Relationships among quality of life, severity, and control measures in asthma: An evaluation using factor analysis

doi:10.1016/j.jaci.2005.02.008

Journal of Allergy and Clinical Immunology

Volume 115, Issue 5, May 2005, Pages 1049-1055

https://doi.org/10.1016/j.jaci.2005.02.008 Get rights and content

Background

Validated psychometric tools measuring quality of life, asthma control, and asthma severity have been developed, but their relationships with each other and with other important patient-centered outcomes have not been rigorously assessed.

Objective

To use factor analysis to evaluate the relationships of these validated tools with each other and with other patient-centered outcomes.

Methods

Surveys were completed by a random sample of 2854 Health Maintenance Organization members age 18 to 56 years with persistent asthma. Surveys included demographic information; validated tools measuring generic (Short Form-12; SF-12) and asthma-specific (Juniper Mini Asthma Quality of Life Questionnaire; AQLQ) quality of life, asthma control (Asthma Therapy Assessment Questionnaire), and asthma symptom severity (Asthma Outcomes Monitoring System); self-described severity, control, and course over time; and history of acute exacerbations.

Results

Principal component analysis suggested a 5-factor model that accounted for approximately 59% of the variability. The most prominent rotated factor reflected asthma symptom frequency (19.4% of variability), was measured by the symptom subscale of the AQLQ, and was the only factor significantly related to the Asthma Therapy Assessment Questionnaire, Asthma Outcomes Monitoring System, or the self-reported assessments of severity, control, or course. Other factors included symptom bother (12.1% of variability), reflected by the environment and emotion AQLQ subscales; activity limitation (13.9% of variability), reflected by the activity AQLQ subscale and the SF-12 physical component scale; mental health (8.3% of variability), reflected by the SF-12 mental component scale; and acute exacerbations (5.0% of variability), not measured by any of the validated scales.

Conclusion

Distinct components of patient-reported asthma health status can be identified by factor analysis. Distinct constructs of severity versus control cannot be identified by the use of these tools alone.

Section snippets

Patients

Surveys were sent in August 2000 to a random sample of Kaiser-Permanente Medical Care Program adult (age 18 to 56 years) members with persistent asthma from the Northern California (n = 3072), Northwest (n = 543), and Southern California (n = 3251) regions. Persistent asthma was diagnosed on the basis of the presence of 1 or more of the following administrative database criteria (during 1999): (1) 4 or more asthma medication dispensings, (2) 1 or more emergency department visits or hospitalizations

Results

The demographic characteristics of the study populations are shown in Table I. The majority of the patients were white, female, well educated (at least some college), nonpoor (annual income >$35,000), and nonsmokers.

On the basis of the Eigenvalues of the factors in the principal component analysis, a 5-factor model was chosen (which explained 59% of the variability). After rotation, all but 1 of the 53 factors loaded significantly on at least 1 of the 5 factors—asthma symptom frequency, asthma

Discussion

This study identified 5 distinct factors or domains (Table II) from a survey assessing the asthma patient experience by using several validated tools. The most prominent factor is symptom frequency, which appears to be separate from the domains of symptom bother, activity limitation, and acute exacerbations. Strengths of this study include the large number of patients surveyed, the use of validated tools, the relatively homogenous medical care system that served the participants, the real world

