Rationale & ObjectiveA response “no” (SQ-No) to the surprise question (SQ) of whether a clinician would be surprised if a dialysis patient died in the next 6 months is associated with a higher risk of all-cause death. It is uncertain what domains are intuitively assessed with SQ. We hypothesized that SQ would be assessing the patient’s frailty, malnutrition, or patient-perceived health-related quality of life in a cohort of patients on maintenance hemodialysis. Study DesignCohort study Setting & ParticipantsA multi-center study including 994 patients on maintenance hemodialysis in Japan Predictors1) SQ answered by nurses, 2) frailty by modified Cardiovascular Health Study criteria, 3) malnutrition as evaluated by Geriatric Nutritional Risk Index (GNRI), and 4) patient-perceived health-related quality of life examined by the 36 Item Short-Form Health Survey (SF-36) physical component summary (PCS). OutcomesAll-cause mortality Analytical ApproachCox proportional hazard models ResultsMedian age and dialysis vintage were 66 and 5.9 years, respectively, and 35.8% were female, and 39.6% had diabetic kidney disease. The prevalence of SQ-No and frailty was 19.7% and 45.9%. Medians GNRI and SF-36 PCS were 96.3 and 36.9, respectively. During follow-up for 5 years, 247 patients died. Each of SQ-No, being frail, a low GNRI, and a low SF-36 PCS was a significant predictor of a higher risk for mortality independent of potential confounders. SQ-No remained a significant predictor after further adjustment for frailty or GNRI, but SQ-No was no longer significant when adjusted for SF-36 PCS. LimitationsWe did not assess the agreement of responses to SQ between different raters. ConclusionsPredictive ability of SQ was closely related to SF-36 PCS in hemodialysis patients. SQ by nurses appears to assess the physical domain of patient-perceived health-related quality of life rather than objectively assessed frailty or malnutrition.