Prevalence and patterns of testing for anaemia in primary care in England: a cohort study using an electronic health records database.

BACKGROUND: Despite epidemiological data on anaemia being available on a global scale, the prevalence of anaemia in the UK is not well described. AIM: To describe anaemia prevalence and testing patterns for haemoglobin and other blood parameters. DESIGN AND SETTING: This study was a descriptive population-based cohort study using data drawn from the Clinical Practice Research Datalink Aurum database in 2019. METHOD: Demographic data were extracted for each person who was registered at their current practice during 2019, including linked data on Index of Multiple Deprivation. Anaemia prevalence in 2019 was calculated based on World Health Organization-specified age and gender thresholds for haemoglobin. Anaemia was classified based on mean corpuscular volume and ferritin. People with anaemia were followed up for up to 1 year to investigate longitudinal testing patterns for haemoglobin. RESULTS: The cohort contained 14 million people. Anaemia prevalence in England in 2019 was 4.1% (583 847/14 207 841) (5.1% [363 438/7 121 614] females and 3.1% [220 409/7 086 227] males). Prevalence was higher in people aged >65 years, people of Black and Asian ethnicities, and people living in areas with higher social deprivation. Only half of people with anaemia and a mean corpuscular volume of ≤100 fL had an accompanying ferritin value recorded. About half of people with anaemia had a follow-up haemoglobin test within 1 year, most of which still indicated anaemia. CONCLUSION: Anaemia is prevalent in the UK with large disparities between levels of demographic variables. Investigation and follow-up of anaemia is suboptimal in many patients. Health interventions aimed at improving anaemia investigation and treatment are needed, particularly in the most at-risk groups.