Serum interleukin-6 and hemoglobin as physiological correlates in the geriatric syndrome of frailty: a pilot study.
OBJECTIVE
To determine specific physiological correlates of the geriatric syndrome of frailty that warrant further investigation.


METHODS
Population-based case-control study.


METHODS
General Clinical Research Center at Johns Hopkins Bayview Medical Center.


METHODS
Community-dwelling adults aged 74 and older from Baltimore, Maryland.


METHODS
Frailty status was determined using a recently validated screening tool that consists of weight loss, fatigue, low levels of physical activity, and measurements of grip strength and walking speed. Serum interleukin-6 (IL-6) was measured using enzyme-linked immunosorbent assay, and standard complete blood count was performed using a Coulter counter.


RESULTS
Eleven frail and 19 nonfrail subjects with mean age +/- standard deviation of 84.9 +/- 6.7 vs 81.3 +/- 4.1 years, respectively, completed the study. The frail subjects had significantly higher serum IL-6 levels and significantly lower hemoglobin and hematocrit than the nonfrail subjects (4.4 +/-2.9 vs 2.8 +/- 1.6 pg/mL, 12.1 +/- 1.1 vs 13.9 +/- 1.0 g/dL, and 35.8% +/- 3.1% vs 40.6% +/- 2.8%, respectively). No significant difference was observed in mean corpuscular volume, red blood cell distribution width, or white blood cell and platelet counts between the frail and nonfrail groups. Furthermore, there was an inverse correlation between serum IL-6 level and hemoglobin (Pearson's correlation coefficient: -0.46) and hematocrit (-0.48) in the frail group but not in the nonfrail group.


CONCLUSIONS
These results suggest that frail subjects have evidence of inflammation and lower hemoglobin and hematocrit levels. This subclinical anemia is normocytic and is hence unlikely due to myelosuppression or iron deficiency and is potentially related to the increased chronic inflammatory state marked by serum IL-6 elevation. Further studies are indicated to better characterize the immune and hematological changes that underlie frailty.
Division of Geriatric Medicine and Gerontology, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA.
Sean
S
Leng
Paulo
P
Chaves
Kathleen
K
Koenig
Jeremy
J
Walston
D000368:Aged; D016022:Case-Control Studies; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D016330:Frail Elderly; D015577:Geriatric Assessment; D006400:Hematocrit; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D015850:Interleukin-6 / Q000097:blood*; D008297:Male; D010865:Pilot Projects; D013577:Syndrome
D006454:Hemoglobins; D015850:Interleukin-6