NEW YORK (Reuters Health) – Once elderly patients are diagnosed with Alzheimer’s disease, ethnicity and comorbidity appear to affect survival, investigators report in the November 4 issue of Neurology.

Led by Dr. Yaakov Stern, the research team at Columbia University Medical Center identified 323 incident cases of Alzheimer’s disease from a cohort of approximately 4300 Medicare recipients enrolled in the Washington Heights Inwood Columbia Aging Project in New York. The subjects were primarily Hispanic (55%), followed by African American (33%), and white (11%). Follow-up averaged 4.1 years (maximum 12.6 years).

Although overall median lifespan (92 years) and age at diagnosis (83 years) did not differ among racial/ethnic groups, median survival after diagnosis among Hispanics was 7.6 years, significantly longer than among whites (3.7 years) and African Americans (4.8 years).

A history of diabetes and hypertension both independently shortened survival. The multivariate adjusted hazard ratio for mortality during follow-up was 2.57 for comorbid hypertension and 1.99 for diabetes (p < 0.05 for both).

Age was also a significant predictor, with a median post-diagnosis survival of 9.9 years among those aged 67-74 years, 6.9 years among those 75-84 years, and 4.4 years among those aged 85-100 years (p < 0.0001).

In contrast to most other studies, the team did not detect any association between survival duration and gender, history of heart disease or malignancy, or presence of APOE-epsilon-4 alleles.

The latter finding, Dr. Stern’s group suggests, “may reflect a differential effect of epsilon-4 in the earlier stages of disease that is eclipsed by other factors (medical, social, or disease-related factors) later in the disease course.”

Reference:
Neurology 2008;71:1489-1495.