sulfonylureas (SU: glimepiride, glipizide, or gliclazide) for diabetes or levothyroxine for hypothyroidism. Patients kept a daily diary for 3–5 days documenting their adherence to three criteria: dosing regimen including time of day, warning labels including drug interactions, and food restrictions.

Results

A total of 421 US and 493 European patients took the study medications; 546 patients took SU and 368 took levothyroxine. Overall, 48% of patients were males; 46% were age 65 years or older. Despite most patients having received instructions on medication requirements (US 71%, EU 75%), most patients reported being only somewhat knowledgeable (US 69%; EU 71%). Adherence, measured by the proportion of the days a participant was adherent to each category out of the observational period (ranging from 3–5 days), varied by type of instruction, with the poorest adherence observed for food restriction requirements (US 34% of the observation days, EU 26%) compared to warning labels (US 77%, EU 67%) and dosing regimen (US 85%, EU 87%).

Conclusions

Patients adhered to dosing and cautionary instructions across the majority of the study period but were largely non-adherent to food intake restrictions. Improved communication and increased emphasis on food intake restrictions is needed when advising patients on their medications.

Keywords:

• Adherence
• compliance
• medication education
• dosing instructions
• product label

Transparency

Declaration of funding

Financial support for research conduct and manuscript preparation was provided by Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA.

Declaration of financial/other relationships

RLB, SE, T Weiss, SR, and DL are employees of Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA (MSD) and stockholders of Merck & Co., Inc., Rahway, NJ, USA. T Wang was an employee of MSD at time of study conduct. AAM, NW, BR, and LY are employees of Cerner Enviza, which received payment from MSD to conduct the research. Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Author contributions

SR, DL, SE, T Weiss, and T Wang were responsible for study conception, with all authors contributing to study design. BR and NW executed the study. LY analyzed the data. AAM and RLB drafted the manuscript. All authors have read and approved of the final manuscript and agree be accountable for all aspects of the work.

Acknowledgements

None.

Data availability statement 

The data that support the findings of this study were used under license by Cerner Enviza, and so are not publicly available. However, data can be made available for non-commercial use from the authors upon reasonable request and with the explicit written permission of Cerner Enviza.

Ethics statement

This research was conducted in accordance with the Declaration of Helsinki and the Good Pharmacoepidemiology Practices (GPP) guidelines issued by the International Society for Pharmacoepidemiology (ISPE). This study was reviewed and granted exemption by the Pearl Institutional Review Board (Indianapolis, IN). All participants provided their consent prior to participating in the study.