Opioid medications and longitudinal risk of delirium in hospitalized cancer patients

BACKGROUND. Delirium is an important problem in hospitalized cancer patients. The objective of this study was to determine whether exposure to corticosteroids, benzodiazepines, or opioids predicted delirium. METHODS. A prospective cohort study was conducted in an oncology/internal medicine population. Patients were assessed continuously for the presence of delirium until they were discharged by using the Nursing Delirium Screening Scale (Nu-DESC). Follow-up for outcome began after incident delirium. The primary outcome was the presence of a delirium event, which was defined as a Nu-DESC score > 1. Strengths of associations of medications with delirium were expressed as odds ratios (ORs) in univariate and multivariate analyses. RESULTS. in total, 114 patients (1823 patient-days) met the inclusion criteria for the study. The mean follow-up from incident delirium was 16 days. The mean number of delirium events by patient was 6 (total number, 667 delirium events). Analysis by day on several occasions revealed significant associations between opioids and delirium. Corticosteroids and benzodiazepines were not associated significantly with an increased risk of delirium on any given day. Analysis by patient using generalized estimating equation (GEE) models showed an increased risk of delirium on any day of follow-up associated with opioid exposure in univariate analysis (OR of 1.70; P < .0001). The association remained significant after adjustment for corticosteroid, benzodiazepine, and antipsychotic exposure using GEE regressions (OR of 1.37; P = .0033). Truncating follow-lip at 30 days did not affect the results (OR of 1.38; P < .032). CONCLUSIONS. Exposure to opioids during hospitalization was associated significantly with an increased longitudinal risk of delirium.