Time trend in Alzheimer diagnoses and the association between geographical distance to an Alzheimer clinic and Alzheimer diagnosis: A Danish nationwide study
METHODS: Data of all individuals aged 65+ years were identified from Danish nationwide administrative registers. Incidences of Alzheimer diagnoses were analysed with joinpoint regressions and hazard ratios (HRs) for Alzheimer diagnosis by distances to an Alzheimer clinic were analysed with Cox regressions.
RESULTS: In the period 2000-2009 the incidence of Alzheimer diagnoses increased from 79.8 to 152 per 100,000 individuals aged 65-74 years and from 343.1 to 982.3 per 100,000 individuals aged 75+ years. The annual incidence of Alzheimer diagnosis increased with 32.5% (95%CI: 7.1-63.8) among individuals aged 65-74 years from 2000-2002 and with 29.1% (95%CI: 11.0-50.2) among individuals aged 75+ years from 2000-2003. For both groups incidence during subsequent years stagnated (p-value: >0.05 for changes). Compared to individuals without an Alzheimer diagnosis in the period 2008-2009, individuals diagnosed with Alzheimer’s disease had a shorter distance to an Alzheimer Clinic (16.6 vs.19.1 km, p-value: <0.001), higher mean age (80.7 vs. 73.7 years, p-value: <0.001) and were more often females (63.1 vs. 55.9 %, p-value: <0.001). Compared to individuals with 0-19 kilometres (km) to an Alzheimer clinic, the HR for an Alzheimer diagnosis was 0.80 (CI 95%: 0.70-0.92) at 20-39 km and 0.65 (CI 95%:0.52-0.81) at 40-59 km.
CONCLUSIONS: The inverse association between geographical distance to Alzheimer clinics and Alzheimer diagnoses suggests that distance exclude a segment of the elderly population from an appropriate diagnostic workup and treatment.