Consensus definition of clinical complexity in palliative care: a two-round Delphi Study with a National Multidisciplinary Panel

Objective This study aimed to: (1) develop a consensus definition of clinical complexity in adult patients with palliative care (PC) needs, adapted to the Portuguese health system context; (2) identify core determinants; (3) compare agreement between expert and non-expert professionals in a context where no standardised definition of clinical complexity in palliative care (PC) currently exists. Methods A two-round Delphi study included 79 professionals in round 1, with 57 completing round 2, comprising experts (R1/R2: 52/43) and non-experts (27/14). Consensus was defined as ≥70% of responses in the top two categories of a 5-point Likert scale. Qualitative data were analysed by independent thematic analysis with two coders (κ=0.97). Results All core elements of the revised definition achieved consensus (R2): profound suffering (97%), clinical unpredictability (95%), caregiver network (91%), complexity arising from a single dominant factor (84%) and practical examples (81%). The proposed short definition achieved overall agreement of 75%, with higher consensus for clinical relevance (91%) and comprehensiveness (86%) than for clarity (77%). Four thematic clusters were identified: experiential and subjective dimensions, systemic and access-related determinants, relational and social determinants and operationalisation requirements. Conclusions This study proposes the first consensus definition of clinical complexity in PC in the Portuguese context—multidimensional, dynamic and centred on profound suffering, clinical unpredictability and the interactions between clinical, relational and systemic determinants, also providing a framework for instrument development, clinical referral improvement and international harmonisation of complexity assessment in PC.