Correlation Between the Asthma Control Test Score and FEV1 in Nigerians With Bronchial Asthma

Abstract

PURPOSE: The aim of asthma therapy is to achieve control. Although the pre-bronchodilator FEV1 is an objective means of assessing asthma control, facilities for its assessment are not routinely available to all patients in our practice setting due to funding and manpower limitations. The Asthma Control Test (ACT) is a simple validated questionnaire for assessing asthma control but its reliability in comparison to objective measures such as the FEV1 has not been established in our patients. This study aimed to explore the correlation between ACT and the pre-bronchodilator FEV1 in Nigerians with bronchial asthma and therefore establish its value in our population.METHODS: Forty six patients with asthma attending our tertiary care centre completed the ACT and had their pre-bronchodilator FEV1 measured on the same visit. Demographic and anthropometric data were also obtained. Normal FEV1 was defined as 80% of the predicted. ACT scores were graded as good (≥20), poor (≥14and ≤19) and very poor (< 14). The correlation between the ACT score and FEV1 was determined statistically.RESULTS: The mean age ±SD (years) was 42.6±15.1. There were 29 (63%) females and 17 (37%) males. The mean BMI ±SD (kg/m2) for females was 24.0±6.2 and 23.7±3.4 for males (P>0.05). The mean ±SD FEV1 (Liters) was 1.9±0.8. FEV1 was normal in 27(58.7%) of the subjects and reduced in 19 (41.3%). The mean ±SD ACT score was 18.3±4.7. Twenty two (47.8%) subjects had ACT scores indicative of good asthma control, 15(32.6%) had scores for poor control and 9(19.6%) had scores for very poor control. The correlation co-efficient r^2 between the ACT score and the FEV1 was 0.14 (P=0.01) and the standardized coefficient beta was 0.376 (95% confidence interval 0.017 - 0.116). ACT score graded as normal also correlated significantly with normal FEV1 (Z=2.4. P=0.2).CONCLUSION: The ACT score correlates positively with the FEV1 in Nigerians with bronchial asthma.CLINICAL IMPLICATIONS: The ACT is therefore a useful tool for assessing asthma control as an interim measure in practice circumstances where spirometry is not readily available.DISCLOSURE: Obianuju Ozoh, No Financial Disclosure Information; No Product/Research Disclosure Information