Innovations in HCI research of health-related pervasive and ubiquitous technologies can potentially improve older adults’ access to healthcare resources and support long-term independence in the home. Despite efforts to include their voices in technology research and design, many older adults have yet to actualize these health benefits, with barriers of access and proficiency actually widening the gap of health inequities. We reviewed 174 HCI publications through a systematic review to examine who is engaged in the design of health technologies for older adults, methods used to engage them, and how different types of participation might impact design directions. Findings highlight that thus far, many identity dimensions have not been explored in HCI aging research. We identify research gaps and implications to promote expanding research engagement with these dimensions as a way to support the design of health technologies that see better adoption among marginalized populations.