This study will investigate the recording of the diagnosis of asthma in the primary care medical records database called Clinical Practice Research Datalink (CPRD GOLD). This will be done by the collection of information provided by general practitioners through a questionnaire. This information will then be examined by two independent expert physicians and compared to the recording of asthma within the CPRD database. The diagnosis of asthma is mostly based on a characteristic pattern of symptoms and the absence of another diagnosis. Because of this, asthma is not as well defined as some other diseases, and the clinical diagnosis might be less accurate. The study to be undertaken could help establish the best strategy to identify individuals with asthma within the CPRD. This would inform the definitions and patient selection for further observational and potentially pragmatic intervention studies in CPRD and other primary care data sources.
The overall aim of this study is to determine the positive predictive value (PPV) of an asthma diagnostic code within the CPRD GOLD, i.e., a proportion of true positives among those assumed to have been diagnosed with asthma. In order to achieve this we will construct a retrospective cohort of asthma patients and compare database information (CPRD GOLD and the Multiple Deprivation Index) with information gathered by a questionnaire filled in by general practitioners and review of any supporting information sent. A review of these questionnaires by two independent expert physicians will be considered as the gold standard to assess the PPV of an asthma recording using specific algorithms in CPRD GOLD.
Jennifer Quint - Chief Investigator - Imperial College London
Francis Nissen - Corresponding Applicant - Roche
Daniel Morales - Collaborator - University of Dundee
Hana Mullerova - Collaborator - AstraZeneca Ltd - UK Headquarters
Ian Douglas - Collaborator - London School of Hygiene & Tropical Medicine ( LSHTM )
Liam Smeeth - Collaborator - London School of Hygiene & Tropical Medicine ( LSHTM )
Neil Pearce - Collaborator - London School of Hygiene & Tropical Medicine ( LSHTM )
Patient Level Index of Multiple Deprivation;Practice Level Index of Multiple Deprivation