The Effect of Heat and Cold Waves on the Mortality of Persons with Dementia in Germany

We investigated whether persons with dementia (PwD) are at particular risk of mortality when exposed to extreme temperatures and whether the temperature effect depends on long-term care (LTC) need and residency. German health claims data provide information on inpatient and outpatient sectors. Data from the German Meteorological Service were merged, and measures of immediate and delayed heat, cold, and normal temperature (Heat Index, Wind Chill Temperature Index) were calculated. Cox models were applied to explore the interaction of temperature, dementia, and LTC, as well as residency. Immediate and delayed effects of heat and cold were tested as compared to normal temperatures. Models were adjusted for age, sex, comorbidities, urban/rural living, and summer/winter climate zones. The 182,384 persons aged ≥65 contributed 1,084,111 person-years and 49,040 deaths between 2004 and 2010. At normal temperatures, PwD had a 37% (p-value < 0.001) increased mortality risk compared to persons without dementia (PwoD). Immediate heat effects further increased this effect by 11% (p = 0.031); no immediate heat effect existed for PwoD. The immediate heat effect was even greater for PwD suffering from severe or extreme physical impairment and for those living in private households and nursing homes. Immediate and delayed cold effects increased mortality independent of dementia. Care level and type of residency did not modify this effect among PwD. PwD revealed an increased vulnerability to immediate heat effects. Cold waves were risk factors for both groups. LTC need appeared to be an important intervening factor.