Daytime and Nighttime Visual Analog Scales May Be Useful in Assessing Asthma Control Levels Before and After Treatment

PURPOSE: Few questionnaires evaluate daytime and nighttime symptoms separately, although these assessments could contribute to the improvement of disease control levels and prevention of future risks in asthma. The purpose of this retrospective study was to investigate whether daytime and nighttime visual analog scales (VAS) are useful in measuring the perception of symptoms, assessing disease control levels, and evaluating the treatment effects in asthma. PATIENTS AND METHODS: Self-reporting asthma control tests (ACT) before and after treatment are standardized tests used to determine disease control levels. A multiple regression analysis was performed to determine the correlation between daytime and nighttime VAS and the characteristics of patients before treatment, as well as the changes in VAS and lung functions and fractional exhaled nitrogen oxide after treatment in 55 treatment-naïve symptomatic adult patients with asthma. RESULTS: Both daytime (r = −0.57, P < 0.0001) and nighttime (r = −0.46, P < 0.0001) VAS correlated well with ACT scores, and there was a correlation between daytime and nighttime VAS (r = 0.33, P = 0.0148) before treatment. In addition, the changes in daytime (r = −0.65, P < 0.0001) and nighttime (r = −0.44, P < 0.0001) VAS were significantly associated with changes in the ACT scores. The multiple regression analysis (β [95% confidence interval]) revealed that improvements in the daytime (−2.33 [−4.55 to −0.11], P = 0.0405) and nighttime (−3.09 [−6.25 to 0.07], P = 0.0505) VAS were associated with an increased forced vital capacity after treatment, although there was no correlation between the VAS and characteristics before treatment. CONCLUSION: Our study demonstrated that daytime and nighttime VAS were useful in assessing disease control levels and evaluating the treatment effects in asthma.