Angiotensin converting enzyme inhibitors (ACEI) and angiotensin receptor blockers (ARB) are drugs that are commonly used to treat high blood pressure and heart failure. Haemoglobin is the molecule in red blood cells that carries oxygen from the lungs to the body. When there is not enough haemoglobin in the blood (anaemia) people experience symptoms like fatigue, weakness and shortness of breath. Anaemia can also worsen heart and kidney disease, and is associated with increased risk of death. There is some evidence to suggest that ACEI/ARB drugs cause anaemia. Our study therefore aims to investigate the effect of starting ACEI/ARB drugs on haemoglobin levels, using a comparison drug (calcium channel blockers, which are alternative drugs used to treat the same types of conditions as ACEI/ARBs). We will also investigate whether the effect of ACEI/ARB drugs on anaemia is influenced by either: the patientÂ’s haemoglobin level prior to starting the drug, or their kidney function (the kidneys produce a hormone that controls red blood cell production). This information would help improve prescribing guidelines for these drugs, offer insight into their risks and benefits, and help identify those needing careful haemoglobin monitoring when starting on ACEI/ARBs.
We aim to investigate the association between ACEI/ARBs and reduction in haemoglobin. We will identify a cohort of new-users of ACEI/ARBs and calcium channel blockers (CCB) with haemoglobin levels recorded both before (up to one year) and after (up to six months) drug initiation. We will calculate and compare mean haemoglobin change following ACEI/ARB or CCB initiation. We will use logistic regression to identify risk factors associated with a fall in haemoglobin after drug initiation. Risk factors considered will include: age, sex, ACEI/ARB or CCB use, chronic comorbidities (diabetes mellitus, cardiac failure, chronic kidney disease, hypertension, ischaemic heart disease, myeloproliferative syndromes, and chronic lung disease), pre-initiation haemoglobin level, past history of gastrointestinal bleeding, medications and lifestyle factors (smoking, alcohol intake, and body mass index). We will also: (1) Investigate whether baseline haemoglobin level and chronic kidney disease modify the effect of ACEI/ARBs on haemoglobin; (2) Compare change in haemoglobin between new users of ACEIs and ARBs by comparing mean change in haemoglobin and calculating the odds of a fall in haemoglobin in each group; and (3) Compare the proportion of ACEI, ARB and CCB users with records indicating post-initiation bone marrow suppression.
Laurie Tomlinson - Chief Investigator - London School of Hygiene & Tropical Medicine ( LSHTM )
Kathryn Mansfield - Corresponding Applicant - London School of Hygiene & Tropical Medicine ( LSHTM )
Dorothea Nitsch - Collaborator - London School of Hygiene & Tropical Medicine ( LSHTM )
George Greenhall - Collaborator - London School of Hygiene & Tropical Medicine ( LSHTM )
Kathryn Mansfield - Collaborator - London School of Hygiene & Tropical Medicine ( LSHTM )
Liam Smeeth - Collaborator - London School of Hygiene & Tropical Medicine ( LSHTM )
Masao Iwagami - Collaborator - University of Tsukuba
Rosalynd Johnston - Collaborator - NHS
HES Admitted Patient Care;HES Outpatient