There is a substantial variation in healthcare spending and readmission rate for individuals having admissions to different hospitals. This study assessed how the community structure of physician collaboration networks that evolve during the period of providing healthcare services to hospitalised patients contribute to this variation. A physician collaboration network is said to have a community structure if the nodes (i.e. physicians) of that network can be easily grouped into sets of nodes such that each set of nodes is densely connected internally but sparsely connected between groups. This study constructed physician collaboration networks based on patient-sharing ties among physicians who provided healthcare services to hospitalised patients. An administrative health insurance claim dataset was utilised to extract patient-sharing ties among physicians. Simple linear regression models were estimated to assess the impact of the community structure of physician collaboration networks on the healthcare outcome measures (i.e. readmission rate and hospitalisation cost). From these models, this study found that the structure of a physician community has significant impact on readmission rate and hospitalisation cost. Healthcare administrators or managers could consider this finding in developing effective and efficient healthcare environments in their respective healthcare organisations.