Complexity of patients with or without infectious disease consultation in tertiary-care hospitals in Germany

Purpose Patients seen by infectious disease (ID) specialists are more complex compared to patients treated by other subspecialities according to Tonelli et al. (2018). However, larger studies on the complexity of patients related to the involvement of ID consultation services are missing. Methods Data of patients being treated in 2015 and 2019 in four different German university hospitals was retrospectively collected. Data were collected from the hospitals' software system and included whether the patients received an ID consultation as well as patient clinical complexity level (PCCL), case mix index (CMI) and length of stay (LOS) as a measurement for the patients' complexity. Furthermore, a comparison of patients with distinct infectious diseases treated with or without an ID consultation was initiated. Results In total, 215.915 patients were included in the study, 3% (n = 6311) of those were seen by an ID consultant. Patients receiving ID consultations had a significantly (p < 0.05) higher PCCL (median 4 vs. 0), CMI (median 3,8 vs. 1,1) and deviation of the expected mean LOS (median 7 days vs. 0 days) than patients in the control group. No differences among hospitals or between years were observed. Comparing patients with distinct infectious diseases treated with or without an ID consultation, the differences were confirmed throughout the groups. Conclusion Patients receiving ID consultations are highly complex, frequently need further treatment after discharge and have a high economic impact. Thus, ID specialists should be clinically trained in a broad spectrum of diseases and treating these complex patients should be sufficiently remunerated.