Validating childhood asthma in an epidemiological study using linked electronic patient records.
OBJECTIVE
To investigate the performance of parent-reported data in identifying physician-confirmed asthma.


METHODS
Validation study using linkage between the Avon Longitudinal Study of Parents and Children (ALSPAC) and electronic patient records held within the General Practice Research Database (GPRD).


METHODS
Participants were those eligible to participate in ALSPAC who also had a record in the GPRD; this included 765 individuals, just under 4% of ALSPAC-eligible participants. The analysis was based on 141 participants with complete parent-reported asthma data.


METHODS
The main GPRD outcome measure was whether a child had a diagnosis of asthma before they were nine. Parent-reported measures were doctor diagnosis of asthma (before mean age 7.5 years), various outcomes based on wheezing and breathlessness recorded longitudinally between 6 months and 8.5 years. Secondary outcomes were bronchial hyper-responsiveness (BHR), forced expiratory volume in 1 s/forced vital capacity ratio and skin prick test responses.


RESULTS
Among the 141 participants with complete parent-reported data, 26 (18%) had an asthma diagnosis before age nine. Using general practitioner (GP)-recorded asthma as the gold standard, the question 'Has a doctor ever diagnosed your child with asthma?' was both sensitive (88.5%) and specific (95.7%). 'Ever wheezed' had the highest sensitivity (100%) but low specificity (60%). More specific definitions were obtained by restricting to those who had wheezed on more than one occasion, experienced frequent wheeze and/or wheezed after the age of 3, but these measures had low sensitivities. BHR only identified 50% of those with a GP-recorded diagnosis.


CONCLUSIONS
Parental reports of a doctor's diagnosis agree well with a GP-recorded diagnosis. High specificity for asthma can be achieved by using detailed wheezing questions, although these definitions are likely to exclude mild cases of asthma. Our study shows that linkage between observational studies and electronic patient records has the potential to enhance epidemiological research.
School of Social and Community Medicine, University of Bristol, Bristol, UK.
Rosaleen P
RP
Cornish
John
J
Henderson
Andrew W
AW
Boyd
Raquel
R
Granell
Tjeerd
T
Van Staa
John
J
Macleod
D001249:Asthma / Q000175:diagnosis* / Q000453:epidemiology; D002648:Child; D019992:Databases as Topic; D057286:Electronic Health Records; D058006:General Practice; D006801:Humans; D015994:Incidence; D008137:Longitudinal Studies; D008498:Medical Record Linkage; D010290:Parents; D012135:Respiratory Sounds / Q000209:etiology; D057566:Self Report
Epidemiology; Primary Care