Association between continuous deep sedation and survival time in terminally ill cancer patients

Purpose: Our study aimed to evaluate the association between CDS and survival time using the likelihood of receiving CDS to select a matched non-CDS group through an accurate measurement of survival time based on initiation of CDS. Methods: A retrospective cohort study was performed using an electronic database to collect data regarding terminally ill cancer patients admitted to a specialized palliative care unit from January 2012 to December 2016. We first used a Cox proportional hazard model with receiving CDS as the outcome to identify individuals with the highest plausibility of receiving CDS among the non-CDS group (n = 663). We then performed a multiple regression analysis comparing the CDS group (n = 311) and weighted non-CDS group (n = 311), using initiation of CDS (actual for the CDS group; estimated for the non-CDS group) as the starting time-point for measuring survival time. Results: Approximately 32% of participants received CDS. The most common indications were delirium or agitation (58.2%), intractable pain (28.9%), and dyspnea (10.6%). Final multiple regression analysis revealed that survival time was longer in the CDS group than in the non-CDS group (Exp(β), 1.41; P < 0.001). Longer survival with CDS was more prominent in females, patients with renal dysfunction, and individuals with low C-reactive protein (CRP) or ferritin, compared with their counterpart subgroup. Conclusions: CDS was not associated with shortened survival; instead, it was associated with longer survival in our terminally ill cancer patients. Further studies in other populations are required to confirm or refute these findings.