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Relationship between health-related quality of life and subjective wellbeing in asthma
2021, Journal of Psychosomatic Research
Poor health-related quality of life (HRQoL) is associated with a high risk of acute exacerbations in patients with asthma. The use of health state utility instruments to measure HRQoL is common, but it has been criticised for failing to adequately capture the impact of the condition from the patient perspective. We aimed to assess the ability of subjective wellbeing and health state utility instruments to capture important HRQoL dimensions for asthma patients.
Regression analyses were conducted using data (n = 856 asthma patients) from a large multi-national cross-sectional survey to explore the relationship between subjective wellbeing (ONS4, PWI, SWLS), health state utility (15D, AQoL-8D, EQ-5D-5L, HUI3, SF-6D, SF-6Dv2), and an asthma-specific instrument (AQLQ-S). The latent structure of different instruments was investigated using an exploratory factor analysis.
All instruments could distinguish the impact of asthma on HRQoL. Among health utility instruments, 15D, SF-6D and AQoL-8D were more sensitive based on the average standardised regression coefficients. AQOL-8D had the strongest correlation with subjective wellbeing. Nevertheless, the exploratory factor analysis showed a complementary relationship between subjective wellbeing and HRQoL instruments. The most important subjective wellbeing domains were standard of living, achieving in life, and personal relationships; although contributions of these domains to overall life satisfaction differed among asthma patients identified by a latent class analysis.
The use of subjective wellbeing alongside AQLQ-S and health state utility instruments provides a comprehensive approach to assess the impact of asthma on the patient's life. Further research is needed to incorporate these measures in health care evaluation.
Quality of Life and Asthma Symptom Control: Room for Improvement in Care and Measurement
2015, Value in Health
The recent Global Initiative for Asthma management strategy recommends achieving symptom control and minimizing the future risk of poor outcomes as priorities for asthma management.
The objective was to quantify the association between symptom control and health-related quality of life in asthma.
In a prospectively recruited random sample of adults with asthma, we ascertained symptom control and measured health-related quality of life using a generic (EuroQol five-dimensional questionnaire [EQ-5D]) and a disease-specific (Asthma Quality of Life Questionnaire) instrument, to estimate EQ-5D and five-dimensional Asthma Quality of Life Questionnaire (AQL-5D) utilities, respectively. We measured the adjusted difference in utilities across symptom control levels and calculated the loss of predictive efficiency due to aggregating multiple symptoms into one symptom control variable.
The final sample included 958 observations from 494 individuals (mean age at baseline 52.2 ± 14.5 years; 67.0% women). Asthma was symptomatically controlled, partially controlled, and uncontrolled in 269 (28.1%), 367 (38.3%), and 322 (33.6%) observations, respectively. A person with symptomatically uncontrolled asthma would gain 0.0512 (95% CI 0.0339–0.0686) in EQ-5D or 0.0802 (95% CI 0.0693–0.0910) in AQL-5D utilities by achieving symptom control. The loss of predictive efficiency was 55.4% and 27.6% for EQ-5D and AQL-5D utilities, respectively.
Asthma symptom control status corresponds well with both generic and disease-specific quality-of-life measures. The trade-off, however, between ease of use and predictive power should be reconsidered in developing simplified measures of control. Our results have direct relevance in informing decision-analytic models of asthma and deducing the effect of interventions on quality of life through their impact on asthma control.
Assessing the validity of the RAND negative impact of asthma on quality of life short forms
2014, Journal of Allergy and Clinical Immunology
Citation Excerpt :
The Asthma Control Test (ACT)28 was used to measure asthma control, a multidimensional construct that encompasses both symptoms and use of rescue medications and the impact of asthma on daily functioning. The ACT consists of 5 items and has strong psychometric properties, including good internal consistency, test-retest reliability, validity, and responsiveness.17,29,30 Scores on this 5-item measure range from 5 to 25, with cutoffs of 5 to 15 (poorly controlled), 16 to 19 (somewhat controlled), and 20 to 25 (well controlled).
In response to recommendations from the 2010 National Institutes of Health Asthma Outcomes Workshop, we developed a system for measuring the negative impact of asthma on quality of life (QoL), which was referred to as the RAND Negative Impact of Asthma on Quality of Life (RAND-IAQL) item bank. The bank contains 65 items that focus on the patient's perception of the impact or bother of asthma on his or her life.
Evidence for the validity of 2 short forms, the RAND-IAQL 4-item and 12-item Short Forms, from the bank is presented.
Using a sample of 2032 adults with asthma, we validated our short forms against the Asthma Quality of Life Questionnaire–Marks (AQLQ-M), the Asthma Control Test, and generic measures of QoL developed by the Patient-reported Outcomes Measurement Information System (PROMIS). Discriminant validity was examined by comparing scores of respondents who differed according to multiple health indicators.
Our sample ranged in age from 18 to 99 years (mean, 43 years), with 14% Hispanic, 11% Asian, 19% African American, and 56% non-Hispanic white race/ethnicity. Men had a significantly worse impact of asthma on QoL than women. The impact of asthma on QoL was greatest in African American and Hispanic subjects compared with that seen in non-Hispanic white subjects. Our measures correlated highly with the AQLQ-M and more strongly with the PROMIS global physical than mental scales. They differentiated between adults with asthma according to their perceived severity, level of control, presence or absence of exacerbations, and physical comorbidity.
The RAND-IAQL item bank, measuring the impact of asthma on QoL, will complement other patient-reported outcomes, such as measures of asthma symptoms, functioning, and control.
Real-time asthma outreach reduces excessive short-acting β<inf>2</inf>-agonist use: A randomized study
2014, Journal of Allergy and Clinical Immunology: In Practice
