Validation of spirometry prediction equations in western Kenya

Area of Science:

• Respiratory Medicine
• Pulmonology
• Public Health

Background:

• Spirometry is crucial for diagnosing lung diseases.
• Existing prediction equations may not accurately reflect lung function in diverse populations.
• The performance of common spirometry equations in Kenyan adults is not well-established.

Purpose of the Study:

• To evaluate the accuracy of three widely used spirometry prediction equations in a healthy Kenyan population.
• To compare the performance of Global Lung Initiative 2012 (GLI 2012), NHANES III, and Crapo equations.
• To assess the utility of these equations for clinical application in Kenya.

Main Methods:

• Cross-sectional study of 282 healthy adults (18-85 years) in Eldoret, Kenya.
• Spirometry was performed, and lung function parameters were measured.
• Observed spirometry values were compared to predictions from GLI 2012 (African American), NHANES III (African American), and Crapo equations using Bland-Altman analysis.

Main Results:

• The GLI 2012 and NHANES III equations for African Americans showed similar performance.
• These equations significantly overestimated forced vital capacity (FVC).
• Observed forced expiratory volume in 1 second (FEV1) values were accurately predicted by the best-performing equations.

Conclusions:

• The study questions the applicability of the evaluated spirometry prediction equations in the Kenyan population.
• Significant overestimation of FVC suggests these equations are not suitable for Kenyan adults.
• Further research is needed to develop population-specific spirometry prediction equations for Kenya.