Stump TE, Callahan CM, Hendrie HC. Cognitive impairment and mortality in older primary care patients.
J Am Geriatr Soc 2001;49:934-41.
OBJECTIVE: To assess the impact of cognitive impairment on mortality among elderly primary care patients after
controlling for confounding effects of demographic and comorbid chronic conditions.
DESIGN: Prospective cohort study.
SETTING: Academic primary care group practice.
PATIENTS: 3957 patients aged 60 years and older who completed the Short Portable Mental Status Questionnaire (SPMSQ)
during routine office visits.
MEASUREMENTS: Cognitive impairment measured at baseline using the SPMSQ; demographics, problem drinking, history of
smoking, clinical data (including weight, cholesterol level, and serum albumin), and comorbid chronic conditions collected
at baseline; survival time measured during the 5-7 years after baseline.
RESULTS: 886 patients (22.4%) died during the 5-7 years of follow-up. Cognitive impairment was categorized as
having no impairment (84.3%), mild impairment (10.5%), and moderate to severe impairment (5.2%) based on SPMSQ score.
Chi-square tests revealed that patients with moderate to severe impairment were significantly more likely to die compared
to patients with mild impairment (40.8% vs. 21.5%) as well as those with no impairment (40.8% vs. 21.4%). No significant
difference in crude mortality was found between patients with no impairment and those with mild impairment. After
analyzing time to death using the Kaplan-Meier method, patients with moderate to severe cognitive impairment were at
increased risk of death compared to those with no or mild impairment (Log-rank (2=55.5; p < .0001). Even in multivariable
analyses using Cox proportional hazards to control for confounding factors, compared to those with no impairment,
moderate to severely impaired patients had an increased risk of death with a hazard ratio (HR) of 1.70. Increased risk of
death was also associated with older age (HR=1.03 for each year), a history of smoking (HR=1.48), having a serum albumin
level < 3.5 g/L (HR=1.29), and weighing less than 90% of the ideal body weight (HR=1.98). Outpatient diagnoses associated
with increased mortality risk were diabetes, coronary artery disease, congestive heart failure, cerebrovascular disease,
cancer, anemia and chronic obstructive pulmonary disease (HR range from 1.36 to 1.67). Factors protective of mortality
risk included female gender (HR=0.67) and black race (HR=0.73).
CONCLUSIONS: Moderate to severe cognitive impairment is associated with an increased risk in mortality, even after
controlling for confounding effects of demographic and clinical characteristics. Mild cognitive impairment is not
associated with mortality risk but a longer follow-up period may be necessary to identify this risk if it exists.
Email us comments or suggestions