KPIs and success factors for patient engagement with digital tools

A new study found that 88% of hospitals and health systems are investing in digital patient engagement tools to empower patients in their health management. As healthcare evolves to a more patient-centric model, digital tools will need to be more and more engaging to thrive in this competitive industry. What are the main KPIs, financial and non-financial, to measure success in digital patient engagement? How do you mindfully, equitably and business-savvily build  business models around engaging and supporting patients? What are some good examples of KPIs that go beyond numbers of users or downloads?