Sputum eosinophil counts predict asthma control after discontinuation of inhaled corticosteroids.
BACKGROUND
Although inhaled corticosteroids (ICSs) are effective in preventing deterioration in asthma control, at least half of subjects with mild-to-moderate asthma will remain stable when these agents are discontinued.


OBJECTIVE
We sought to determine whether noninvasive markers of inflammation predict which individuals maintain asthma control after discontinuation of ICSs.


METHODS
We analyzed data obtained from 164 subjects with mild-to-moderate asthma who participated in a 16-week trial comparing the effects of continued ICS use with the effects of a switch to salmeterol or placebo.


RESULTS
In comparison with continued ICS use, a switch to salmeterol or placebo was associated with increased rates of asthma deterioration over 16 weeks (9.3% vs 24.1% and 37.5%, respectively; P = .04 and P < .001, respectively). We found that neither exhaled nitric oxide nor methacholine PC 20 , when measured at randomization or 2 weeks after randomization, were significant predictors of subsequent asthma control in subjects who discontinued ICSs. However, both induced sputum eosinophil counts measured 2 weeks after a switch from ICS to placebo and changes in sputum eosinophil counts from before cessation of ICSs to after a switch to placebo predicted subsequent asthma deterioration (area under the receiver-operating characteristic curve, 0.771 [ P < .001] and 0.825 [ P < .001], respectively).


CONCLUSIONS
On the basis of a model treatment strategy, we estimate that allocating subjects to ICS therapy on the basis of changes in sputum eosinophil counts after a trial discontinuation could allow 48% of subjects with mild-to-moderate asthma to discontinue ICS therapy without an increased risk of asthma deterioration over a period of at least 14 weeks.
Deykin
Aaron
A
Brigham and Women's Hospital and Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA. adeykin@partners.org
Lazarus
Stephen C
SC
Fahy
John V
JV
Wechsler
Michael E
ME
Boushey
Homer A
HA
Chinchilli
Vernon M
VM
Craig
Timothy J
TJ
Dimango
Emily
E
Kraft
Monica
M
Leone
Frank
F
Lemanske
Robert F
RF
Martin
Richard J
RJ
Pesola
Gene R
GR
Peters
Stephen P
SP
Sorkness
Christine A
CA
Szefler
Stanley J
SJ
Israel
Elliot
E
D000280:Administration, Inhalation; D000305:Adrenal Cortex Hormones / Q000008:administration & dosage*; D000328:Adult; D000420:Albuterol / Q000008:administration & dosage / Q000031:analogs & derivatives*; D001249:Asthma / Q000188:drug therapy* / Q000276:immunology / Q000503:physiopathology; D015415:Biomarkers / Q000032:analysis*; D001993:Bronchodilator Agents / Q000008:administration & dosage; D002452:Cell Count; D004804:Eosinophils / Q000166:cytology / Q000187:drug effects*; D005260:Female; D006801:Humans; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism; D012372:ROC Curve; D012129:Respiratory Function Tests; D012189:Retrospective Studies; D000068299:Salmeterol Xinafoate; D013183:Sputum / Q000166:cytology*
D000305:Adrenal Cortex Hormones; D015415:Biomarkers; D001993:Bronchodilator Agents; D009569:Nitric Oxide; D000068299:Salmeterol Xinafoate; D000420:Albuterol