Pulmonary Function Tests in Kids with SCD May Screen for Chronic Lung Disease, Study Suggests

A Brazilian study showed that nearly 25 percent of children and adolescents with sickle cell disease (SCD) have pulmonary function abnormalities, and suggests that childhood testing may be able to screen for chronic lung disease in these patients.

Findings of the study, “Pulmonary function in children and adolescents with sickle cell disease: have we paid proper attention to this problem?” were published in Jornal Brasileiro de Pneumologia (JBP).

This study compared spirometry (a measurement of lung function) results with variables related to the severity of sickle cell disease, history of asthma, and acute chest syndrome (ACS). They also evaluated pulmonary capacity using the six minute walk test (6MWT), which is commonly used as an indication of pulmonary hypertension.

The analysis included interviews, physical exams, and medical chart reviews obtained from 70 children and adolescents ages 8 to 15 with sickle cell disease who underwent pulmonary function tests or functional capacity testing in Belo Horizonte, Brazil.

Of the patients who underwent spirometry, 15 (23.4%) showed abnormalities: eight had restrictive lung disease (inhalation difficulty) and seven had obstructive lung disease (exhalation difficulty).

Of 69 patients with 6WMT results, 52.2% had significant blood oxygen level decreases of more than 3% (greater than 3% oxygen desaturation). This figure is higher than other studies, which reported blood oxygen level decreases in 18% and 34% of other patient populations. Because this study is the first of its kind in Brazil, the researchers identify this as a key area of future study and its “importance of functional assessment in this population.”

Additionally, the results of the 6WMT as a percentage of predicted value for age were below normal in 26.1% of the tested patients.

“The role of the 6MWT in children and adolescents with SCD has yet to be fully determined; however, it seems that > 3% oxygen desaturation (decrease) during the 6MWT may serve as an early marker of development of pulmonary hypertension in this population,” the researchers wrote.

They also found that asthma occurs in about one-third of children and teenagers with sickle cell disease, which is twice as prevalent compared to the same-age population without SCD. They suggest this also emphasizes the need for pulmonary function testing to begin in childhood.

In adult studies, a history of acute chest syndrome (ACS) was seen as a protective factor against pulmonary hypertension, the team noted, perhaps because of the treatments administered in acute situations. In this study, it seems to be the case as well, yet the team acknowledges that further studies must be conducted.