Which factors influence the decision of hospitals to provide procedures on an outpatient basis? –Mixed-methods evidence from Germany

Shifting care from the resource-intensive inpatient setting to the more economically efficient outpatient sector is being promoted internationally by policymakers. Financial incentives are a major focus of such efforts because low levels of hospital outpatient care are attributed to differences in payment for inpatient and outpatient services. In Germany, however, there is significant variation in the extent to which hospitals provide outpatient care despite a uniform payment system. Therefore, other factors must be influencing German hospitals' strategic decisions whether to offer outpatient care. While most research has focused on specific procedures or lacks empirical support, our study provides a comprehensive analysis of the factors beyond financial incentives that influence the provision of hospital outpatient services in Germany. We employed a mixed-methods approach, first contacting health care experts with in-depth knowledge of the hospital outpatient landscape to identify possible influencing factors and then conducting a comprehensive quantitative analysis of all German hospitals. Our findings suggest that policymakers seeking to promote hospital outpatient care should consider a broad range of factors. We found that a hospital's service mix, size, procedure volume, and emergency care infrastructure significantly affected the proportion of outpatient services it offered. Strategic hospital planning emphasizing specialization and adherence to minimum volume standards might therefore be a valuable policy tool. Our analysis also highlights the importance of demographic and socioeconomic factors, such as the regional share of single-person households, suggesting that a comprehensive policy framework should account for broader population characteristics and not just elements directly related to hospital care.