Occurrence, Causes, and Outcome of Delirium in Patients With Advanced Cancer: A Prospective Study

Abstract

CONTEXT: Delirium impedes communication and contributes to symptom distress in patients with advanced cancer. There are few prospective data on the reversal of delirium in this population. OBJECTIVES: To evaluate the occurrence, precipitating factors, and reversibility of delirium in patients with advanced cancer. DESIGN: Prospective serial assessment in a consecutive cohort of 113 patients with advanced cancer. Precipitating factors were examined using standardized criteria; 104 patients met eligibility criteria. SETTING: Acute palliative care unit in a university-affiliated teaching hospital. MAIN OUTCOME MEASURES: Delirium occurrence and reversal rates, duration, and patient survival. Strengths of association of various precipitating factors with reversal were expressed as hazard ratios (HRs) in univariate and multivariate analyses. RESULTS: On admission, delirium was diagnosed in 44 patients (42%), and of the remaining 60, delirium developed in 27 (45%). Reversal of delirium occurred in 46 (49%) of 94 episodes in 71 patients. Terminal delirium occurred in 46 (88%) of the 52 deaths. In univariate analysis, psychoactive medications, predominantly opioids (HR, 8.85; 95% confidence interval [CI], 2.13-36.74), and dehydration (HR, 2.35; 95% CI, 1.20-4.62) were associated with reversibility. Hypoxic encephalopathy (HR, 0.39; 95% CI, 0.19-0.80) and metabolic factors (HR, 0.44; 95% CI, 0.21-0.91) were associated with nonreversibility. In mulitivariate analysis, psychoactive medications (HR, 6.65; 95% CI, 1.49-29.62), hypoxic encephalopathy (HR, 0.32; 95% CI, 0.15-0.70), and nonrespiratory infection (HR, 0.23; 95% CI, 0.08-0.64) had independent associations. Patients with delirium had poorer survival rates than controls (P<.001). CONCLUSIONS: Delirium is a frequent, multifactorial complication in advanced cancer. Despite its terminal presentation in most patients, delirium is reversible in approximately 50% of episodes. Delirium precipitated by opioids and other psychoactive medications and dehydration is frequently reversible with change of opioid or dose reduction, discontinuation of unnecessary psychoactive medication, or hydration, respectively.