Asthma severity and child quality of life in pediatric asthma: A systematic review

Abstract

Objective

To systematically review evidence of asthma severity as a correlate of child quality of life (QOL) in pediatric asthma.

Methods

Online bibliographic databases (PsycINFO, PsycARTICLES, and MEDLINE) were used to identify relevant studies that specifically considered the relationship between asthma severity and child QOL.

Results

Fourteen studies matching inclusion and exclusion criteria were reviewed. Asthma severity was significantly related to child QOL in nine of these studies. Informant of QOL and type of QOL measure were found to influence the strength of the relationship between severity and child QOL in pediatric asthma.

Conclusions

Findings suggest that asthma severity is a correlate of child QOL. Children whose asthma symptoms are not well-managed are likely to experience an impaired level of QOL. Findings also suggest the need to utilize asthma-specific QOL measures and an informant of QOL other than the child's parent in order to receive the most accurate information about the child's level of functioning.

Practice implications

Researchers and healthcare providers basing clinical outcomes on QOL assessments should consider asthma severity in their evaluations. Further, researchers and healthcare providers should recognize the continued need to reduce asthma severity and improve asthma symptom control in their attempts to improve the QOL of children with asthma.

Introduction

Clinicians and researchers routinely use quality of life (QOL) as an indicator of treatment success in pediatric asthma. Measures of QOL are thought to indicate how much an individual's illness interferes with daily life and how well the patient is adapting to his or her illness across several areas of functioning such as social, emotional, and physical [1]. Thus, QOL assessments are used to measure the effectiveness of medical treatments and other interventions in improving patient functioning and adaptation to a chronic illness [2]. Healthcare providers who treat children with asthma often utilize these outcome measures in their decisions about treatment planning and medication usage. However, the relationship between disease severity and child QOL in pediatric asthma is not well established. For example, symptoms of poorly controlled asthma such as wheezing and night-time waking, thought to disrupt daily and nightly activities, are not consistently associated with measurements of child QOL in some studies [3], [4], whereas other studies report such relationships [5], [6]. Thus, the overall aim of this review was to evaluate the degree to which asthma severity is a correlate of child QOL across several studies.

In pediatric asthma, the lack of a consistent relationship between asthma severity and child QOL may be due to inconsistencies in the way in which asthma severity is measured (e.g., symptoms, limited activities, night waking and pulmonary function tests). As QOL is conceptualized as being comprised of patient functioning across several domains (e.g., physical, psychological and social), factors related to asthma severity should influence child QOL [7]. Yet, the inconsistent relationship between severity and QOL suggests that factors independent of physical indicators may instead influence child QOL [8]. It might also be that the relationship between severity and child QOL holds only under certain conditions or depending upon how severity is measured. For instance, asthma severity is often classified based on patient and/or caregiver retrospective recall of symptoms or according to physician judgment following published guidelines for asthma care [9].

There is little agreement among researchers as to which methods to use to classify asthma severity [10]. For instance, a researcher may utilize the guidelines from National Heart, Lung and Blood Institute (NHLBI) or guidelines from the National Asthma Education and Prevention Program (NAEPP) in determining severity. Guidelines from the NHLBI rely on several variables for classifying asthma severity: medication usage, lung function, symptoms, symptom interference with normal activities, and night-time waking [11]. The NAEPP, which is an initiative of the NHLBI, utilizes three techniques for classifying severity: frequency of asthma symptoms during the day, frequency of nighttime asthma symptoms, and measures of pulmonary function [11]. Still other researchers might rely on other national guidelines depending on the location of their study (e.g., the British Guidelines on the Management of Asthma). Ortega et al. [12] speculate that there is such a variety of ways to classify asthma severity, in part, because health professionals are unsure of which factors should be utilized to evaluate asthma severity. Thus, in assessing the relationship between asthma severity and child QOL, this review considered how classification of asthma severity might influence this relationship.

Based on previous reviews evaluating the psychometric properties of QOL measures in pediatric populations [13], [14], [15], [16], [17], [18], this review also considered type of QOL measure (e.g., generic vs. disease-specific) and informant (e.g., parent vs. child) in the relationships between asthma severity and child QOL. For instance, generic QOL measures are used to measure multiple domains of functioning related to QOL and can be used with healthy and ill populations [15]. Disease-specific measures report on a person's QOL as it relates specifically to a certain medical condition. Generic measures, therefore, allow for comparisons across diseases and between healthy and ill individuals. Disease-specific measures do not have such flexibility, but are considered more sensitive to clinical changes [15]. With respect to informant choice, it is often suggested that based on the cognitive and emotional development of children, young children are not able to accurately report on their current level of QOL [7], [14]. To combat such issues related to child report, certain QOL measures are designed for completion by the child's parents. However, this methodology is also cause for concern in that parent report of child QOL is likely to be influenced by parental biases and expectations [14]. Parent report can also obscure the accuracy of a child's symptoms or functioning if the parent is emotionally distressed [3]. In fact, the results of a parent-completed child QOL measure may be quite different from the child's actual experience with his or her illness.

Therefore, in assessing asthma severity as a correlate of child QOL, our review had three goals. First, we aimed to examine whether classification of asthma severity influenced the relationship between asthma severity and child QOL. We identified three ways that asthma severity was classified in our studies: (1) from parent or child report of asthma symptoms, (2) published guidelines and (3) medication usage criteria from published guidelines. Second, we sought to determine whether the type of QOL instrument utilized (e.g., generic vs. disease-specific) influenced the strength of this relationship. Finally, we considered whether informant of child QOL (e.g., child vs. parent) altered the strength of the relationship between asthma severity and child QOL in pediatric asthma.