Prevalence and patterns of testing for anaemia in primary care in England.

Background Despite epidemiological data on anaemia being available on a global scale, its prevalence in the United Kingdom is not well described. Aim To investigate anaemia prevalence and testing patterns for haemoglobin and other blood parameters. Design and Setting A population-based cohort study using data drawn from the Clinical Practice Research Datalink Aurum database in 2019. Method We extracted demographic data for each person who was registered at their current practice during 2019, including linked data on Index of Multiple Deprivation. We calculated anaemia prevalence in 2019 based on World Health Organization specified age and gender thresholds for haemoglobin. We classified anaemia based on mean corpuscular volume and ferritin. We followed up people with anaemia for up to one year to investigate longitudinal testing patterns for haemoglobin. Results The cohort contained 14 million people. Anaemia prevalence in 2019 was 4.1% (5.1 % females and 3.1% males). Prevalence was higher in people aged >65 years, 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 one-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 these at-risk groups.