Body mass, fat-free body mass, and prognosis in patients with chronic obstructive pulmonary disease from a random population sample: findings from the Copenhagen City Heart Study.
BACKGROUND
Low body mass index (BMI) is a marker of poor prognosis in chronic obstructive pulmonary disease (COPD). In the general population, the harmful effect of low BMI is due to the deleterious effects of a low fat-free mass index (FFMI; fat-free mass/weight(2)).


OBJECTIVE
We explored distribution of low FFMI and its association with prognosis in a population-based cohort of patients with COPD.


METHODS
We used data on 1,898 patients with COPD identified in a population-based epidemiologic study in Copenhagen. FFM was measured using bioelectrical impedance analysis. Patients were followed up for a mean of 7 yr and the association between BMI and FFMI and mortality was examined taking age, sex, smoking, and lung function into account.


RESULTS
The mean FFMI was 16.0 kg/m(2) for women and 18.7 kg/m(2) for men. Among subjects with normal BMI, 26.1% had an FFMI lower than the lowest 10th percentile of the general population. BMI and FFMI were significant predictors of mortality, independent of relevant covariates. Being in the lowest 10th percentile of the general population for FFMI was associated with a hazard ratio of 1.5 (95% confidence interval, 1.2-1.8) for overall mortality and 2.4 (1.4-4.0) for COPD-related mortality. FFMI was also a predictor of overall mortality when analyses were restricted to subjects with normal BMI.


CONCLUSIONS
FFMI provides information in addition to BMI and assessment of FFM should be considered in the routine assessment of COPD.
Vestbo
Jørgen
J
Department of Cardiology and Respiratory Medicine, 253 Hvidovre Hospital, Kettegaard Alle 30, DK-2650 Hvidovre, Denmark. joergen.vestbo@hh.hosp.dk
Prescott
Eva
E
Almdal
Thomas
T
Dahl
Morten
M
Nordestgaard
Børge G
BG
Andersen
Teis
T
Sørensen
Thorkild I A
TI
Lange
Peter
P
D050154:Adiposity; D000368:Aged; D015992:Body Mass Index; D001835:Body Weight; D015331:Cohort Studies; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology*