Objective: This study attempted to evaluate sensitivity, specificity and predictive values of the diagnosis of dementia made by trained community health workers.
Method: A total of 1,000 subjects over the age of 65 years were recruited for the study. The community health workers identified nine subjects as having dementia. This was compared against an education adjusted diagnosis of dementia made in accordance with the 10/66 dementia research group protocol.
Results: The sensitivity and specificity of the community health worker diagnosis was 3.8% and 99.4% respectively. The false positive rate and positive predictive values were 55.6% and 44.4%, respectively. The false negative rate and negative predictive value were 10.3% and 89.7% respectively. Similar values were obtained against a DSM IV diagnosis. Subjects with dementia who were correctly diagnosed by the community health workers and those whose condition was missed did not differ significantly on socio-demographic and clinical variables.
Conclusion: Informal screening by community health workers resulted in low sensitivity and positive predictive values. Screening strategies in situations of low prevalence are not effective.