Identifying the Relative Importance of Factors Influencing Medication Compliance in General Patients Using Regularized Logistic Regression and LightGBM: Web-Based Survey Analysis.

Background: Medication compliance, which refers to the extent to which patients correctly adhere to prescribed regimens, is influenced by various psychological, behavioral, and demographic factors. When analyzing these factors, challenges such as multicollinearity and variable selection often arise, complicating the interpretation of results. To address the issue of multicollinearity and better analyze the importance of each factor, machine learning methods are considered to be useful.

Objective: This study aimed to identify key factors influencing medication compliance by applying regularized logistic regression and LightGBM.

Methods: A questionnaire survey was conducted among 638 adult patients in Japan who had been continuously taking medications for at least 3 months. The survey collected data on demographics, medication habits, psychological adherence factors, and compliance. Logistic regression with regularization was used to handle multicollinearity, while LightGBM was used to calculate feature importance.

Results: The regularized logistic regression model identified significant predictors, including "using the drug at approximately the same time each day" (coefficient 0.479; P=.02), "taking meals at approximately the same time each day" (coefficient 0.407; P=.02), and "I would like to have my medication reduced" (coefficient -0.410; P=.01). The top 5 variables with the highest feature importance scores in the LightGBM results were "Age" (feature importance 179.1), "Using the drug at approximately the same time each day" (feature importance 148.4), "Taking meals at approximately the same time each day" (feature importance 109.0), "I would like to have my medication reduced" (feature importance 77.48), and "I think I want to take my medicine" (feature importance 70.85). Additionally, the feature importance scores for the groups of medication adherence-related factors were 77.92 for lifestyle-related items, 52.04 for awareness of medication, 20.30 for relationships with health care professionals, and 5.05 for others.

Conclusions: The most significant factors for medication compliance were the consistency of medication and meal timing (mean of feature importance), followed by the number of medications and patient attitudes toward their treatment. This study is the first to use a machine learning model to calculate and compare the relative importance of factors affecting medication adherence. Our findings demonstrate that, in terms of relative importance, lifestyle habits are the most significant contributors to medication compliance among the general patient population. The findings suggest that regularization and machine learning methods, such as LightGBM, are useful for better understanding the numerous adherence factors affected by multicollinearity.