Medical device-related pressure injuries are receiving increased attention because their social and economic costs are increasing. This study aimed to analyse the stages for each risk factor, and to assess which has a greater impact on severity. We performed a retrospective analysis of 237 patients. Severity was evaluated by pressure injury stages, and the following categories were considered as risk factors: perceptual functioning, malnutrition, reduced mobility, comorbidities, extrinsic factors, medical devices, anatomical areas, and hospital stay. The stages of pressure injury stages were more for vascular access devices than for respiratory devices. The following were related to severity: mental deterioration-related diseases, mental status, albumin level, haemoglobin level, total cholesterol level, intensive care unit care, days of hospitalisation, and time to develop pressure injuries after admission. Decreased mental status, anaemia, hypoalbuminemia, and low total cholesterol levels were particularly critical. However, factors such as anatomical areas, age, malignancy, diabetes mellitus, diseases related to malnutrition, abnormal body mass index, immobility-related diseases, physical restraints, and Braden scale scores were not. A different approach to the management of medical device-related pressure injuries is necessary because they have distinctive characteristics and causative factors than other pressure injury types.