EFFECT OF PEAK FLOW MONITORING ON CHILD ASTHMA QUALITY OF LIFE

The purpose of this study was to evaluate the effect of peak flow monitoring (PFM) on asthma quality of life (QOL) for school-age children with asthma. Healthy People 2010 recommends that clinicians address factors that promote or hinder a family’s ability to manage asthma, with a focus on increasing QOL (U.S. Department of Health and Human Services [DHHS], 2000). QOL reflects disease control from the patient’s perspective, and its measurement has become an important objective of asthma management and research (National Asthma Education and Prevention Program [NAEPP], 2007).

The specific aims were to: (a) determine if asthma QOL improved over time with the use of PFM; (b) examine the relationship of PFM adherence and QOL; and (c) evaluate adverse health events (i.e., asthma attacks, health care utilization for asthma episodes, missed school days) and QOL. PFM was expected to improve asthma QOL over a 16-week period.

BACKGROUND

Asthma is a chronic respiratory condition affecting 10 million (14%) children in the U.S. under the age of 18 (Centers for Disease Control and Prevention [CDC], 2009). Asthma symptoms present as cough, wheeze, shortness of breath, and chest tightness. Episodes of inflammation and narrowing of the small airways in response to asthma triggers (e.g., allergens, infection, exercise, abrupt weather changes, or exposure to airway irritants) typify this disease (NAEPP, 2007).

Of those currently affected by asthma, approximately 4.1 million children reported at least one asthma attack in the previous 12 months (American Lung Association [ALA] 2010). As the leading cause of school absenteeism, asthma accounted for an estimated 14.4 million missed school days in 2008 (ALA, 2010). In 2006, 3.4 million (47 per 1000) visits to private physician offices, 500,000 (6 per 1000) hospital outpatient visits and 593,000 emergency department visits among children aged 0–17 years were attributed to asthma (Akinbami, Moorman, Garbe, & Sondik, 2009). Asthma remains the third leading cause of hospitalization among children younger than 15 years of age and resulted in 155,000 hospital visits (21 per 10,000) among children 0–17 years of age in 2006. Although asthma deaths are rare among children, 167 children ages 0–17 years died from this disease in 2005 (Akinbami et al., 2009). For 2010, the projected cost of treating asthma is $15.6 billion, and indirect costs related to lost productivity will add another $5.1 billion for a total of $20.7 billion (ALA, 2010). The burden that this disease and recommended treatment can place on children and their parents may affect the quality of their daily life. As part of the assessment of asthma treatment goals, it is critical to explore how this disease and its treatment may interfere with or improve the child’s QOL (NAEPP, 2007).

Asthma Quality of Life

Although there is no universal definition for health-related QOL, most QOL experts relate it to how individuals perceive and react to their health status and those aspects of their lives affected by the health condition and its treatment (Rapoff, 1999; Reddel et al., 2009). It is a multidimensional construct that includes physical health, activity, and emotional health (Chiang, 2005; Juniper et al., 2004; Reddel et al, 2009). Specific health conditions have different physical symptoms and recommended treatment. Thus, disease-specific measures are more useful than generic measures in assessing a patient’s perception of the impact of the particular disease and treatment process on QOL (Eiser & Morse, 2001).

The NAEPP Expert Panel (2007) recommends assessing four key areas of asthma QOL: (a) missed school days; (b) any reduction in usual activities; (c) sleep disturbances, and (d) any change in caregiver’s activities due to the child’s asthma. Education and adherence to prescribed treatment, leading to symptom relief and prevention of exacerbations, are positively associated with higher QOL for children with asthma and their families. That is, patients with better control of their asthma symptoms have a more positive QOL (Bloomberg et al., 2009; Georgiou et al., 2003; Schmier et al., 2007). Disease severity alone does not always correlate with well-being and functional ability (Kwok, Walsh-Kelly, Gorelick, Grabowski & Kelly, 2006; Skoner, 2001).

In a qualitative study of 36 children ages 9 to 15 years who were diagnosed with asthma, asthma interfered with factors related to well-being, especially peer interactions (Penza-Clyve, Mansell, & McQuaid, 2004). Children reported being embarrassed when taking medications in front of others and received verbal attacks from other children in response to their physical limitations. This led to medication avoidance by the children to prevent being viewed as different. They also reported feeling annoyed and tied down by burdensome medication schedules and that medicine side effects could be troublesome. Reduced motivation, difficulty remembering, social barriers and limits to accessibility were also identified. Overall, this combination of obstacles impedes adherence to prescribed treatment (Penza-Clyve et al., 2004) which can lead to exacerbations of symptoms, with resultant increased healthcare utilization.

