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(beta), 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.