Higher sweat chloride levels in patients with asthma: a case-control study.
OBJECTIVE
To screen asthmatic patients by sweat chloride test to identify proportion with Cystic Fibrosis (CF); (Sweat chloride level >60 mmol/L). Also, to compare sweat chloride levels between cases of bronchial asthma and age and sex matched healthy children aged 5 mo-15 y.


METHODS
The present case-control study was conducted in a tertiary care hospital in India. Cases of bronchial asthma, diagnosed by GINA guideline 2008, and age matched healthy controls were included. Case to control ratio was 2:1. Sweat Chloride test was done by Pilocarpine Iontophoresis method.


RESULTS
From April 2010 through May 2012, 216 asthmatics and 112 controls were recruited. Among asthmatics, there was no case of Cystic Fibrosis. Mean sweat chloride levels in asthmatics was 22.39 ± 8.45 mmol/L (inter-quartile range - 15-28 mmol/L) and in controls 19.55 ± 7.04 mmol/L (inter-quartile range - 15-23.5 mmol/L) (p value = 0.048).


CONCLUSIONS
No Cystic Fibrosis case was identified among asthmatics. Mean sweat chloride levels were higher in asthmatics as compared to controls.
Department of Pediatrics, King George's Medical University, Lucknow, Uttar Pradesh, 226003, India, shallya@rediffmail.com.
Shally
S
Awasthi
Pratibha
P
Dixit
Nutan
N
Maurya
D000293:Adolescent; D001249:Asthma / Q000175:diagnosis / Q000453:epidemiology; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D002712:Chlorides / Q000032:analysis*; D003550:Cystic Fibrosis / Q000175:diagnosis* / Q000453:epidemiology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007194:India / Q000453:epidemiology; D008297:Male; D013542:Sweat / Q000737:chemistry*
D002712:Chlorides