The Effects of Hydroxyurea Therapy on the Six-Minute Walk Distance in Patients with Adult Sickle Cell Anemia: An Echocardiographic Study
Received 1 February 2019
Accepted for publication 16 October 2019
Published 27 December 2019 Volume 2019:10 Pages 443—452
Checked for plagiarism Yes
Review by Single-blind
Peer reviewer comments 2
Editor who approved publication: Dr Martin H Bluth
Taysir Garadah,1,2 Fatema Mandeel,2 Ahmed Jaradat,1 Khalid Bin Thani1,2
1Medical Department, College of Medicine and Medical Sciences, Arabian Gulf University, Manama, Kingdom of Bahrain; 2Medical Department, Cardiac Unit, Salmanyia Medical Complex, Manama, Kingdom of Bahrain
Correspondence: Taysir Garadah
Medical Department, College of Medicine and Medical Sciences, Arabian Gulf University, P.O. Box 26671, Manama, Kingdom of Bahrain
Background: The impact of hydroxyurea (HU) medication as treatment of choice has not been evaluated in adult sickle cell anemia (SCA) patients in terms of the 6-min walk distance (6 MWD).
Aim: The aim of the study was evaluating the effects of HU on the 6 MWD, serum brain natriuretic peptide (NT-pro BNP) level, and pulmonary hypertension (PH) measured by tricuspid regurgitation velocity (TRV).
Methods: In this cross-sectional, prospective study, 110 patients with homozygous SCA were studied and compared with age- and gender-matched healthy controls. Every patient was investigated via pulsed and tissue Doppler echo evaluation, 6-min walk test (6 MWT), and blood level for the level of NT-pro-BNP hormone. Data were compared in patients with (n = 59; group 1, G1) and without (n = 51; group 2, G2) HU medication. Pearson correlation analysis was applied and clinical follow-up for the frequency of acute chest syndrome (ACS). Analysis of variance (ANOVA) multivariate statistical analysis was applied between groups.
Results: In the study, 110 patients with SCA were studied and compared with 110 control patients. Patients in G1 compared with G2 had a longer 6 MWD (491 ± 64.4 m vs 428.6 ± 54.3 m, p < 0.005), higher HbF% (21 ± 2.5% vs 8 ± 1.8%, p < 0.005), and lower NT-pro-BNP level (314.1 ± 27.5 pmol/L vs 407 ± 18.9 pmol/L, p = 0.05). The mean TRV values were 2.8 ± 0.5 m/s in G1 versus 3.4 ± 0.4 m/s in G2, p < 0.005, and 1.5 ± 0.7 m/s in the control group. The high probability of PH based on a TRV > 3.4 m/s was 10.1% in G1 versus 17.6% in G2 and 3.6% in the control. There were weak positive correlations between NT-pro-BNP and TRV (r = 0.264; p = 0.005) and HbF% and 6 MWD (r = 0.452; p = 0.001). After 12 months of follow-up, frequency of acute chest syndrome (ACS) was twice as high in G2, at 32 patients, versus 16 in G1.
Conclusion: Patients with SCA on HU medication compared with no HU had significantly longer 6 MWD, lower level of NT-pro-BNP, higher HbF% level. After 1-year follow-up HU patients had less frequency of ACS. There were significant positive correlations between the level of NT-pro BNP level and TRV in m/s on echo.
Keywords: sickle cell anemia, 6-min walk test, hydroxyurea, NT-pro BNP, echocardiography, diastolic dysfunction, pulmonary hypertension
This work is published and licensed by Dove Medical Press Limited. The full terms of this license are available at https://www.dovepress.com/terms.php and incorporate the Creative Commons Attribution - Non Commercial (unported, v3.0) License. By accessing the work you hereby accept the Terms. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed. For permission for commercial use of this work, please see paragraphs 4.2 and 5 of our Terms.Download Article [PDF] View Full Text [HTML][Machine readable]