The areas of physical functioning and family activities are key issues in child asthma QOL (Cicutto et al., 2005; Georgiou et al., 2003). In a study of 801 children with asthma, 53% of the children reported that they experienced some limitations, while 18% reported major limitations due to asthma (Fuhlbrigge, Guilbert, Spahn, Peden, & Davis, 2006). Maintaining an active lifestyle is an essential part of children’s routine. To minimize symptom exacerbation, children with asthma frequently restrict their physical activity (e.g., running, playing basketball, and playing outdoors). This is a burden for some children who want to fully participate in activities they enjoy (Fuhlbrigge et al., 2006; Skoner, 2001). Asthma symptom control lays the foundation for improving their QOL (Bloomberg et al., 2009; Bruzzese et al., 2004; Schmier et al., 2007).

Peak Flow Monitoring

The treatment goal for the pediatric patient with asthma is to reduce the frequency and severity of asthma symptoms so that the child can maintain normal activities. Delays in asthma treatment are frequently the result of inaccurate perceptions of symptom severity. Symptom perception of airway obstruction is generally poor for asthmatic children and their parents (Kotses, Harver, & Humphries, 2006; Harvener, Humphries, & Kotses, 2009; Yoos, Kitzman, McMullin, & Sidora, 2003) and has been associated with functional morbidity (Feldman et al., 2007). Monitoring pulmonary airflow is integral to asthma management. The most reliable objective measure of an asthma episode at home is a drop in peak expiratory flow (PEF). A peak flow meter is a simple device that can detect airway obstruction, often prior to the appearance of clinical signs. PFM is essential to: (a) assess the severity of asthma exacerbations; (b) detect early stages of asthma episodes; (c) monitor response to medication; and (d) establish an objective measure for detecting asthma triggers (NAEPP, 2007).

PFM is recommended for individuals who have moderate or severe persistent asthma (i.e., those patients experiencing daily symptoms or prescribed daily medication for symptom control) (NAEPP, 2007). With proper instruction on the importance of and the technique for using a peak flow meter (Callahan, Panter, Hal, & Slemmons, 2010), asthma patients can objectively measure their lung function and become actively involved in managing their asthma. This may result in improved health outcomes and better asthma QOL.

METHODS

Design

Data for this one-group pretest-posttest longitudinal study were collected at baseline, week 8, and week 16 of a randomized controlled trial that tested an intervention to promote children’s adherence to asthma self-management (Burkhart, Rayens, Oakley, Abshire, & Zhang, 2007; Burkhart, Rayens, Revelette, & Ohlmann, 2007). All children were taught how to use an electronic peak flow meter. Data collected at the three time points included: asthma quality of life, adherence to PFM, and adverse health events.

Sample

A convenience sample of 77 children with asthma and their parent or guardian was recruited from pediatric practices in central Kentucky. Inclusion criteria were: 7 through 11 years of age; English-speaking; diagnosed with moderate or severe persistent asthma (i.e., daily symptoms or prescribed daily controller medication) at least 6 months prior to study enrollment; and parent or guardian willing to participate with their child. Siblings of participants, children with other chronic conditions besides asthma, and children currently using a PEF meter on a daily basis were excluded.

The mean age of the children who completed the 16-week study was 9.1 years (SD = 1.4); they were predominantly male (58%, n = 45), Caucasian (79%, n = 61), and from two parent families (73%, n = 56). Most of the mothers and fathers had at least some college education (see Table 1).

Table 1.

Baseline Sociodemographic Characteristics of the Children in the Sample (N = 77)

Characteristic	n (%)
Sex
Male	45 (58)
Female	32 (42)
Age
7 years	21 (27)
8–9 years	32 (42)
10–11 years	24 (31)
Race
Caucasian	61 (79)
African-American	10 (13)
Other	6 ( 8)
Child lives with
Two Parents	56 (73)
One Parent	21 (27)
Education of father
< High School	5 ( 6)
High School	16 (21)
Some College or College Graduate	52 (68)
Did not know or no response	4 ( 5)
Education of mother
< High School	4 ( 5)
High School	9 (12)
Some College or College Graduate	64 (83)
Annual family income
>$60,000	32 (42)
$30,000 to $60,000	23 (30)
$15,000 to $29,999	14 (18)
< $15,000	8 (10)
Type of insurance
Public	10 (13)
Self Pay	2 ( 3)
Private	62 (80)
Other	3 ( 4)

Baseline asthma characteristics (Table 2) indicated that, on average, the children were diagnosed with asthma at about four years of age (M = 4.4, SD = 2.7). More than half of the children had a previous emergency department visit for asthma, but only one-third had ever been hospitalized for their asthma. Almost all of the children were prescribed daily asthma medications, including inhaled corticosteroids (61%, n = 47), yet only 12% (n = 9) had ever used a PFM. Compared with the previous year, 35% (n = 27) of the parents reported that the child’s asthma was better; 37% (n = 28) reported the child’s asthma was the same; and 28% (n = 21) reported the child’s asthma was worse.

