Background <p>Persons with dementia (PWD) and their carepartners must often make complex medical decisions, weighing the benefits of medical (surgical and non-surgical) interventions with uncertainty regarding outcomes, both dementia- and non-dementia related, in the short-term and long-term. This study informs gaps in clinical guidance for patient-centered decision-making about medical and surgical interventions for PWD and advancecare planning.</p> Methods <p>We conducted a qualitative study using thematic analysis based on semi-structured interviews with PWD and carepartners.</p> Results <p>We interviewed 30 participants (9 PWD, 21 carepartners). Four themes were identified (with related subthemes): 1) PWD and carepartners varied in using decision-making approaches for medical interventions for PWD (a) variations in views about decision-making load; (b) Progressive involvement of carepartners in ACP decision-making as cognition erodes; 2) medical intervention decisions were an inflection point to evaluate values for dyads and involved tradeoffs with implications for end-of-life care and quality of life 3) lack of discussion with clinical team about impact of medical interventions on dementia burdened dyads; 4) decisional quality was facilitated by: (a) a trusting relationship with clinicians; and (b) a multidisciplinary team approach.</p> Conclusion <p>Most patients with mild-to-moderate dementia and carepartners approach medical intervention decision-making guided by their understanding of the dementia prognosis, but the risks of medical interventions are often unaddressed in discussions with the clinical team, sometimes burdening dyads with undesirable consequences to their quality-of-life. Clinicians should provide dementia-related risks regarding medical intervention outcomes to best facilitate decision-making conversations and advance care planning.</p>