Prevalence, patterns and factors associated with spirometry abnormalities among children and adolescents with sickle cell disease in northern and eastern Uganda: a cross-sectional study.

BACKGROUND: Abnormal spirometry indices are known to be early markers of long-term respiratory dysfunction in the sickle cell disease (SCD) population. In Sub-Saharan Africa, however, evidence remains scarce. This study aimed to assess the prevalence, patterns, and factors associated with spirometry abnormalities among children and adolescents with homozygous SCD in Uganda. METHODS: A cross-sectional study was conducted between september and december 2025 at Jinja and Lira Regional Referral Hospitals. Clinically stable children aged 6-18 years with confirmed homozygous SCD were consecutively enrolled. Sociodemographic and clinical data were collected using structured questionnaires, and spirometry was performed and results were interpreted using the Global Lung Initiative 2012 reference equations (GLI-12). Logistic-regression models identified factors independently associated with spirometry abnormalities. RESULTS: Among 362 participants (mean age 11.7 ± 3.2 years; 53.1% male), 41.7% had abnormal spirometry. The restrictive spirometry pattern predominated (67.5%), followed by obstructive (27.8%) and mixed (4.6%) patterns. The odds of abnormal spirometry increased threefold among children 8-12 years (aOR = 3.346; 95% CI 1.375-8.142; p = 0.008) and rose over thirteen-fold in adolescents 13-18 years (aOR = 13.532; 95% CI 5.687-32.201; p < 0.001). Being underweight was associated with a four-fold higher risk (aOR = 3.871; 95% CI 2.189-6.845; p < 0.001). Children who had not completed all recommended pneumococcal-conjugate-vaccine (PCV) doses had a 3.5-fold greater risk (aOR = 3.474; 95% CI 1.618-9.153; p = 0.022). A history of recurrent acute chest syndrome was also associated with spirometry abnormalities (aOR = 3.295; 95% CI 1.016-14.526; p = 0.044). CONCLUSION: Spirometry abnormalities were highly prevalent among children and adolescents with SCD in Northern and Eastern Uganda, with a predominance of restrictive spirometric patterns. Increasing age, undernutrition, incomplete pneumococcal vaccination, and previous ACS episodes were independently associated with abnormal spirometry. These findings support the integration of routine spirometry testing and surveillance into pediatric SCD care in the clinical setting.