  mHealth interventions show significant potential to help in the
self-management of chronic diseases, but their under use remains a problem.
Considering the substantial diversity among individuals dealing with chronic
diseases, tailored strategies are essential. \emph{Adaptive User Interfaces}
(AUIs) may help address the diverse and evolving needs of this demographic. To
investigate this approach, we developed an AUI prototype informed by existing
literature findings. We then used this prototype as the basis for focus group
discussions and interview studies with 22 participants managing various chronic
diseases, and follow-up surveys of all participants. Through these
investigations, we pinpointed key challenges related to the use of AUIs,
strategies to improve adaptation design, and potential trade-offs between these
challenges and strategies. Concurrently, a quantitative survey was conducted to
extract preferences for AUIs in chronic disease-related applications with 90
further participants. This uncovered participants' preferences for various
adaptations, data types, collection methods, and involvement levels. Finally,
we synthesised these insights and categories, aligning them with existing
guidelines and design considerations for mHealth app adaptation design. This
resulted in nine guidelines that we refined by a final feedback survey
conducted with 20 participants.
