Alzheimer's Disease International says most people with dementia receive a late diagnosis, if at all, resulting in a substantial "treatment gap."
The London-based group, which released its 2011 World Alzheimer Report early Tuesday, says as many as three-quarters of the estimated 36 (m) million people worldwide living with dementia haven't been diagnosed.
The report says failure to diagnose Alzheimer's often results from the false belief that dementia is a normal part of aging. But drugs and psychological interventions for people with early-stage dementia, it says, can improve cognition, independence, and quality of life.
The report adds that support and counselling for caregivers can improve mood, reduce strain and delay the institutionalization of people with dementia. In addition, governments, concerned about the rising costs of long-term care linked to dementia, should "spend now to save later."
Based on a review of economic analyses, the report estimates that earlier diagnosis could yield net savings of up to 10-thousand dollars U-S per patient in developed countries.
The main author of the study, Prof. Martin Prince at the Institute of Psychiatry, King's College London, says there is no single way to close the treatment gap worldwide.
What is clear, says Prince, is that every country needs a national dementia strategy that promotes early diagnosis and a continuum of care thereafter.
"Failure to diagnose Alzheimer's in a timely manner represents a tragic missed opportunity to improve the quality of life for millions of people," said Dr. Daisy Acosta, chairwoman of Alzheimer's Disease International.
"It only adds to an already massive global health, social, and fiscal challenge."
The report, titled "The Benefits of Early Diagnosis and Intervention," says in high-income countries, only 20-50 per cent of dementia cases are recognized and documented in primary care. In low- and middle-income countries, this proportion could be as low as 10 per cent.
The 2009 World Alzheimer Report estimated the number of people with dementia was expected to nearly double every 20 years — from 36 million in 2010 to 115 million in 2050.