Meta-Analysis Reveals Thyroid Abnormalities in Sickle Cell Disease: A Call for Regular Monitoring

"While T3, T4, and free thyroid hormone levels showed a declining trend, the differences were not statistically significant. Hypothyroidism was detected in 4.9% of SCD patients, while 8.7% had subclinical hypothyroidism, highlighting the importance of routine thyroid function monitoring in this population," the researchers reported in Thyroid Research.

Sickle cell disease, a genetic blood disorder characterized by abnormal hemoglobin, is known to impact multiple organ systems due to chronic anemia, inflammation, and vascular complications. Thyroid function, which plays a critical role in metabolism and overall health, appears to be influenced by the physiological challenges associated with SCD.

Sickle cell disease (SCD), a genetic blood disorder characterized by abnormal hemoglobin, affects multiple organ systems due to chronic anemia, inflammation, and vascular complications. Among its potential impacts, thyroid function—essential for metabolism and overall health—appears to be influenced by the physiological challenges associated with SCD.

In recent years, there has been growing awareness of endocrine dysfunction in both pediatric and adult patients with SCD. Thyroid disorders in this population can have serious clinical consequences, including growth retardation and cognitive impairment. However, data on the prevalence and spectrum of thyroid abnormalities in individuals with SCD remain limited, highlighting the need for further research and regular thyroid function monitoring in this group.

Against the above background, Sagad O. O. Mohamed, Faculty of Medicine, University of Khartoum, Alqasr Avenue, Khartoum, Sudan, and colleagues aimed to offer a comprehensive overview and analysis of thyroid function abnormalities in individuals with sickle cell disease.

For this purpose, the researchers conducted a thorough search across Medline/PubMed, Google Scholar, the World Health Organization Virtual Health Library Regional Portal, and ScienceDirect, adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Pooled prevalence and standardized mean difference (SMD) estimates, were calculated using Comprehensive Meta-Analysis Software version 3.3.

The following were the key findings of the study:

• Nineteen studies met the inclusion criteria and were included in the analyses.

• Serum thyroid-stimulating hormone (TSH) levels were significantly higher in SCD patients than in controls (SMD = 1.184).

• There was a trend toward lower levels of triiodothyronine (T3), thyroxin (T4), free T3, and free T4 in the SCD group, although these differences were not statistically significant:

• T3: SMD = -1.746

• T4: SMD = -1.365

• Free T3: SMD = -0.384

• Free T4: SMD = -1.205

• The pooled prevalence of hypothyroidism and subclinical hypothyroidism among SCD patients was 4.9% and 8.7%, respectively.

This review indicates that patients with sickle cell disease tend to have higher TSH levels compared to the general population, especially in older age groups. Some SCD patients may develop thyroid abnormalities, most commonly subclinical hypothyroidism.

"Although these issues are not widespread, regular monitoring of thyroid function is important to prevent the progression to overt hypothyroidism. Such vigilance can help improve the quality of life and clinical outcomes for these patients. Further research is needed to better understand the mechanisms and factors contributing to thyroid dysfunction in individuals with SCD," the researchers concluded.

Reference:

Mohamed, S.O.O., Ahmed, H., Mohammednoor, M.A.H. et al. Thyroid function abnormalities in individuals with sickle cell disease: a meta-analysis. Thyroid Res 18, 3 (2025). https://doi.org/10.1186/s13044-024-00220-9