Objectives The aim of this study is to evaluate pain management adequacy based on the Pain Management Index (PMI), and its association with the Brief Pain Inventory (BPI) in advanced cancer inpatients to a palliative care unit.

Methods This is a quantitative study concerning advanced cancer inpatients in a specialised palliative care unit between June 2021 and February 2022. The BPI was applied, and analgesia was observed on the first (D1), third (D3) and seventh (D7) day of hospitalisation. Adequate analgesia was considered when PMI≥0.

Results A total of 104 patients were evaluated on D1, 68 on D3 and 45 on D7, with a mean age of 53.6 years (SD±14.1), most of them female (65.4%), with the most frequent primary tumour site located in the gastrointestinal tract (22.1%). The observed analgesia was adequate (PMI≥0) in 52.9% of all patients on D1, 95.6% on D3 and 100% on D7 (p value=0.012). The number of patients with moderate to severe pain interference in general activities (p value 0.012), mood (p value 0.014), walking ability (p value 0.047), normal work (p value 0.038) and pleasure of living (p value 0.025) decreased during hospitalisation.

Conclusions Pain is a prevalent and impacting symptom in patients undergoing palliative care. Thus, objective analgesic adequacy assessments in specialised services are required. These findings reinforce the importance of effective pain control and corroborate the importance of employing objective tools in evaluating medical services and improving quality of life of patients.