ObjectiveWith the shortage of medical staff, the birth rate decline, and aging populations in some countries, task shifting from specific medical staff to non-medical care workers in hospitals has been implemented as a short-term solution. Incident reporting reduces preventable patient errors, improves the quality of healthcare services, and contributes to patient safety. However, research focused on the expanding roles of non-medical staff who provide direct care for patients is lacking. The present study aimed to bridge this gap by examining reported incidents involving non-medical care workers and nursery teachers in hospitals in Japan.MethodologyA retrospective mixed-methods study was conducted using data published by the Japan Council for Quality Health Care. A total of 21,876 cases were reported between 2016 and 2020, and 97 out of 21,876 cases were analysed, after excluding incidents involving workers or staff other than care workers/nursery teachers. Descriptive statistics were used to examine the incidents, and textual data included in the incident reports were analysed by two registered nurses.ResultsThe occupations of the people involved were care worker (n=80, 82.5%) and nursery teacher (n=17, 17.5%). There were two reports of worker injuries (n=2, 2.1%), which were excluded. A total of 95 cases were included in the final analysis to examine the effects on patients. Among the remaining 95 cases, there were five severe patient incidents (death, n=2, 2.1%; cerebral hemorrhage, n=3, 3.2%), and the most frequent incident was bone fracture (n=64, 67.4%). Some patients had cognitive impairment (n=29, 30.5%) and osteoporosis (n=25, 26.3%). We divided the factors related to incident occurrence into software (procedures and protocols), environment (wards and theaters), and liveware (people, including care workers, nursery teachers, and patients). Regarding the reasons for the incidents, the percentages for the three factors were as follows: education/training 34.7% (n=33), in software; patient state 4.1% (n=39), in environment; and neglect to observe 45.3% (n=43), in liveware.ConclusionOur study involved a secondary analysis of published data, and the sample size was small. However, incident reports from care workers and nursery teachers working in hospitals included serious errors. The role of non-medical care staff in hospitals is broad and diverse, and has been shifting from direct care for patients with mild illnesses to direct care for patients with severe illnesses. An efficient clinical environment that ensures quality of care and service is lacking. By focusing on patient safety outcomes, policymakers and hospital teams should consider adjusting the working environment.