Gastroesophageal reflux disease and asthma: a longitudinal study in UK general practice.
OBJECTIVE
Gastroesophageal reflux disease (GERD) and asthma are common causes for consultation in primary care, but the relationship between the two remains unclear. The aim of our study was to investigate the temporal relationship between first diagnoses of GERD and asthma in general practice.


METHODS
We used the UK General Practice Research Database to identify a cohort of patients with a first diagnosis of GERD (n = 5,653) and another cohort of patients with a first diagnosis of asthma (n = 9,712) during 1996, which we compared with age-matched and sex-matched control cohorts drawn from the general population without either diagnosis. We investigated the incidence of a GERD diagnosis among the asthma patients and control subjects, and the incidence of an asthma diagnosis among the GERD patients and control subjects during a mean follow-up period of 3 years. We calculated the relative risk (RR) of these diagnoses using Cox regression analysis and examined the risk associated with medication use using nested case-control analysis.


RESULTS
The incidence rates of GERD and asthma among the control cohorts were 4.4 and 3.8 per 1,000 person-years, respectively. During the follow-up period, the RR of an incident asthma diagnosis in patients with a new diagnosis of GERD was 1.2 (95% confidence interval [CI], 0.9 to 1.6), while the RR of an incident GERD diagnosis among patients with a new diagnosis of asthma was 1.5 (95% CI, 1.2 to 1.8) after adjustment for age, sex, smoking, prior comorbidity, and number of health-care contacts. This increased risk was mainly seen during the first year of follow-up. The prior use of prescription medications for asthma and GERD had no significant effects on the risk of GERD and asthma diagnosis, respectively.


CONCLUSIONS
Patients with asthma are at a significantly increased risk of developing GERD, mainly during the first year following diagnosis. A nonsignificant increase in the risk of developing asthma was evident among GERD patients. The relationship between GERD and asthma warrants further investigation.
Centro Español de Investigación Farmacoepidemiológica (CEIFE), C/ Almirante 28, 2o, 28004 Madrid, Spain. aruigomez@ceife.es
Ana
A
Ruigómez
Luis Alberto García
LA
Rodríguez
Mari-Ann
MA
Wallander
Saga
S
Johansson
Mike
M
Thomas
David
D
Price
D000293:Adolescent; D000328:Adult; D000368:Aged; D001249:Asthma / Q000150:complications / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D005194:Family Practice; D005260:Female; D005764:Gastroesophageal Reflux / Q000453:epidemiology* / Q000209:etiology; D006801:Humans; D015994:Incidence; D007223:Infant; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D018570:Risk Assessment; D012307:Risk Factors; D006113:United Kingdom / Q000453:epidemiology