Table 2.

Baseline Asthma Characteristics of the Children in the Sample (N = 77)

Characteristic	n (%)
Hospitalized for asthma
Yes	25 (33)
No	51 (66)
No Response	1 ( 1)
Emergency Department visits for asthma
Yes	45 (59)
No	31 (40)
Did not know	1 ( 1)
Ever used a peak flow meter (PFM)
Yes	9 (12)
No	65 (84)
Did not know what a PFM was	3 ( 4)
Child is on asthma medication:
Everyday	75 (98)
Few times a week	1 ( 1)
With symptoms only	1 ( 1)
Does your child take medication as directed?
All or most of the time	69 (90)
Some of the time	7 ( 9)
None of the time	1 ( 1)
Asthma Symptom Control
Very Good or Good	40 (52)
Fair	25 (32)
Poor	12 (16)

Measures

Asthma Quality of Life

Asthma QOL was measured using the Children’s Health Survey for Asthma [CHSA]. It was developed by the American Academy of Pediatrics [AAP] (2000) to address the impact of asthma and its medical treatment on the lives of children and their families. It is a self-report measure with a sixth grade reading level and is completed by the parents of 5- to 12-year-old children with chronic asthma. The instrument evaluates a broad spectrum of 48 child-focused items comprising five scales (Physical Health of the Child, Activity of the Child, Activity of the Family, Emotional Health of the Child, and Emotional Health of the Family). All scale items require a parent’s response on a 5-point Likert-type scale to recall information over the previous two months.

To test the instrument’s psychometric properties, more than 275 parents or guardians of school-age children with asthma across three samples completed the CHSA (Asmussen, Olson, Grant, Fagan, & Weiss, 1999). Internal consistency reliability for each of the scales was strong (Cronbach’s alpha = .81 to .92) and test-retest reliability ranged from .62 to .86. For the sample in the current study, Cronbach’s alpha for the 48 items was .95 at baseline.

For the purposes of this study, the three scales related to the child’s QOL will be discussed. All responses were self-reported by the parents as a proxy for their child. Parents were told that the purpose of the survey was to find out how much asthma affected the everyday life of their child.

Physical Health of the Child

Physical health of the child was defined as physical symptoms and pain experienced by the child and was assessed by 15 items, rated on a 5-point scale of 1 (all of the time) to 5 (none of the time). Questions included how often during the past 8 weeks the child experienced asthma symptoms (e.g., shortness of breath, wheezing, coughing) and side effects of asthma medications (e.g., headache, irritability, difficulty sleeping). In this sample, the reliability for the Physical Health of the Child subscale at baseline was .90.

Activity of the Child

Activity of the child was defined as the child’s ability to carry out everyday activities. The five scale items related to child activity (e.g., school gym classes, sports, and play) are rated on a 5-point scale of 1 (totally limited) to 5 (not limited). Cronbach’s alpha for this sample at baseline was .90

Emotional Health of the Child

Emotional health of the child was defined as the impact asthma has on the mental well-being of the child. It was assessed by five items related to frustration with dimensions such as having asthma, relying on asthma treatments, and activity limitations. A 5-point scale of 1 (all of the time) to 5 (none of the time) was used. Cronbach’s alpha for this sample at baseline was .93.

Each of the three scales is scored separately. Raw mean scale scores are computed by summing scale item responses and dividing the total score by the number of items completed. Raw mean scores are transformed to a 0–100 scale. Higher scores for each of the three scales indicate better or more positive outcomes (Asmussen, et al., 1999).

Asthma Health Outcomes

The CHSA also addresses the impact of asthma and medical treatment on the lives of children. The CHSA parent report was administered at weeks 1 (baseline), 8, and 16. The incidence of asthma episodes, health care utilization, and missed school days because of asthma for the prior two-month period were measured.

Asthma episodes

Asthma episodes were measured by CHSA item 2: During the past 2 months, how many times has your child had an asthma attack or trouble breathing when your child needed rest or extra medical care (such as more medicines or trips to the doctor)?

