Swedish scientists explore direct association of dementia and ischemic stroke deaths

A great number of studies have consistently scrutinized the relation between dementia and stroke, with a multiple fold increase in the risk factor for death. Swedish scientists at Karolinska Institute, conducted a retrospective survey using patient data in the Swedish Dementia Registry to figure out such relationships through direct association of dementia and ischemic stroke (IS) deaths. Additionally, other recorded evidences e.g. cause of death, any co-occurring disease as well as use of different drugs had been obtained from Swedish nationwide health registers.

Criteria fixed by Dr. Subic et al. to measure the accurate death count attributable to stroke diagnoses included various sub-divisions; 1) stroke as a death cause with registered data in Swedish Stroke Register (Riksstroke) and 2) data correlated to diagnosis of dementia, with comparative analysis concerning patients dying from IS and registered in Riksstroke, patients dying from IS without being registered in Riksstroke and those dying from other causes.

The accurate percentages of death from years 2007-2014 have been calculated. Interestingly, out of the 49823 patients with dementia diagnosis (in primary care or specialist clinics), the death rate in 2014 was recorded to be 28.4%, indicating 8.3% reports of Ischemic Stroke in their death certificates and only 38.9% had been registered in Riksstroke. Of patients who died of IS, there were additionally 153 patients who had a Riksstroke registration more than a year preceding death, totaling 612 patients with a confirmed IS or 52% of those with IS mentioned on their death certificates. Additionally, the statistics indicated that 56.0% of patients died from IS and registered in Riksstroke died in hospital compared to 16.8% patients who died from IS without being registered in Riksstroke, and 25.1% who died from other causes.

Death cause in IS patients was documented as vascular dementia whilst other deaths had diagnosis of Alzheimer's dementia. Another significant diagnosis for IS patients' deaths was the consumption of cardiovascular medications. Conversely, no difference had been observed in the use of antidepressants, anxiolytics, antipsychotics, acetylcholinesterase inhibitors, hypnotics and memantine drugs amongst the groups.

A relatively high number of patients died from IS (as per death certificate record), but no data had been listed in Riksstroke in the year before death. The current study, thus, generates significant information to question the accuracy of death certificate stroke diagnoses, for deaths reported outside Swedish hospitals, in particular. The authors conclude that these results are concerning for health monitoring processes in the region as mortality data is an important metric for guiding heath care programs and framing adequate public health policies.