Prognosis and vascular co-morbidity in dementia a historical cohort study in general practice

Background : Disease management of dementia in general practice (GP) is hampered by a lack of data on the prognosis of dementia. Aim : To gain more insight into the life expectancy of and the effects of cardiovascular and cerebrovascular co-morbidity in dementia patients in GP. Design of study : Historical cohort. Setting : 4 general practices in Nijmegen, The Netherlands. Population : All patients in these practices participating in the Continuous Morbidity Registration (CMR). Methods : The patient cohort was diagnosed with dementia between January 1st 1985 and December 31st 2002. The control cohort consisted of patients matched one-to-one with demented patients on age, sex, and socio-economic status. Cardiovascular and cerebrovascular co-morbidity was studied from 5 years before the diagnosis of dementia till the endpoints of data collection. Results : 251 couples of patients and controls were formed (79 men, 172 women, mean age 81.4 ± 7.0 years). The median life expectancy after diagnosis was 2.3 years for the dementia patients, and 3.7 years for the controls. Median time from diagnosis till nursing home placement was 1.4 years. Cerebrovascular and cardiovascular morbidity preceding dementia diagnosis decreased survival of cases with dementia with a relative risk of 1.54 (95%CI: 1.13–2.09) and in controls with a relative risk of 1.91 (95%CI: 1.48–2.46). Obesity was associated with a lower risk of dementia (RR=0.77 (95%-CI 0.63 – 0.94)). Hypertension and obesity diagnosed after the dementia diagnosis were significantly associated with an increase in survival. Conclusion : In general practice, the diagnosis of dementia is made at a late stage, when patients will continue to live at home only for a short time. Moreover, life expectancy at diagnosis is very limited and prognosis is furthermore negatively influenced by preceding cardio- and cerebrovascular co-morbidity.