Iron is needed to carry oxygen in the blood. This process uses haemoglobin (Hb) in red blood cells. Iron is also needed for other processes to maintain body functions. Iron deficiency (ID) happens when there is not enough iron in the body for normal daily living. Iron deficiency anaemia (IDA) is where ID leads to fewer healthy red blood cells being available to carry oxygen in the blood. These conditions can lead to serious health problems and affect quality of life. Common symptoms of ID or IDA include pale skin, tiredness, breathlessness, irregular heartbeat and headaches.
The most common causes of ID and IDA are blood loss, decreased iron absorption and poor diet. Both ID and IDA can happen as a result of other health conditions, including inflammatory bowel disease (IBD) and stomach ulcers; chronic kidney disease (CKD); chronic heart failure (CHF); and cancer.
ID and IDA can be treated with iron therapy, administered by oral tablets or an injection of iron. Blood transfusions are sometimes used but this is rare. In England and the rest of the UK, little is known about treatment pathways for ID and IDA, such as who receives different types of iron therapy or how long patients stay on each type of treatment. There is also limited information available describing how patients with ID or IDA access healthcare services and the costs related to the services they require. Therefore, this study will investigate how ID and IDA are managed in England by describing patients and their treatments.
Patients with iron deficiency (ID) or iron deficiency anaemia (IDA) require iron therapy to normalise haemoglobin (Hb) levels and replenish body iron stores. These conditions often occur alongside, and due to, comorbid conditions, including inflammatory bowel disease (IBD), chronic kidney disease (CKD) and cancer. Little is known about the nature and extent of ID and IDA management in England.
This retrospective cohort study will investigate the profiles of ID/IDA patients, their iron therapy treatments and outcomes in England. The study will describe treatment pathways for ID and IDA in primary care and secondary care, patients demographic and clinical characteristics, their haematological and biochemical treatment outcomes and the economic (healthcare resource) impact of treatment.
Primary care data will be extracted from Clinical Practice Research Datalink (CPRD) for patients aged ?18 years on the date of first ever recorded diagnosis of ID or IDA or date of first ever iron therapy prescription (index event between 01 July 2007 and 30 June 2018). The study period will be from 01 July 2007 to 30 June 2019, with a lookback period of up to five years from the index date to measure comorbidities and clinical history.
Patient characteristics will be measured at baseline. Clinical pathways will be described using CPRD data linked to inpatient, outpatient and Accident & Emergency Hospital Episode Statistics (HES) data. Patterns in iron treatment prescribing will be analysed. The economic (healthcare resource utilisation) impact of ID and IDA management, such as hospitalisations, and associated costs will be quantified .
Descriptive analyses using chi-square tests and t-tests and multivariable analyses using logistic or linear regression, and Kaplan-Meier, where appropriate, will be undertaken. Sensitivity analyses will investigate temporal patterns in iron treatment prescribing and the impact of fluctuating patient numbers over the study period. Exploratory analyses, if data quality allows, will investigate outcomes related to haematological and biochemical markers.
Clinical and economic outcomes will be measured in this study. These outcomes are further described in section N., and will include the following:
Clinical outcomes
Time from ID or IDA diagnosis to first iron therapy, where index event is diagnosis not prescription
Number of lines of iron therapy
Number of IV iron infusions or injections
Number of intramuscular iron injections
Length of time on oral iron therapy
Change in Hb concentration, and other haematological and biochemical markers, over time
Duration of Hb normalisation* while on treatment
Duration of Hb normalisation* not on treatment
Treatment change
Treatment adherence
Treatment-related side effects
Treatments related to iron therapy or anaemia
*Normalisation defined as Hb?12 g/dL in (non-pregnant) female patients and ?13 g/dL in male patients(1), but other definitions may apply to patient subgroups of interest in this study
Economic (healthcare resource) outcomes
Iron therapy prescribing
Primary care attendances
Referrals to secondary care clinic
Outpatient appointments
Accident and Emergency department attendances
Hospital admissions
Length of hospital stay
Blood tests and other investigations
Other outcomes
Reason for lost to follow up, where recorded
Phil McEwan - Chief Investigator - Health Economics & Outcomes Research Ltd ( HEOR Ltd )
Oksana Kirichek - Corresponding Applicant - Health Economics & Outcomes Research Ltd ( HEOR Ltd )
- Collaborator -
Daniel Murphy - Collaborator - Norgine
Matthew Turner - Collaborator - Health Economics & Outcomes Research Ltd ( HEOR Ltd )
Nia Jenkins - Collaborator - Health Economics & Outcomes Research Ltd ( HEOR Ltd )
William Burch - Collaborator - Norgine
Andrew Holgate - Collaborator - Norgine
Michael Hurst - Collaborator - Health Economics & Outcomes Research Ltd ( HEOR Ltd )
Sangeeta Sharma - Collaborator - Norgine
Stephen McKenna - Collaborator - Health Economics & Outcomes Research Ltd ( HEOR Ltd )
HES Accident and Emergency;HES Admitted Patient Care;HES Outpatient;Practice Level Index of Multiple Deprivation