Structure and dynamics of online patients’ communities: the case of Asthma UK and BLF online fora

Background: There is evidence that taking part in online patients9 communities facilitates disease self-management and improves people9s illness experience. However, little is known about the structure and evolution of online patients’ communities. Aim: The aim of this work was exploring this knowledge gap. Methods: We conducted network analysis of anonymised data from two UK online patients’ communities, Asthma UK (2006-2016) and British Lung Foundation (BLF, 2012-2016). Results: Activity grew over time in both communities. The time between posts followed temporal patterns consistent with symptoms exacerbations and disease trajectories of the underlying conditions. Both communities formed of a “giant component”, i.e. a connected subset of mutually reachable users. Removal of 1% and 5% of the most connected users (super-users) in the Asthma UK and BLF fora, respectively, made the giant component collapse, showing that the network was held together by very few individuals. Well-connected users tended to avoid each other and communicate with users who were not equally well-connected. Conclusions: This is the first study to examine the structure and dynamics of online patients’ communities, showing the emergence of important structural properties related to the way users communicate and engage in online activities. Further research is needed to explore tie formation mechanisms and network determinants of effectiveness of online engagement with respect to health-related outcomes.