Decisional capacity to consent to treatment and research in patients affected by Mild Cognitive Impairment. A systematic review and meta-analysis

Abstract

Objectives: To perform a meta-analysis of clinical studies on the differences in treatment or research decision-making capacity among patients with Mild Cognitive Impairment (MCI), Alzheimer’s disease (AD), and healthy comparisons (HCs). Design: A systematic search was conducted on Medline/Pubmed, CINAHL, PsycINFO, Web of Science, and Scopus. Standardized mean differences and random-effects model were used in all cases. Setting: The United States, France, Japan, and China. Participants: Four hundred and ten patients with MCI, 149 with AD, and 368 HCs were included. Measurements: The studies we included in the analysis assessed decisional capacity to consent by the MacArthur Competence Assessment Tool for Treatment (MAcCAT-T), MacArthur Competence Assessment Tool for Clinical Research (MacCAT-CR), Capacity to Consent to Treatment Instrument (CCTI), and University of California Brief Assessment of Capacity to Consent (UBACC). Results: We identified 109 potentially eligible studies from 1672 records, and 7 papers were included in the meta-analysis. The meta-analysis showed that there was significant impairment in a decision-making capacity in MCI patients compared to the HCs group in terms of Understanding (SMD = −1.04, 95% CI: −1.31 to −0.77, P < 0.001; I2 = 52%, P = 0.07), Appreciation (SMD = −0.51, 95% CI: −0.66 to −0.36, P < 0.001; I2 = 0%, P = 0.97), and Reasoning (SMD = −0.62, 95% CI: −0.77, −0.47, P < 0.001; I2=0%, P =0.46). MCI patients scored significantly higher in Understanding (SMD = 1.50, 95% CI: 0.91, 2.09, P = 0.01, I2 = 78%, P = 0.00001) compared to patients affected by AD. Conclusions: Patients affected by MCI are at higher risk of impaired capacity to consent to treatment and research compared to HCs, despite being at lower risk compared to patients affected by AD. Clinicians and researchers need to carefully evaluate decisional capacity in MCI patients providing informed consent.

Treatment preferences among adults with normal cognition and cognitive impairment

“…Respondents with cognitive impairment possibly had greater difficulty determining their treatment preferences. This finding supports prior research that cognitive impairment negatively impacts decisional capacity 6–11 . Greater uncertainty of treatment decisions for individuals with cognitive impairment warrants earlier discussions with all patients on end‐of‐life treatment preferences.…”

“…[6][7][8] A recent meta-analysis of seven studies found a reduced capacity to consent to medical treatment and research participation in persons with MCI. 8 Evidence suggests that those with MCI are generally deficient in important consent to treat capacity measures including appreciation, reasoning, and understanding. 6,9,10 One study found that around 40% of participants with MCI were considered incapable of consent.…”

What is at stake in decision-making capacity tools?

“…This study (Parmigiani et al, 2020) seems to show that the decision-making capacity of MCI patients could be overestimated due to an impairment of comprehension capacities.…”

“…A meta-analysis is published in this issue of International Psychogeriatrics titled "Decisional capacity to consent to treatment and research in patients affected by Mild Cognitive Impairment-A systematic review and meta-analysis" (Parmigiani et al, 2020). Its objective is to compare the ability to decide to take treatment or participate in clinical research of Mild Cognitive Impairment (MCI) patients versus Alzheimer's patients and patients without neurocognitive disorders.…”

Improving knowledge of capacity assessment

“…Achieving a balance between these two ethical imperatives is a profoundly important yet complex task. This issue comes up frequently for many mental health care providers, as a number of cognitive and other neuropsychiatric conditions may elevate the risk of impairment in decision-making capacity in one or more domains of independent functioning (Biella et al, 2020;Oshima et al, 2020;Parmigiani et al, 2021;Romdhani et al, 2020).…”