Insomnia symptom prevalence in England: A comparison of self-reported data and primary care records in the UK Biobank

PurposeWe aimed to use a large dataset to compare self-reported and primary care measures of insomnia symptom prevalence in England and establish whether they identify participants with similar characteristics. MethodsWe analysed data from 163,748 UK Biobank participants in England (aged 38-71 at baseline) with linked primary care electronic health records. We compared the percentage of those self-reporting usually having insomnia symptoms at UK Biobank baseline assessment (2006-2010) to those with a Read code for insomnia symptoms in their primary care records prior to baseline. We stratified prevalence in both groups by sociodemographic, lifestyle, sleep and health characteristics. ResultsWe found that 29% of the sample self-reported having insomnia symptoms, whilst only 6% had a Read code for insomnia symptoms in their primary care records. Only 10% of self-reported cases had an insomnia symptom Read code, whilst 49% of primary care cases self-reported having insomnia symptoms. In both primary care and self-reported data, prevalence of insomnia symptom cases was highest in females, older participants and those with the lowest household incomes. However, whilst snorers and risk takers were more likely to be a primary care case, they were less likely to self-report insomnia symptoms than non-snorers and non-risk takers. ConclusionsOnly a small proportion of individuals experiencing insomnia symptoms present to primary care. However, the sociodemographic characteristics of people attending primary care with insomnia were consistent with those with self-reported insomnia, thus primary care records are a valuable data source for studying risk factors for insomnia. Key PointsO_LIAround a third of the general population is thought to suffer from insomnia symptoms, but estimates are based on small samples and rely on people self-reporting their symptoms. C_LIO_LIElectronic health records (EHRs) offer a more objective means of measuring insomnia prevalence, but small-scale studies suggest they only capture a small proportion of insomnia cases. It is therefore unclear how useful EHRs are in measuring the prevalence of insomnia. C_LIO_LIIn a sample of over 160,000 UK Biobank participants in England we found that 29% of participants self-reported having insomnia symptoms, whilst only 6% had a Read code for insomnia symptoms in their primary care records. C_LIO_LICharacteristics of people attending primary care with insomnia symptoms are similar to those self-reporting insomnia symptoms, suggesting EHRs offer a valuable data source for studying risk factors for insomnia. C_LI Plain Language SummaryAround a third of the general population is thought to suffer from insomnia symptoms, but estimates are based on the responses of a small number of people and rely on them reporting their own symptoms. Peoples medical records offer a more objective way of finding out how many people have insomnia, but only capture people who go to their doctor for help. In this study we compared 160,000 peoples answers to a question on insomnia symptoms to their primary care records. We found that 29% of people reported insomnia symptoms, whereas only 6% had insomnia symptoms recorded in their medical records. However, the characteristics of those reporting insomnia and those with insomnia in their medical records were similar. This means that although medical records only capture a small proportion of those suffering from insomnia, they do still provide useful information for researchers studying risk factors for insomnia.