Prediction of Diagnosis of Dementia Using Cognitive Impairment Diagnosing Instrument(CIDI)

Park, Jonghan; Lee, Jonghun; Choi, Soon Ok

Abstract

OBJECTIVES
This study aimed at investigating the diagnostic predictability of Cognitive Impairment Diagnosing Instrument(CIDI) in diagnosing dementia of elderly people aged 60 years or more.
METHODS
The subjects were 129 patients with other mental diseases than dementia whose ages were more than 60 years and 86 patients with dementia. Psychiatric diagnoses were made by according to the DSM-IV criteria. Converted age(chronological age minus 59) was employed for the statistical reason. The length of education was classified into 4 intervals:1 for less than one year schooling, 2 for grade schooling, 3 for junior or senior high schooling and 4 for college or more schooling and each number expresses ordinal scale. The converted age, length of education expressed by one of 4 interval scores, and total CIDI score were independent variables while the diagnosis(dementia vs nondementia) was dependent variable in the logistic regression analysis.
RESULTS
-2 log likelihood was 102.773 when the length of education, converted age and total CIDI score were included while it was 289.395 when only the constant was included(K 2=186.622, df=3, p=0.000). The goodness-of-fit statistic was 156.798(K 2=6.5843, df=8, p=0.5821), and the overall concordance of diagnostic classification was 90.2%. The logistic regression equation for the diagnosis of dementia was generated as follows:y=7.5752+0.0940*X 1+0.9820*X 2-0.1811*X 3(y=ln{pai/(1-pai)}, X 1:converted age, X 2:education intervals, X 3:total CIDI score, pai:possibility of dementia, > OR =0.50 indicating dementia and <0.50 indicating nondementia). The e bs(95% C.I.) for the converted age, education interval and total CIDI score were 1.0985(1.0107-1.1940), 2.6699(1.4134-5.0436), 0.8344(0.7898-0.8815), respectively.
CONCLUSIONS
The CIDI could be considered as a useful diagnostic tool for dementia using the logistic regression analysis.