Information and competency for consent to pharmacologic clinical trials inAlzheimer disease: An empirical analysis in patients and family caregivers

This study was undertaken to evaluate (1) what information normal and Alzhe imer disease (AD) participants are able to manage; (2) the correlation betw een the degree of competency and age, education and dementia scores, and th e ability of dementia scores to predict incompetence; and (3) the capacity to retain consent-related information. To fulfil these aims, a four-point c ompetency rating scale (1 = incompetent, 2 = marginally competent, 3 = suff iciently competent, and 4 = completely competent) was used in 70 patients ( Mini-Mental State Examination [MMSE] score >9; Global Deterioration Scale s core <6) and in 40 cognitively normal caregivers. Patients Were divided int o two subgroup., (competency ratings 1 and 2 versus 3 and 4) to calculate p ositive and negative predictive values of MMSE and Alzheimer Disease Assess ment Scale-cognitive (ADAScog) for absent/marginal competence. Main results Were as follows: (1) 32.9% of AD patient, were "incompetent" (no caregiver s), 37.1% were "marginally competent" (20% caregivers), 18.6% were "suffici ently competent" (50%, caregivers), and 11.4% were "completely competent" ( 30% caregiverss). (2) Competency ratings and age did not correlate in AD, w hereas a negative correlation was significant in caregivers; competency rat ings positively correlated to education in caregivers. (3) ADAScog and MMSE were the tests most significantly correlated to competency; MMSE score bel ow 18 had a positive predictive value of 95% and a negative predictive valu e of 63.3%. The fact that 95% of patients with MMSE scores below 18 are inc ompetent or marginally competent points to an urgent need for ethical proce dures capable of creating a balance between difficulties in obtaining valid consent and a patient's fight to benefit from advances in clinical researc h.