Factors predicting the risk of loss of decisional capacity for medical assistance in dying: a retrospective database review.

BACKGROUND: Bill C-14, the legislation that legalized medical assistance in dying (MAiD) in Canada in 2016, outlines eligibility criteria and includes both a mandated 10-day reflection period and a requirement that the patient have capacity to consent at the time MAiD is provided. We examined clinical factors associated with shortened reflection periods or loss of capacity before provision of MAiD.

METHODS: This retrospective database review involved patients who requested MAiD at a tertiary care hospital in Toronto, Canada, between June 2016 and April 2019. We used logistic regression analyses to examine the association between the combined outcome of unanticipated loss of decisional capacity, shortening of the reflection period or death and the clinical risk factors of interest (age, sex, location of MAiD request [inpatient v. outpatient], score on palliative performance scale [PPS] and diagnosis [cancer v. noncancer]). We generated receiver operating characteristic curves to identify the PPS score (encompassing 5 functional domains: ambulation, activity level, self-care, intake and level of consciousness) that best predicted loss of capacity, shortening of the reflection period or death.

RESULTS: In total, 155 patients requested assessment for MAiD, and 136 of these were included in the statistical analyses. For 68 patients, the reflection period was not shortened; the other 68 patients lost capacity, died or required shortening of the reflection period. In contrast to the results for age, sex, location of request and diagnosis, the PPS score was associated with loss of capacity or shortening of the reflection period (odds ratio 4.63, 95% confidence interval 2.87-8.23, per 10-point decrease in PPS score). PPS scores less than or equal to 40% balanced sensitivity, specificity and negative predictive value while emphasizing sensitivity to prevent false negative errors.

INTERPRETATION: The PPS score at the time of MAiD request was strongly associated with loss of capacity or shortening of the reflection period, with lower scores incrementally increasing the risk of these outcomes. For patients with a PPS score of 40% or below, close monitoring is warranted, potentially with plans made to allow rapid provision of MAiD should their clinical condition deteriorate.