Background Oral fluid intake commonly reduces in advanced cancer patients as they approach the end of their lives. The relationship of oral fluid intake with thirst and survival has not been fully evaluated. Better understanding of how oral fluid intake affects physical health and clinical outcomes may enable health professionals to identify which patients require hydration-based support.

Aim To explore the association of oral fluid intake with thirst and survival in advanced cancer patients.

Method A secondary analysis of an observational study database of 90 patients with advanced cancer from a previous study by Nwosu et al 2016. Regression analysis evaluated the relationship between oral fluid intake and thirst, and examined the predictive properties of recorded variables. Kaplan-Meier analysis evaluated the relationship between survival and oral fluid intake. A Cox regression was used to adjust for potential confounding factors: performance status, metastatic disease and age.

Results Low fluid intake was significantly associated with increasing thirst severity (Beta=−0.223, p=0.037). Increasing morphine dose also corresponded with increasing thirst (Beta=0.250, p=0.025). Oral care regimes were present in n=39 (43.3%) and their use was associated with higher thirst scores (Beta=−0.200, p=0.051). Daily fluid intake was 0–499 ml in 27 (30%); 500–799 mls in 42 (46.7%); and >800 mls in 21 (23.3%) participants. Lower oral daily fluid intake was associated with shorter median survival (800 mls=172 days. p=0.004). Oral fluid was an independent predictor of survival following adjustment with cox regression.

Conclusion In this advanced cancer sample, oral fluid intake was a statistically significant predictor of survival. Patients with fluid intake of <800 mls/day had higher thirst and shorter survival compared to those drinking larger volumes. Future studies can aim to improve mouth care and fluid intake in patients drinking <800 mls/day, to examine if this improves clinical outcomes.