Between Knowledge and Care: Evaluating Generative AI-Based IUI in Type 2 Diabetes Management Through Patient and Physician Perspectives

Generative AI systems are increasingly adopted by patients seeking everyday health guidance, yet their reliability and clinical appropriateness remain uncertain. Taking Type 2 Diabetes Mellitus (T2DM) as a representative chronic condition, this paper presents a two-part mixed-methods study that examines how patients and physicians in China evaluate the quality and usability of AI-generated health information. Study~1 analyzes 784 authentic patient questions to identify seven core categories of informational needs and five evaluation dimensions -- \textit{Accuracy, Safety, Clarity, Integrity}, and \textit{Action Orientation}. Study~2 involves seven endocrinologists who assess responses from four mainstream AI models across these dimensions. Quantitative and qualitative findings reveal consistent strengths in factual and lifestyle guidance but significant weaknesses in medication interpretation, contextual reasoning, and empathy. Patients view AI as an accessible ``pre-visit educator,'' whereas clinicians highlight its lack of clinical safety and personalization. Together, the findings inform design implications for interactive health systems, advocating for multi-model orchestration, risk-aware fallback mechanisms, and emotionally attuned communication to ensure trustworthy AI assistance in chronic disease care.