Excessive use of short-acting β₂-agonists (SABA) indicates impaired asthma control.
To determine whether real-time outreach to excessive SABA users reduces SABA canister dispensings.
After real-time determination of a seventh SABA canister dispensing in the prior 12 months by using informational pharmacy technology, 12 to 56 year old patients with physician-coded asthma and inhaled corticosteroid dispensing were block randomized by prior asthma specialist care and medication step-care level into intervention (n = 1001) and control groups (n = 998). Intervention included real-time letter notification to patients and an electronic message to their physician with management suggestions, including facilitated allergy referral for patients without prior asthma specialist care. The control group received this organization’s standard asthma care management without research contact. Frequency of the seventh SABA canister dispensing in the follow-up year was the primary outcome.
Compared with controls, intervention patients reached 7 SABA canister dispensings less frequently (50.7% vs 57.1%; risk ratio 0.89 [95% CI, 0.82-0.97]; P = .007) and later (hazard ratio 0.80 [95% CI, 0.71-0.91; P < .001). SABA canister dispensings (mean ± SD) were less in intervention (7.5 ± 4.9 canisters) than controls (8.6 ± 5.3 canisters) (rate ratio 0.87 [95% CI, 0.82-0.93]; P < .001). The intervention reduced the risk of ≥7 SABA canister dispensings in patients without specialist care compared with patients with specialist care in the prior 3 years (P < .001) (P = .04 for interaction by prior specialist care). Visits to allergists were more frequent for intervention patients (30.9%) than for control patients (16.8%) (risk ratio 1.83 [95% CI, 1.54-2.16]; P < .001). Asthma exacerbations were unaffected.
A novel administrative-based asthma outreach program improves markers of asthma impairment in patients without prior asthma specialist care and is adaptable to managed care organizations with electronic medical records.
Airway obstruction lability helps distinguish levels of disease activity in asthma
2012, Respiratory Medicine
Classifying disease activity in asthma relies on clinical and physiological variables, but these variables do not capture all aspects of asthma that distinguish levels of disease activity.
We used data from two pivotal trials of montelukast in asthma to classify disease activity as “high” or “low.” We performed a principal component analysis (PCA) of disease activity using 21 efficacy outcome variables, including several novel derived outcome variables reflecting clinical and airway obstruction lability. Then we performed discriminant analysis (DA) based on disease activity classification.
PCA revealed 6 factors (daytime asthma control, nighttime-predominant asthma control, airway obstruction, exacerbations, clinical lability, airway obstruction lability) that explained 76% of the variance between outcome variables. Although airway obstruction lability (comprising both diurnal variability in peak expiratory flow and diurnal variability in β-agonist use) accounted for only 6% of the explained variance in PCA, in DA it was more accurate (canonical coefficient 0.75) than traditional measures of asthma severity such as obstruction (−0.54) and daytime control (−0.56) in distinguishing between high and low disease activity.
We conclude that airway obstruction lability, a parameter not typically captured in clinical trials, may contribute to more complete assessment of asthma disease activity and may define an emerging clinical target of future therapy.
Asthma outcomes: Quality of life
2012, Journal of Allergy and Clinical Immunology
“Asthma-related quality of life” (QOL) refers to the perceived impact that asthma has on the patient’s QOL.
National Institutes of Health institutes and other federal agencies convened an expert group to recommend standardized measures of the impact of asthma on QOL for use in future asthma clinical research.
We reviewed published documentation regarding the development and psychometric evaluation; clinical research use since 2000; and extent to which the content of each existing QOL instrument provides a unique, reliable, and valid assessment of the intended construct. We classified instruments as core (required in future studies), supplemental (used according to the study’s aims and standardized), or emerging (requiring validation and standardization). This work was discussed at an National Institutes of Health-organized workshop convened in March 2010 and finalized in September 2011.
Eleven instruments for adults and 6 for children were identified for review. None qualified as core instruments because they predominantly measured indicators of asthma control (symptoms and/or functional status); failed to provide a distinct, reliable score measuring all key dimensions of the intended construct; and/or lacked adequate psychometric data.
In the absence of existing instruments that meet the stated criteria, currently available instruments are classified as either supplemental or emerging. Research is strongly recommended to develop and evaluate instruments that provide a distinct, reliable measure of the patient’s perception of the impact of asthma on all of the key dimensions of QOL, an important outcome that is not captured in other outcome measures.

View all citing articles on Scopus

: Supported by the Kaiser-Permanente Care Management Institute, Oakland.

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Health care education, delivery, and qualityRelationships among quality of life, severity, and control measures in asthma: An evaluation using factor analysis

Background

Objective

Methods

Results

Conclusion

Section snippets

Patients

Results

Discussion

J Clin Epidemiol

J Allergy Clin Immunol

Ann Allergy Asthma Immunol

J Allergy Clin Immunol

Respir Med

Ann Allergy Asthma Immunol

Am J Med

Surveillance for asthma—United States, 1980-1999

MMWR Surveill Summ

Development and validation of the Mini Asthma Quality of Life Questionnaire

Eur Respir J

Asthma Outcomes Monitoring System (AOMS) administration, scoring, and interpretation manual

Association of asthma control with health care utilization and quality of life

Am J Respir Crit Care Med

Development and validation of a questionnaire to measure asthma control

Eur Respir J

Health care education, delivery, and quality
Relationships among quality of life, severity, and control measures in asthma: An evaluation using factor analysis