Serum albumin level and physical disability as predictors of mortality in older persons

Abstract

Objectives: To study the relationship between serum albumin level and all-cause mortality in an elderly population and to evaluate the role of albumin level in combination with physical disability status in predicting mortality.

Design: Cohort study with a mean follow-up of 3.7 years.

Setting: Three communities: East Boston, Mass, New Haven, Conn, and Iowa and Washington counties, Iowa.

Subjects: A total of 1486 men and 2630 women aged 71 years and older who consented to have blood drawn.

Results: During follow-up, 447 men and 488 women died. In both sexes, there was a graded increase in mortality rate with decreasing albumin level. After adjusting for age, race, education, chronic conditions, and disability status, hypoalbuminemia (< 35 g/L) was associated with a significantly increased risk of mortality in comparison with the reference group (ie, those with albumin levels greater than 43 g/L) (men: relative risk [RR], 1.9; 95% confidence interval [CI], 1.1 to 3.1; women: RR, 3.7; 95% CI, 2.5 to 5.5). Among those with albumin levels in the range usually considered normal (35 g/L to 50 g/L), there was a graded increase in mortality risk from the highest normal to the lowest normal groups. For women, results were similar in separate analyses that considered deaths occurring during the first year and 1 year or more after baseline, while for men the relationship decreased after 1 year. Lower albumin level was associated with an elevated risk of mortality for all categories of causes of death. A 15-level measure that characterized participants according to albumin level and disability status demonstrated that mortality increased with decreasing albumin level and increasing disability level.

Conclusions: Serum albumin level is an independent risk factor for all-cause mortality in older persons. A combined measure of albumin and disability reveals a strong gradient in mortality risk and may serve as a simple but useful index of frailty that can identify a high-risk group of older men and women who could be targeted for preventive and treatment efforts.