Genotypic Variations in Exercise-Induced Hemoglobin Oxygen Desaturation in Sickle Cell Disease: The Role of Hemoglobin Levels

Abstract

Background: Sickle cell disease (SCD) presents abnormal hemoglobin S (HbS) and frequent vaso-occlusive crises. Previous studies reveal exercise intolerance in SCD patients. However, the role of exercise-induced hemoglobin oxygen desaturation (EIHOD) and its predictors remains unclear. This study investigates EIHOD in adult SCD patients, focusing on potential predictors, aligning with the hypothesis that EIHOD is prevalent and varies across genotypes, with hemoglobin as a predictor. Methods: A cross-sectional study was conducted on adult patients with HbSS and HbSC genotypes in a steady state at the Korle-Bu Teaching Hospital, Ghana. Clinical, hematological, and haemolytic markers were assessed. Lung function was evaluated through spirometry, and a six-minute walk test (6MWT) was performed to assess EIHOD. Logistic regression was used to identify predictors of EIHOD. We hypothesis that, EIHOD is common in SCD, varying across genotypes, with hemoglobin predicting its occurrence. Results: The prevalence of EIHOD was 41% in HbSS patients and 36.1% in HbSC patients. No significant differences were observed in age, white blood cell count, platelet count, hemolytic markers, hemoglobin levels, or lung function parameters between SCD patients with and without EIHOD. In the logistic regression model, none of the variables predicted EIHOD in HbSS patients. In HbSC patients, reduced hemoglobin was the only predictor of EIHOD (OR=0.551; 95% CI=0.315-0.964; p-value= 0.037). Discussion: The study highlights a high prevalence of EIHOD within the HbSS genotype, emphasizing the importance of hemoglobin levels as a predictor of EIHOD in SCD. Contrarily, hemolytic markers and lung function were not predictors of EIHOD across either genotype. These results suggest the potentially heightened significance of EIHOD-related complications in patients with the HbSS genotype. Conclusion: EIHOD is common in SCD, more so in HbSS. Reduced hemoglobin predicts EIHOD in HbSC. Lung function and hemolytic markers don't. Understanding the impact of EIHOD in SCD may guide interventions to improve exercise tolerance and reduce complications in this population. No Funding. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.