Factors Affecting Rational Use of Medicine Competency of Nurse Practitioners: An Application of the Social Ecological Model

Abstract

Introduction Rational use of medicines (RUM) is a fundamental principle aimed at ensuring that patients receive medications appropriate to their health conditions, while maximizing benefits for patients, families, communities, and the health care system. Within the context of primary care units, which are responsible for managing both common illnesses and chronic non-communicable diseases on a continuous basis, RUM is particularly critical. Inappropriate medication use can lead to adverse drug events as well as unnecessary expenditures. In Thailand, nurse practitioners (NPs) serve as a cornerstone of primary care services. Therefore, competencies in RUM among NPs should not be regarded merely as individual skills. Examining the socio-ecological factors that influence these competencies will provide valuable insights for strengthening and sustaining RUM among NPs. 

Objectives This study aims to examine the factors affecting the competencies of NPs in RUM within primary care settings. The specific objectives are: (1) to describe the RUM competency of NPs, and (2) to investigate the socio-ecological factors that jointly predict the RUM competency of NPs.

Design This study employed a cross-sectional correlational descriptive design, guided by the socio-ecological framework. The framework includes multiple levels of influencing factors, including individual-level factors, interpersonal relationship factors, organizational factors, community-level factors, and policy-level factors.

Methodology The study participants comprised 272 nurse practitioners working in primary care units in Suphanburi Province. They were selected using stratified random sampling proportional to the number of practitioners in each district, followed by simple random sampling within each stratum. Inclusion criteria were: holding a professional nursing and midwifery license; completion of the four-month short-course program in primary medical care accredited by the Thailand Nursing and Midwifery Council, or a master’s degree in community nurse practitioners; full-time employment in a primary care clinic; at least one year of work experience in such settings; and willingness to participate in the study. Exclusion criteria included failure to meet the inclusion requirements or submission of incomplete questionnaires. Sample size was determined using G*Power 3.1.9.6 for multiple regression analysis, with a medium effect size, a significance level of .05, and a statistical power of .80. An additional 25% was added to account for potential incomplete data. The research instrument was a questionnaire developed by the researchers, consisting of seven parts: (1) demographic information; (2) individual-level factors, including knowledge of RUM, attitudes toward RUM, self-efficacy, motivation for RUM, and work-related stress associated with medication delivery; (3) interpersonal-level factors, including communication with patients, physicians, pharmacists, and multidisciplinary teams; (4) organizational-level factors, including policies and practices, resource support, personnel development, work support systems, work environment, and workload; (5) community-level factors, including access to medications, community beliefs and culture, and community health networks; (6) policy-level factors, including national policies, professional laws and regulations, and patient care guidelines; and (7) competencies in RUM among NPs. Data collection was conducted between June and September 2025 in primary care units and through online distribution via Google Forms, achieving a 100% response rate. Data analysis employed descriptive statistics, Pearson’s correlation coefficients, and Stepwise multiple regression analysis.

Results The participants had a mean age of 39.14 years (SD = 10.43). The majority were female (56.25%), married (56.99%), and held a bachelor’s degree (95.22%). Most participants (70.59%) reported 1–10 years of experience in caring for patients with non-communicable diseases. Descriptive analysis indicated that all levels of factors within the socio-ecological framework were rated at high to very high levels. Stepwise multiple regression analysis identified eight significant predictors. The final model was statistically significant (F = 71.74, p < .001) and accounted for 67.6% of the variance in RUM competency (Adj. R² = .676; R = .828, R² = .686). Examination of standardized beta weights revealed that workload was the strongest negative predictor (β = -0.25, p < .001), followed by organizational policies and practices (β = 0.22, p < .001), knowledge of RUM (β = 0.18, p < .001), interprofessional communication (β = 0.14, p = .002), work-related stress (β = -0.10, p = .015), work support systems (β = 0.09, p = .028), self-efficacy in RUM (β = 0.08, p = .037), and experience in caring for patients with chronic diseases (β = 0.07, p = .049).

Recommendation The findings of this study support the development of nurse practitioners’ competencies in RUM through multi-level strategies. At the knowledge level, RUM content should be more explicitly integrated into both pre-service curricula and continuing professional development, with emphasis on knowledge application, self-confidence building, ethical decision-making, and interprofessional communication. At the practice level, administrators should strengthen work support systems to mitigate the impact of workload on medication-related decision-making. Examples include using information systems or clinical decision-support tools to screen for medication risks, alert providers to duplicate prescriptions or contraindications, and allocate additional nursing staff in primary care units or during high-risk periods. Work processes should also be redesigned to facilitate effective coordination. At the policy level, existing RUM guidelines should be translated into clear, practical, and contextually appropriate tools that can be readily applied within primary care services.