Measuring Health-Related Quality of Life in Sickle Cell Disease Patients Undergoing Automated Red Blood Cell Exchange in the USA, France and the UK

Background

Sickle cell disease (SCD) is a group of disorders that affects hemoglobin, the molecule in red blood cells that delivers oxygen to cells throughout the body. People with this disorder have atypical hemoglobin molecules called hemoglobin S, which can distort red blood cells into a sickle, or crescent, shape. Additionally, affected red blood cells have a high likelihood of stacking up and causing blockages in the small blood vessels. Both mechanisms of disease may cause damage to organs requiring oxygen, which causes pain and may be deadly. SCD and its complications reduce life expectancy and the nature of its complications and treatments may cause reduced quality of life. Although a rare disease, SCD may cause significant costs to healthcare and society. Depending on the indication, either hydroxyurea or chronic RBC transfusion is employed to treat SCD patients. RBC transfusion, simple or exchange, is first-line treatment for primary and secondary prevention of stroke. When the study was performed, no published research had been completed that compared patient outcomes in terms of Health-Related Quality of Life (HRQoL) for patients treated with automated red blood cell exchange versus simple transfusion.

Objectives

There are multiple objectives covered within the scope of this study:

• To quantify HRQoL as experienced by SCD patients in aRBCx versus simple transfusion.

• To determine the drivers of HRQoL amongst SCD patients

• To assess whether physicians and patients have a similar view on the impact of aRBCx on HRQoL amongst SCD patients.

Methodology

A cross-sectional study was performed amongst 40 SCD patients, 20 from the USA, 10 from France and 10 from the UK as well as amongst 40 SCD treating physicians with experience in both simple transfusion as well as aRBCX. The physicians had the same regional distribution as the patients.

Results

SCD patients undergoing aRBCX reported an HRQoL that was 25% higher compared to the period where they were treated with simple transfusion (0.70 vs. 0.55; p<0.01). The main drivers of HRQoL identified were (correlation efficient): pain reduction (0.57), improved social live (0.49), autonomy in terms of all day living activities and being independent from others (0.56), feeling energetic and physical functioning (0.57) and lastly emotional worry and mental health (0.56), all with p-values < 0.01. Together these variables explain 39% of the HRQoL experienced by SCD patients (R² = 0.39, p < 0.01). 80% of the patients preferred aRBCx over simple transfusion. 87% of the participating physicians believed that switching patients from simple transfusion to automated red blood cell exchange (aRBCX) positively affected the SCD patients' quality of life. Physicians identified the following factors being responsible for the improved HRQoL in patients on aRBCX. Those with an average score of 5.5 or greater on a 7-point scale were: less iron overload, RBCX effectiveness, reduced acute complications, reduced chronic complications, and superior mechanism of action during acute situations.

Conclusion

Sickle cell disease patients that require chronic blood transfusion experience better health-related quality of life when they are treated with automated red blood cell exchange versus simple transfusion. This observation is supported by the opinion of their treating physicians.