Dementia survival rates improve across multiple countries, study shows

A person diagnosed with dementia has improved survival outcomes in recent years amid significant progress in dementia diagnosis and care, according to a recent multinational study led by a University of Waterloo researcher. 

The study analyzed data from more than 1.2 million people over the age of 60 living with dementia in eight global regions between 2000 and 2018. It found that in five of those regions, including Ontario, a lower risk of death exists today than in previous years. 

Dementia is a global public health priority. Understanding how survival among people living with dementia varies over time and across health systems can help policy makers assess its real-world impact on health and social care services." 

Dr. Hao Luo, assistant professor in the School of Public Health Sciences and lead author of the study

She said the increase in survival probability is likely due to factors such as progress in dementia prevention and care in recent years, as well as more effective drug treatments and psychosocial interventions tailored to an individual's needs. 

"Knowledge of survival after the diagnosis of dementia is important for people living with dementia and their family members for making informed decisions about the subsequent care arrangement, for clinicians to improve their prognosis and care for people living with dementia and for policy makers to improve estimation of the real-world disease burden currently carried by health systems," Luo said. 

Of the eight regions in the study (Ontario, United Kingdom, South Korea, Taiwan, Hong Kong, Finland, Germany and New Zealand), only New Zealand showed an increase in the risk of death following the first hospital record of dementia diagnosis. Data from Finland and Germany were inconclusive. 

"We were surprised to observe a steady increase in mortality risk in New Zealand between 2014 and 2018," Luo said. "We later found that this coincided with a national effort to shift the diagnosis and management of uncomplicated dementia to primary care to free up specialist services. With greater involvement of primary care, people living with dementia are more likely to present to hospitals at a more advanced stage of the disease, leading to a higher risk of mortality following the first hospital record of dementia diagnosis." 

The consistently observed decrease in mortality risk across five of the regions accounted for 84 per cent of all participants. Canada, the U.K., South Korea, Taiwan, Finland and Germany have national dementia strategies already in place or in development. 

Luo said her future research will look at the role comorbidities play. "To analyze multinational data using a standardized approach, some compromises were made, including not accounting for the impact of comorbid conditions on dementia survival," she said. "One of my future research directions is to understand the patterns of comorbidity and how comorbidities affect survival among persons with dementia."