Effect of increased body mass index on asthma risk, impairment and response to asthma controller therapy in African Americans.
OBJECTIVE
To explore whether obesity alters the risk, impairment and response to treatment in African Americans with asthma.


METHODS
The data used for this secondary analysis are from a 1-year study in African American subjects comparing fluticasone propionate/salmeterol 100/50 microg combination (FSC) and fluticasone propionate 100 microg (FP). Subjects were retrospectively stratified by body mass index (BMI) <20 [underweight], 20-24.9 [normal weight], 25-29.9 [overweight], 30-34.9 [obese I], 35-39.9 [obese II], and >or=40 [obese III] kg/m(2). Outcomes studied included impairment domains: FEV(1), morning and evening peak expiratory flow (AM and PM PEF), daily albuterol use, daily symptom scores and future risk domain: exacerbations.


BACKGROUND
www.clinicaltrials.gov; NCT00102765.


RESULTS
There were 475 subjects evenly distributed between FSC and FP by baseline parameters. There were 207 subjects with a BMI >or=30, including 70 subjects with a BMI >or=40. Baseline BMI >or=40 was associated with numerically lower baseline AM and PM PEF. There was an attenuation of response to both treatments for only PM PEF (p < 0.05). By contrast, subjects with lower degrees of obesity or overweight did not differ from those with normal weight. The total population exacerbation rate was 2-fold greater in obese III subjects (39%) compared with subjects in other BMI categories (16-21%) (p < 0.05). A potential study limitation is the retrospective analysis of existing data.


CONCLUSIONS
Response to treatment was attenuated for PM PEF for subjects with BMI >or=40 and was also associated with an increased rate of asthma exacerbations.
Camargo
Carlos A
CA
Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
Sutherland
E Rand
ER
Bailey
William
W
Castro
Mario
M
Yancey
Steven W
SW
Emmett
Amanda H
AH
Stempel
David A
DA
D000293:Adolescent; D000328:Adult; D001741:Black or African American / Q000706:statistics & numerical data; D000368:Aged; D018927:Anti-Asthmatic Agents / Q000627:therapeutic use*; D001249:Asthma / Q000175:diagnosis / Q000188:drug therapy* / Q000208:ethnology / Q000209:etiology*; D015992:Body Mass Index; D002648:Child; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015337:Multicenter Studies as Topic; D016032:Randomized Controlled Trials as Topic; D012189:Retrospective Studies; D012307:Risk Factors; D016896:Treatment Outcome; D055815:Young Adult
D018927:Anti-Asthmatic Agents