Numeracy and Interpretation of Prognostic Estimates in Intracerebral Hemorrhage Among Surrogate Decision Makers in the Neurologic ICU

Objective: Clinicians caring for patients with intracerebral hemorrhage must often discuss prognosis and goals of care with their patients’ surrogate decision makers, and may make numeric estimates of likelihood of survival and functional independence, informed by validated prediction models. Surrogates’ prognostic estimates are often discordant with physicians’, suggesting that physicians’ numeric statements may not be accurately interpreted. We sought to assess the relationship between numeracy and interpretation of prognostic estimates in intracerebral hemorrhage among surrogate decision makers. We also assessed surrogates’ application of prognostic estimates to decisions regarding goals of care. Design: Single-center, survey-based, cross-sectional study. Setting: Twenty-two–bed neurologic ICU at an urban, academic hospital. Subjects: Surrogate decision makers for patients admitted to the neurologic ICU. Interventions: Participants completed a survey containing five clinical vignettes describing patients with nontraumatic intracerebral hemorrhage. For each patient, numerical estimates of survival and functional independence were explicitly provided, based on the validated outcome risk stratification scale (intracerebral hemorrhage score) and the Prediction of Functional Outcome in Patients with Primary Intracerebral Hemorrhage score. Measurements and Main Results: Participants were asked to make their own prognostic estimates, as well as to describe their preferred goals of care for each hypothetical patient. Respondent demographics were collected, and numeracy was assessed using a modified Lipkus 11-item scale. Poor numeracy was common (42 of 96 total subjects) in this relatively highly educated population. Most prognostic estimates (55%) made by surrogates were discordant with the provided estimates. High numeracy correlated with better concordance (odds ratio, 23.9 [5.57–97.64]; p < 0.001), independent of several factors, including level of education and religion. Numeracy also affected goals-of-care decisions made by surrogates. Conclusions: Poor numeracy is common among surrogate decision makers in an intensive care setting and poses a barrier to communication between surrogates and clinicians regarding prognosis and goals of care.