Longitudinal Relationships between Asthma-Specific Quality of Life and Asthma Control in Children; The Influence of Chronic Rhinitis

Abstract

Abstract: Managing pediatric asthma includes optimizing both asthma control and asthma-specific quality of life (QoL). However, it is unclear to what extent asthma-specific QoL is related to asthma control or other clinical characteristics over time. The aims of this study were to assess in children longitudinally: (1) the association between asthma control and asthma-specific QoL and (2) the relationship between clinical characteristics and asthma-specific QoL. In a 12-month prospective study, asthma-specific QoL, asthma control, dynamic lung function indices, fractional exhaled nitric oxide, the occurrence of exacerbations, and the use of rescue medication were assessed every 2 months. Associations between the clinical characteristics and asthma-specific QoL were analyzed using linear mixed models. At baseline, the QoL symptom score was worse in children with asthma and concomitant chronic rhinitis compared to asthmatic children without chronic rhinitis. An improvement of asthma control was longitudinally associated with an increase in asthma-specific QoL (p-value < 0.01). An increased use of β₂-agonists, the occurrence of wheezing episodes in the year before the study, the occurrence of an asthma exacerbation in the 2 months prior to a clinical visit, and a deterioration of lung function correlated significantly with a decrease in the Pediatric Asthma Quality of Life Questionnaire (PAQLQ) total score (p-values ≤ 0.01). Chronic rhinitis did not correlate with changes in the PAQLQ score over 1 year. The conclusion was that asthma control and asthma-specific QoL were longitudinally associated, but were not mutually interchangeable. The presence of chronic rhinitis at baseline did influence QoL symptom scores. β₂-agonist use and exacerbations before and during the study were inversely related to the asthma-specific QoL over time.

Keywords: asthma; asthma-specific quality of life; children; chronic rhinitis; disease-specific quality of life; health-related quality of Life (HRQLQ); longitudinal study.

Figure 1

Overview of the course of the PAQLQ and ACQ scores during 12 months. On the right-hand side, the scale and numbers of the ACQ score are given, on the left-hand side, the scale and numbers of the PAQLQ score.

Figure 2

Associations between ACQ asthma control and PAQLQ total scores in a linear mixed model―all measurements taken during one year were included. The regression line is based on a model in which the ACQ level of asthma control is included; the estimates of this model are given in Table 3. For factors in the equation other than ACQ asthma control, mean values were used. ACQ asthma control: 0 = uncontrolled, 1 = partly controlled, and 2 = controlled.

Figure 3

Associations between β₂-agonist use and the PAQLQ total score in a linear mixed model―all measurements taken during one year are included^†. * Use of rescue medication during the week preceding the clinical visit: 0 = 0 puffs most days, 1 = 1–2 puffs most days, 2 = 3–4 puffs most days, 3 = 5–8 puffs most days, 4 = 9–12 puffs most days, 5 = 13–16 puffs most days, and 6=more than 16 puffs most days. The regression line is based on the model in which the asthma control levels were excluded, the estimates of this model are given in Table 4. For factors in the equation other than the use of rescue medication, mean values were used.

Figure 4

Associations between lung function and the PAQLQ total score in a linear mixed model―all measurements taken during one year were included. The regression line is based on the model in which the asthma control levels were excluded, the estimates of this model are given in Table 5. For factors in the equation other than the FEV₁ percentage of the predicted value, mean values were used.