The informed consent process in older patients who developed delirium: a clinical epidemiologic study

Delirium, defined as an acute, fluctuating disorder of attention and cognition, is a serious and increasingly common problem for hospitalized older persons. Delirium poses unique ethical challenges for the informed consent process, notably the preservation of patient autonomy in the face of potentially fluctuating decision-making capacity. To clarify these issues, we examined the informed consent process in a group of hospitalized older patients who developed delirium.

Eighty-four hospitalized patients aged >70 years who developed delirium during hospitalization at a large urban teaching hospital.

We conducted a clinical epidemiologic investigation of informed consent in 173 medical and surgical procedures performed in 84 patients. Clinical researchers carried out detailed cognitive evaluation of patients on or near the consent date. A separate blinded researcher extracted medical record information on the procedures and informed consent process variables.

Of 173 procedures, 33 (19%) had no documentation of any consent, and 34 (20%) used surrogate consent. There were no documented assessments of competency/ decisional capacity; cognitive assessments were done in 7 (4%) cases, and legal consults in 2 (1%) cases. Discussion of potential risks of the procedure with patient or surrogate were documented in 61 (35%) cases. In multivariable analysis, independent predictors for failure to obtain consent were presence of delirium (adjusted odds ratio [OR] = 2.7, 95% confidence interval [CI] 1.3, 5.3) and less invasive procedure (OR = 5.0, CI 2.0, 12.8). Although cognitive impairment predicted surrogate use, we found that 47% of cases with substantial impairment did not involve use of a surrogate, whereas surrogates signed for 4% of cases with normal mental status near the time of consent.

Our results highlight the ethical challenges that delirium poses for the informed consent process, including the high rate of no consent, lack of cognitive and decisional capacity assessment, and inconsistent surrogate use.