Health care utilization

Health care utilization was measured by CHSA items 3, 4, and 5: During the last two months because of problems with asthma, how many times has your child: (a) stayed overnight in the hospital; (b) been seen in the emergency department; (c) been seen in the doctor’s office or clinic for a sick visit?

Missed school days because of asthma

Missed school days because of asthma were measured by CHSA item 13, During the past 2 months, how many days of school did your child miss because of asthma?

Accutrax Personal Diary Spirometer

At-home adherence to daily PFM during the 16-week study was assessed by a computerized monitor, the Accutrax Personal Diary Spirometer (Ferraris Medical and PDS Instrumentation, Louisville, Colorado). This lightweight, handheld electronic monitor measures PEF and forced expiratory volume in the 1^st second (FEV₁). A built-in microchip records the date, time, and PEF value each time the device is used. It provides an objective measure of PFM adherence. Data can be stored in the device and downloaded to a computer for analysis. PEF data was downloaded at weeks 8 and 16 for all children and included PEF as well as the date and time PFM was performed. Adherence was defined as the proportion (expressed as a percentage) of electronically-recorded compared with prescribed PFM in each of the study periods, weeks 8 and 16.

Procedure

The study was approved by the medical institutional review board at a southern university. Interested parents of children with persistent asthma contacted the study group in response to recruitment flyers available in pediatric clinics, physician letters recommending the program, or through personal contact with the physician. During the initial phone contact with parents, the research nurse briefly described the study, determined eligibility, obtained verbal consent and scheduled the first face-to-face session. Children were accompanied by at least one parent to each of the sessions.

During week 1, all of the children (N = 77) and their parents received instruction on PFM and use of the AccuTrax PEF electronic monitor. Children were told to use the monitor in the morning and evening before taking their asthma medicine.

At the week 8 session, the research nurse reviewed the PFM process and the parents completed the CHSA for the prior 2-month period. After data collection at week 16, the AccuTrax monitor was replaced with the Truzone manual PEF meter (Monaghan Medical Corporation, Lebanon, Ohio) for continued home use by the child at the conclusion of the study.

Data Analysis

The longitudinal effect of PFM on asthma quality of life was assessed using repeated measures analysis of variance (ANOVA), with separate models for each asthma QOL dimension. For the ANOVAs with significant overall F-values, post-hoc analysis for the main effect of time was conducted using Fisher’s least significant difference procedure. The relationships between asthma QOL and adherence to PEF monitoring were assessed using two-sample t-tests, with adherence groups formed by an 80% cutoff. Two-sample t-tests were used to determine differences in asthma QOL between those with and without adverse health events in the last two months, including asthma attacks, emergency department visits due to asthma, acute care visits for asthma, and missed school days due to asthma. Data analysis was conducted using SAS for Windows; to control the overall Type I error rate in light of multiple comparisons, a Bonferroni-type correction was used to decrease the alpha level for individual tests.

RESULTS

Asthma Quality of Life

Child’s Physical Health

The repeated measures model for the physical health subscale of the CHSA was significant (F_{2, 152} = 41.7, p < .0001; see Figure), indicating that the main effect of time was significant. Post-hoc analysis of the child’s physical health scores at baseline, 8 weeks, and 16 weeks demonstrated that the means at 8 and 16 weeks were significantly greater than the mean at baseline (p < .01), suggesting an improvement in parent-rated child health post-baseline. The difference between weeks 8 and 16 was not significant.

Figure 1. Comparison of asthma quality of life subscale scores over time for the sample (N = 77).

Note. Significant differences for subscales at each time point are indicated by an asterisk.

Child’s Activity

The repeated measures model for the child’s activity over time was significant (F_{2, 153} = 10.9, p < .0001; see Figure). Post-hoc analysis indicated that the parent-rated child activity score was significantly greater at each of 8 and 16 weeks, compared with baseline (p < .01 for each comparison), while there was no change in child activity score between 8 and 16 weeks.

Child’s Emotional Health

For the outcome of parent rated child emotional health, the repeated measures ANOVA overall F test was significant (F_{2, 153} = 14.4, p < .0001), indicating that there was a significant change over time in this outcome (see Figure). Consistent with the other quality of life outcomes, post-hoc comparisons demonstrated a significant increase from baseline to week 8, and this was maintained at 16 weeks. In particular, the mean at baseline was significantly lower than the means at 8 and 16 weeks (p < .01 for each comparison). There was no difference between weeks 8 and 16.

Asthma Quality of Life and Adherence to PEF

There were no differences between adherent and non-adherent children on all three of asthma QOL scales at week 8. At week 16, the children who were adherent had a higher mean score for physical health (M = 88.6) compared with the physical health ratings for non-adherent participants (M = 80.6, t = 2.7, p = .01). There were no group differences on any other scale.

