Background
Prognostic uncertainty is one barrier to engaging in goals-of-care discussions in chronic kidney disease (CKD). The surprise question (“Would you be surprised if this patient died in the next 12 months?”) is a tool to assist in prognostication. However, it has not been studied in non–dialysis-dependent CKD and its reliability is unknown.
Study Design
Observational study
Setting & Participants
388 patients at least 60 years of age, with non–dialysis-dependent CKD stages 4–5, who were seen at an outpatient nephrology clinic.
Predictor
Trinary (i.e., ‘Yes’, ‘Neutral’, ‘No’) and binary (‘Yes’, ‘No’) surprise question response.
Outcomes
Mortality, test-retest reliability, and blinded inter-rater reliability
Measurements
Baseline comorbidities, Charlson comorbidity index, cause of CKD, and baseline laboratory values (i.e., serum creatinine/estimated glomerular filtration rate, serum albumin, and hemoglobin).
Results
The median patient age was 71 years with median follow-up of 1.4 years, during which time 52 (13%) patients died. Using the trinary surprise question, providers responded ‘Yes’, ‘Neutral’, and ‘No’ for 202 (52%), 80 (21%), 106 (27%) patients, respectively. About 5%, 15%, and 27% of ‘Yes’, ‘Neutral’, and ‘No’ patients died, respectively (p<0.001). The trinary surprise question inter-rater reliability was 0.58 (95% CI, 0.42–0.72) and the test-retest reliability was 0.63 (95% CI, 0.54–0.72). The trinary surprise question ‘No’ response had a sensitivity and specificity of 55% and 76%, respectively (95% CIs, 38%-71% and 71%-80%, respectively). The binary surprise question had a sensitivity of 66% (95% CI, 49%-80%; p=0.3 vs trinary) but a lower specificity of 68% (95% CI, 63%-73%; p=0.02 vs trinary).
Limitations
Single center, small number of deaths.
Conclusions
The surprise question associates with mortality in CKD stages 4–5 and demonstrates moderate to good reliability. Future studies should examine how best to deploy the surprise question to facilitate advance care planning in advanced non–dialysis-dependent CKD.