Looking at the relationship between hemoglobin concentration and prevalent mobility difficulty in older women. Should the criteria currently used to define anemia in older people be reevaluated?
OBJECTIVE
The World Health Organization (WHO) and other currently used criteria for defining anemia in older women are mainly based on statistical distribution considerations. To explore their clinical appropriateness, we evaluated the relationship between hemoglobin (Hb) concentration, prevalent mobility difficulty, and the Summary Performance Score (SPS).


METHODS
Cross-sectional study.


METHODS
Two population-based studies, the Women's Health and Aging Studies I and II, Baltimore, Maryland.


METHODS
Six hundred thirty-three community-dwelling women aged 70 to 80 with Hb levels obtained within 90 days from baseline assessment.


METHODS
Mobility difficulty (self-reported difficulty walking one-quarter of a mile or climbing 10 steps (primary outcome)). SPS, a performance-based summary measure of lower extremity function that combines the results of walking, chair stands, and balance tests (secondary outcome).


RESULTS
Mobility difficulty prevalence was not constant within the WHO "normal" Hb range (12.0-16.0 g/dL). For example, a Hb of 13.5 g/dL was associated with a significantly lower mobility difficulty prevalence than a Hb of 12.0 g/dL (OR=0.68, 95% CI=0.47-0.93), even after adjustment for chronic diseases and other relevant health indicators. A consistent trend of improvement in performance-based scores with increasing Hb categories less than 12.0 g/dL, 12.0 to 13.0g/dL, and 13.0-14.0 g/dL was observed.


CONCLUSIONS
Our findings raise two hypotheses: (1) Hb currently perceived as "mildly-low" and even "low-normal" might have an independent, adverse effect on mobility function, and (2) Hb of 12.0 g/dL might be a suboptimal criterion for defining anemia in older women. Formal testing of these hypotheses might prove relevant for anemia- and mobility disability-related clinical decision-making.
Chaves
Paulo H M
PH
Division of Internal Medicine, Department of Medicine, School of Public Health, The Johns Hopkins University, Baltimore, Maryland, USA. pchaves@jhsph.edu
Ashar
Bimal
B
Guralnik
Jack M
JM
Fried
Linda P
LP
D000368:Aged; D000369:Aged, 80 and over; D000740:Anemia / Q000097:blood*; D003430:Cross-Sectional Studies; D005260:Female; D016330:Frail Elderly; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D016013:Likelihood Functions; D009069:Movement Disorders / Q000453:epidemiology*; D015995:Prevalence; D012044:Regression Analysis; D018709:Statistics, Nonparametric; D014481:United States / Q000453:epidemiology
D006454:Hemoglobins