Asthma Quality of Life and Adverse Health Events

Examination of differences in QOL between those with health events in the two months prior to the survey and those without are shown in Table 3. Due to the number of comparisons for this analysis of the relationship between health events and QOL, an alpha of .001 was used. Children who did not experience one or more health events (asthma attacks, emergency department visits, health care provider visits, or missed school days due to illness) had better asthma QOL than those who experienced one or more health events (see Table 3). These differences in asthma QOL are particularly pronounced for the subscale that measures the child’s physical health.

Table 3.

Comparisons of Mean Scores of Children with No Health Event versus One of More Health Event in the 2 Months Prior to Each Survey

		Time
Outcome	Health Event (Asthma Related)	Baseline (yes/no)	8 weeks (yes/no)	16 weeks (yes/no)
Child’s	Asthma attack	65.9/84.7*	75.3/90.2*	76.8/89.7*
Physical	ED visit	66.4/70.8	54.7/81.3*	59.2/84.2
Health	Acute care visit	65.0/80.2*	70.1/85.7*	71.7/89.2*
	Missed school	63.5/77.4*	70.6/83.1*	66.7/88.5*
Child’s	Asthma attack	74.1/91.1*	80.8/91.7	75.6/94.5*
Activity	ED visit	70.6/79.0	56.0/85.4*	52.5/87.0
	Acute care visit	73.0/87.4*	75.3/88.7	76.6/90.7
	Missed school	72.2/84.3	74.5/87.3	73.5/89.7
Child’s	Asthma attack	59.1/82.2*	72.7/79.8	68.4/81.3
Emotional	ED visit	55.6/65.7	38.0/76.5*	17.5/77.2*
Health	Acute care visit	58.7/75.2	59.8/83.0*	65.0/80.9
	Missed school	60.7/70.0	58.1/80.0*	52.9/82.2*

Note. Group means that are significantly different from each other (with p ≤ .001) are indicated by an asterisk.

DISCUSSION

QOL improved for all children who were taught PFM as part of an asthma self-management program. Scores on all three QOL scales increased over time for participating children. For each outcome, there was a significant increase between baseline and Week 8 that was maintained in Week 16. These results indicate that teaching and reinforcing the use of PFM increases children’s physical health, activity, and emotional heath (as rated by the parent), and that these increases in QOL outcomes are maintained over a 4-month period.

Adherence to PFM was defined as use of the PFM at least 80% of the time (i.e., use of monitor at least 6–7 days a week). For children who were adherent during week 16, parent-rated child physical health was higher than for those who were non-adherent. Parents shared qualitatively that PFM, as an objective measure of the child’s symptom control, empowered them to intervene early as their child manifested asthma symptoms. It also allowed them to communicate more effectively with their healthcare provider.

Asthma QOL was higher for the children who did not experience the health events of one or more asthma attacks, emergency department visits, health care provider visits or missed school days due to illness. These differences in asthma QOL were particularly pronounced for the subscale that measured the child’s physical health.

The study was limited by use of self-reported asthma QOL by the parent as the child’s surrogate. Recall bias on the CHSA could be a concern, since parents were asked to report QOL indicators over the previous two-month period at three data collection points.

CONCLUSIONS

The results of this longitudinal study support the growing evidence that asthma self-management interventions, such as PFM aimed at providing data related to changes in airflow, can result in early intervention to improve symptom control. When asthma symptoms are controlled, children are less restricted in their ability to participate in various activities and experience less emotional distress. Since physical symptoms are a major indicator of asthma control, interventions designed to assist the child and parent to intervene early when asthma symptoms appear are crucial to promoting positive health-related QOL. In this study, PFM may have increased children’s awareness of their asthma symptoms that led to early intervention, resulting in improved symptom control. With the alleviation of asthma symptoms, children’s QOL scores improved.

Inadequately controlled asthma has a significant negative impact on asthma QOL (Bloomberg et al., 2009; Schmier et al., 2007). Findings of this study suggest that controlling asthma symptoms improves the QOL of children. When children were adherent to recommended asthma treatment, their asthma was better controlled.

Nurses providing care to children with asthma and their parents need to understand that appropriate asthma self-management can result in symptom control that impacts QOL. Nurses play a pivotal role as patient advocates for individualized care and educators about asthma self-management. Effective asthma management requires comprehensive assessment of the child’s and family’s ability to adhere to treatment and development of simple strategies to assist the child and family to manage the child’s asthma at home.