Elsevier

The American Journal of Medicine

Volume 130, Issue 12, December 2017, Pages 1465.e11-1465.e19
The American Journal of Medicine

Clinical Research Study
Low Albumin Levels Are Associated with Mortality Risk in Hospitalized Patients

https://doi.org/10.1016/j.amjmed.2017.07.020Get rights and content

Abstract

Background

The aim of this study was to investigate the association of albumin levels on admission and change in levels during hospitalization with hospitalization outcomes.

Methods

Historical prospective data of patients hospitalized between 2011 and 2013 were collected. Levels of albumin were classified as marked hypoalbuminemia (<2.5 mg/dL), mild hypoalbuminemia (2.5-3.5 mg/dL), normal albumin (3.5-4.5 mg/dL), and hyperalbuminemia (>4.5 mg/dL). Main outcomes were length of hospitalization, in-hospital mortality, and long-term mortality.

Results

The cohort included 30,732 patients (mean age 67 ± 18 years, 51% male). Most patients had normal albumin levels on admission (n = 20,124, 65%), 29% of patients had hypoalbuminemia, mostly mild (n = 7,334, 24%), and 5% of patients had marked hypoalbuminemia (n = 1436). Hyperalbuminemia on admission was evident in 6% of the patients (n = 1838). Follow-up (median ± standard deviation) was 1675 ± 325 days. Compared with in-hospital mortality with normal albumin on admission (2%), mortality was higher with mild (12%) and marked hypoalbuminemia (34%) and lower with hyperalbuminemia (0.3%). Mortality rate at the end of follow-up was 29% with normal albumin levels, 67% and 83% with mild and marked hypoalbuminemia, respectively. Patients with hyperalbuminemia on admission and before discharge have the best short- and long-term survival. This pattern was similar when analyzed separately in different age groups. In patients with hypoalbuminemia on admission, normalization of albumin levels before discharge was associated with better short- and long-term survival, compared with patients with hypoalbuminemia before discharge.

Conclusions

Low albumin levels on admission are associated with increased short- and long-term mortality. Normalization of albumin levels before discharge was associated with lower mortality risk, compared with hypoalbuminemia before discharge.

Introduction

Albumin, a major component of plasma protein, is required to maintain oncotic pressure, microvascular permeability, acid–base function, and to prevent platelet aggregation.1 Serum albumin is an important parameter in the assessment of the nutritional status of both acute and chronically ill patients.2

The frequency of hypoalbuminemia, defined as serum albumin levels <3.5 g/dL, was 21% at the time of admission in adult hospitalized patients.3 De novo hypoalbuminemia and worsening of existing hypoalbuminemia are also common.4 Low albumin levels have been associated with morbidity and mortality in various populations, including patients with acute myocardial infarction,5 heart failure,6 stroke,7, 8, 9 renal disease,10, 11 hip fracture,12 and malignancies.13, 14, 15, 16 Vincent et al.17 identified low albumin as a dose-dependent and independent predictor of a poor outcome in patients with acute illness. However, there are conflicting reports throughout the literature regarding the importance of albumin levels.18, 19, 20 Causality is the main controversy, and the main questions are whether low albumin levels directly contribute to increased morbidity and mortality and the role of albumin therapy.17

Albumin is not an essential protein for immediate survival; hence, in malnourished or acute illness hepatic production of albumin decreases with a decrease of serum albumin levels.21 Herrmann et al.3 reported that low serum albumin levels obtained within 48 hours of admission were associated with increased length of stay and in-hospital mortality. However, because albumin levels may decrease early with severe illness, levels obtained 48 hours after admission may be lower than admission levels.3, 21

In the present study with a large cohort of patients hospitalized to medical wards, the association between albumin levels and important hospitalization outcomes, including length of admission, all-cause in-hospital mortality, and mortality at the end of follow-up (up to 6 years) was evaluated.

Section snippets

Methods

The study was conducted in a large, 1300-bed, university-affiliated, tertiary medical center. Most admissions to the 10 medical wards are through the emergency department. Historical prospective collected data were extracted from the medical records of all patients admitted for any cause to the hospital's medical wards between January 1, 2011 and December 31, 2013. Mortality data according to the population registry of the Ministry of the Interior were obtained up to February 1, 2017.

Study Cohort

There were 73,796 admissions to the 10 medical wards during the study period. After exclusion of repeat admissions (38,486 admissions) and patients with no measurement of albumin values within 24 hours of admission or before discharge (4578 patients), the final study cohort consisted of 30,732 patients. Mean age of the cohort was 67 ± 18 years; 15,688 (51%) were male.

Most patients had normal albumin levels on admission (20,124, 65%), 29% of patients had hypoalbuminemia, mostly mild (7334

Discussion

Our study focused on patients admitted to medical wards with serum albumin levels obtained within 24 hours of admission and before discharge. The results indicate increased mortality risk in patients with low albumin levels on admission and/or before discharge.

Although our finding of hypoalbuminemia as an independent mortality predictor is not novel, and numerous studies reported that hypoalbuminemia was associated with increased mortality in different patient groups and settings,5, 6, 7, 8, 9,

Acknowledgments

We thank Mrs. Tzipora Shochat for her statistical assistance.

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    Funding: None.

    Conflicts of Interest: None.

    Authorship: AA: Substantial contributions to conception and design, acquisition of data or analysis and interpretation of data, drafting the article or revising it critically for important intellectual content, final approval of the version to be published. HMI: Substantial contributions to conception and design, acquisition of data or analysis and interpretation of data, drafting the article or revising it critically for important intellectual content, final approval of the version to be published. AA: Substantial contributions to conception and design, acquisition of data or analysis and interpretation of data, drafting the article or revising it critically for important intellectual content, final approval of the version to be published. IS: Substantial contributions to conception and design, acquisition of data or analysis and interpretation of data, drafting the article or revising it critically for important intellectual content, final approval of the version to be published.

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