Reduced Frequency of Bone Pain Crises in Patients with Sickle Cell Disease Given an Angiotensin-converting Enzyme Inhibitor

Objective: To determine if sickle cell disease (SCD) bone pain crisis is mitigated by use of an angiotensin-converting enzyme inhibitor (ACEI), following a case report of ACEIs preventing bone pain crisis. Methods: Patients with SCD who attended the Haematology Clinic at Jos University Teaching Hospital, Nigeria, were assessed with a questionnaire, given 2.5 mg of ramipril and followed up monthly for three months. Frequencies of bone pain crises in the month preceding enrolment and three months following treatment as well as the cardiovascular status were evaluated. Results: Thirty-five patients with complete data were reported. Blood pressure remained stable, and cumulative frequency of bone pain crises fell. The relative risk reduction for bone pain was 56.2% at one month, 63.0% at two months and 13.0% at three months. Conclusion: Vaso-occlussion-induced hypoxia, triggering bone pain crises, produces angiotensin II from angiotensin and worsens vasoconstriction. Angiotensin-converting enzyme inhibitors block this process, reducing severity or preventing bone pain crises. With these observations and a stable blood pressure profile, we recommend wider use of ACEIs in patients with SCD to cut down on the need of opioid use with attendant addiction risk, as a way of improving their quality of life.