Primary healthcare workers' work motivation is closely related to the quality and accessibility of health services. Autonomous motivation represents a higher-quality form of motivation, yet it is not fixed and may change with factors such as career experience and the institutional context, thereby exerting potential effects on work-related outcomes.

Drawing on Self-determination Theory (SDT), this study compared primary healthcare workers' initial (entry) motivation for practicing medicine with their current work motivation to describe changes in autonomous motivation (i.e., engaging in an activity based on full willingness and autonomous choice) and to examine the reasons for such changes and their associations with key work outcomes.

A mixed-methods design was adopted. Using multistage cluster sampling, we selected three cities in Shandong Province, China (Yantai in the east, Zibo in the central region, and Liaocheng in the west). In each city, three districts/counties were selected, and four primary healthcare institutions were sampled within each district/county, yielding 36 survey sites. On the survey day, all on-duty healthcare workers (including physicians, nurses, public health workers, and medical technicians) were invited to complete a questionnaire. Of 1 271 questionnaires distributed, 1 113 were valid (effective response rate: 87.6%). In addition, 107 participants were purposively sampled for in-depth interviews. Initial motivation for practicing medicine was measured using a self-developed questionnaire, while current work motivation was assessed with a revised Work Motivation Scale. Based on SDT, both initial and current motivations were classified into two types: autonomous motivation and non-autonomous motivation. By comparing the dominant type of initial and current motivation, a "motivation change" variable was constructed, yielding four categories. Four key indicators of work attitudes and behaviors were assessed: turnover intention, job burnout, job satisfaction, and job performance. Questionnaire data were analyzed using descriptive statistics, analysis of variance (ANOVA), and multiple linear regression. Interview data were analyzed using the thematic framework approach.

For initial motivation, 545 (49.0%) participants were classified as having autonomous motivation and 568 (51.0%) as having non-autonomous motivation. For current work motivation, 713 (64.0%) participants had autonomous motivation and 400 (36.0%) had non-autonomous motivation. The 2×2 "motivation change" variable produced four categories: stable autonomous motivation (n=403, 36.2%), stable non-autonomous motivation (n=258, 23.2%), autonomization (n=310, 27.8%), and de-autonomization (n=142, 12.8%). Scores for turnover intention, job burnout, job satisfaction, and job performance differed significantly across the four categories (all P<0.05). Specifically, compared with the stable autonomous motivation group and the autonomization group, the stable non-autonomous motivation group and the de-autonomization group reported higher turnover intention and job burnout (P<0.05) and lower job satisfaction and job performance (P<0.05). In addition, the autonomization group had higher turnover intention and job burnout (P<0.05) and lower job satisfaction and job performance (P<0.05) than the stable autonomous motivation group. Multiple linear regression indicated that, relative to the stable autonomous motivation group, the other three groups had higher regression coefficients in the models for turnover intention and job burnout (P<0.05) and lower regression coefficients in the models for job satisfaction and job performance (P<0.05). Interview findings suggested that changes in motivation were mainly influenced by the needs for meaning, competence, and relatedness.

Autonomous motivation is associated with better work performance among primary healthcare workers. Greater resource investment and institutional improvements are needed to foster a more supportive organizational context—such as strengthening health information systems, improving training mechanisms, and innovating doctor-patient communication-to satisfy primary healthcare workers' basic psychological needs and thereby enhance autonomous motivation.