Performance of the Surprise Question Compared to Prediction Models in Hemodialysis Patients: A Prospective Study

Abstract

Background: The surprise question (SQ) ("Would you be surprised if this patient were still alive in 6 or 12 months?") is used as a mortality prognostication tool in hemodialysis (HD) patients. We compared the performance of the SQ with that of prediction models (PMs) for 6- and 12-month mortality prediction.

Methods: Demographic, clinical, laboratory, and dialysis treatment indicators were used to model 6- and 12-month mortality probability in a HD patients training cohort (n = 6,633) using generalized linear models (GLMs). A total of 10 nephrologists from 5 HD clinics responded to the SQ in 215 patients followed prospectively for 12 months. The performance of PM was evaluated in the validation (n = 6,634) and SQ cohorts (n = 215) using the areas under receiver operating characteristics curves. We compared sensitivities and specificities of PM and SQ.

Results: The PM and SQ cohorts comprised 13,267 (mean age 61 years, 55% men, 54% whites) and 215 (mean age 62 years, 59% men, 50% whites) patients, respectively. During the 12-month follow-up, 1,313 patients died in the prediction model cohort and 22 in the SQ cohort. For 6-month mortality prediction, the GLM had areas under the curve of 0.77 in the validation cohort and 0.77 in the SQ cohort. As for 12-month mortality, areas under the curve were 0.77 and 0.80 in the validation and SQ cohorts, respectively. The 6- and 12-month PMs had sensitivities of 0.62 (95% CI 0.35-0.88) and 0.75 (95% CI 0.56-0.94), respectively. The 6- and 12-month SQ sensitivities were 0.23 (95% CI 0.002-0.46) and 0.35 (95% CI 0.14-0.56), respectively.

Conclusion: PMs exhibit superior sensitivity compared to the SQ for mortality prognostication in HD patients.

Keywords: Hemodialysis; Mortality; Prediction model; Surprise question.