Indicators of Cognitive Impairment From a Medical Record Review: Correlations With Early (30-d) Readmissions Among Hospitalized Patients in a Nephrology Unit.

Background: Patients with end-stage renal disease have the highest 30-day hospital readmission rates of any medical condition. Previous research suggests that cognitive impairment contributes to readmission. It is important to identify patients at risk for early readmission, and this might be accomplished efficiently using medical record data.

Method: We reviewed the medical records of 100 patients with kidney disease (57 women, mean age = 61.2) who were hospitalized in the nephrology unit at an urban U.S. hospital. For each patient, we recorded easily available indicators of cognitive impairment along with other potential risk factors, and also recorded the number of 30-day readmissions over the past year.

Results: Half of the sample (n = 50) had at least 1 readmission (median = 0.5, range: 0-20). A lifetime history of delirium, which is a known marker of chronic cognitive impairment, was significantly related to readmissions, and several other impairment indicators (positive head imaging, history of seizures, and history of hypoxia) showed similar trends. A "cognitive impairment index" (positive for one or more variables possibly reflecting impaired central nervous system) was significantly related to the presence of a 30-day readmission, beyond the effects of a number of behavioral and medical covariates.

Conclusions: Easily accessible cognitive impairment markers, especially a known history of delirium, may be useful to identify patients in nephrology units who are at increased risk for early hospital readmissions. Interventions can be targeted to these patients with the goal of reducing the likelihood of readmissions and improving health care outcomes.