|
Clinical Question:
Are patients with Parkinson's disease at increased risk of death
and dementia?
Bottom Line:
patients with Parkinson disease who carry an APOE epsilon2 allele have an
increased risk of developing dementia. Increased mortality risk in Parkinson
disease is dependent on disease duration and is only modest in the absence
of dementia.
Reference:
de Lau LM, Schipper CM, Hofman A, Koudstaal PJ, Breteler MM. Prognosis of
Parkinson disease: risk of dementia and mortality: the Rotterdam Study. Arch
Neurol 2005; 62:1265-69.
Study Design:
Cohort (prospective)
Funding:
Government
Setting:
Population-based
Synopsis:
In this study from the Netherlands, nearly 8000 people older than 55 years
were identified between 1990 and 1993. The researchers performed a whole
bunch of baseline evaluations including apolipoprotein E (APOE) genotyping
and formal assessments for Parkinson's disease and dementia. The research
team reassessed the patients in 1993-94 and 1997-99. They also continuously
monitored the patients using computerized linkages to the patients' primary
care physicians' electronic medical records. Until 2000, the researchers had
follow-up data on a remarkable 99% of the patients for more than 48,000
patient-years (mean follow-up = 6.9 years). In this group, 99 people had
Parkinson's disease at baseline and 67 were given a diagnosis after
inclusion. At baseline, 22% of the patients with Parkinson's disease -- and
4% of those without it -- were diagnosed with dementia. A total of 15% of
those with Parkinson's disease subsequently developed dementia compared with
5% of those without Parkinson's disease. This 3-fold ratio persisted after
adjusting for education, smoking, medication use, living situation, and APOE
genotype. Patients with at least one APOE epsilon4 allele were at a 6-fold
increased risk of developing dementia (95% CI, 3.1 - 12.8) and those
carrying an APOE epsilon2 allele were at greatest risk (hazard ratio = 13.5;
95% CI, 4.5 - 40.6). Ninety (54%) of the patients with Parkinson's disease
died compared with 1623 (24%) of those unaffected. The longer the duration
of Parkinson's disease, the greater the mortality risk.
|