ORIGINAL ARTICLE
Poor Asthma Control Among US Workers Health-Related Quality of Life, Work Impairment, and Health Care Use Jeffrey Vietri, PhD, Kate Burslem, MSc, and Jun Su, PhD
Objective: This study examined the impact of asthma control on healthrelated outcomes among employed US asthma sufferers treated with prescription medicines. Methods: Data from the 2011 National Health and Wellness Survey (N = 75,000) were used. The Asthma Control Test, validated measures of health-related quality of life, work productivity and activity impairment, and questions assessing health care use were included. Results: Of the 2026 employed asthma sufferers treated with prescription medicines included, 39.7% had Asthma Control Test scores indicating poorly controlled asthma. After adjusting for covariates, workers with poorly controlled asthma had worse health-related quality of life, work and activity impairment, and more health care use than those with well-controlled asthma. Conclusions: Poorly controlled asthma in employed patients treated with prescription medicines is common, and associated with negative health outcomes. Workers, employers, and payers could all benefit from improvements in asthma control.
A
sthma is a highly prevalent chronic inflammatory disorder that causes the airways to swell and narrow, leading to shortness of breath, coughing, and tightening of the chest.1,2 Asthma is common in the United States, affecting 9.5% of children and 7.7% of adults.3 Whereas no gold standard exists for defining asthma severity,4,5 severe asthma has been estimated to affect approximately 5 to 10% of those diagnosed with this condition.6–8 Asthma is associated with substantial costs, with direct medical costs in the United States estimated at $30 billion to $50 billion annually.9,10 A significant proportion of these costs is associated with emergency department visits, hospitalizations, and death, thus emphasizing the importance of appropriate management to maintain asthma control.11 Treatment guidelines have been established to promote effective clinical control through symptom reduction and prevention of exacerbations (asthma attacks), thus enabling sufferers to maintain normal functioning and activity.12 Although adequate control can be achieved in most patients through appropriate treatment and followup, many do not achieve adequate control and continue to suffer attacks.13,14 There are a number of patient and provider-based barriers to effective asthma control. These include poor patient adherence with treatment recommendations, inadequate treatment follow-up, as well as the impact of comorbid disease (eg, obesity15 ). For example, evidence suggests that despite the existence of treatment guidelines, some clinicians may be reluctant to adopt newer guidelines if they believe their current practice is effective.16 Furthermore, asthma is From the Health Outcomes Practice (Dr Vietri), Kantar Health, Princeton, NJ; and Boehringer Ingelheim Pharmaceuticals, Inc (Mr Burslem and Dr Su), Ridgefield, Conn. This work was conducted by Kantar Health and funded by Boehringer Ingelheim Pharmaceuticals, Inc (BIPI). Dr Vietri is an employee of Kantar Health and Dr Su and Mr Burslem are employees of BIPI. The authors declare no other conflicts of interest. Supplemental digital content is available for this article. Direct URL citation appears in the printed text and is provided in the HTML and PDF versions of this article on the journal’s Web site (www.joem.org). Address correspondence to: Jeffrey Vietri, PhD, Kantar Health, 1 Independence Way, Suite 220, Princeton, NJ 08540 ([email protected]). C 2014 by American College of Occupational and Environmental Copyright Medicine DOI: 10.1097/JOM.0000000000000123
a chronic condition that requires long-term management, and thus patient adherence to recommended treatment is often a challenge (for an overview, see Long17 ). A recent study by Cantrell and colleagues18 noted that, on the basis of US health insurance claims data, only 35% of asthma sufferers were considered compliant with treatment guidelines. Importantly, evidence suggests that inadequate asthma control can be associated with a host of negative outcomes, including impaired work productivity, impaired quality of life, increased rates of depression and anxiety, and greater health care costs and use of health care resources.14,19–28 A previous article by Williams and colleagues26 examined the impact of asthma control in a representative sample of US patients. They reported that those whose asthma was controlled had better health-related quality of life (HRQoL), lower health care resource utilization, and less work productivity impairment than those with uncontrolled asthma. The majority of patients experiencing asthma attacks are of working age,29,30 and a large proportion of patients are treated with prescription medications.31 The objective of this study was to evaluate the impact of asthma control on outcomes among employed asthma sufferers who are taking prescription medication for asthma treatment, since this may represent a significant burden on US employers, both in terms of health care costs and lost productivity.
METHODS Sample and Procedure
This study included data from the 2011 (N = 75,000) US National Health and Wellness Survey (NHWS). The NHWS is a self-administered, Internet-based questionnaire from a nationwide sample of adults (aged 18 years or older). The survey is programmed so that each respondent must complete all relevant items in the questionnaire to be included in the final data, with some items such as height, weight, and income providing an option to decline to answer. Potential respondents to the NHWS are recruited through an existing, general-purpose (ie, not health care-specific) web-based consumer panel. The consumer panel recruits its panel members through opt-in e-mails, coregistration with panel partners, e-newsletter campaigns, banner placements, and affiliate networks. All panelists explicitly agree to be a panel member, register with the panel through a unique e-mail address, and complete an in-depth demographic registration profile. A stratified random sampling procedure, with strata by sex, age, and ethnicity, was implemented to ensure that the demographic composition of the NHWS sample is representative of the US adult population. Comparisons between NHWS and other established sources (U.S. Census, National Health Interview Survey, National Health and Nutrition Examination Survey, etc) have been published previously.32 The 2011 NHWS was reviewed and approved by Essex Institutional Review Board (Lebanon, NJ); no review was sought for the current analysis of existing data. Respondents were told that the purpose of the survey was to collect information about their experience with health and health care, and they received points that could be redeemed for merchandise with the survey panel for their participation. As the focus of this study is the relationship between asthma control and health outcomes and health-related work impairment, the following inclusion criteria were adopted (all assessed through
JOEM r Volume 56, Number 4, April 2014 Copyright © 2014 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
425
JOEM r Volume 56, Number 4, April 2014
Vietri et al
self-report): physician diagnosis of asthma, current use of prescription medication for asthma, and current employment (fulltime, part-time, or self-employment). Asthma patients not taking a prescription medication for their asthma were excluded. Survey respondents who reported a physician diagnosis of chronic obstructive pulmonary disease, emphysema, or chronic bronchitis were also excluded from analysis to avoid misattributing chronic obstructive pulmonary disease-related burden to asthma.
MEASURES Asthma Control The Asthma Control Test (ACT) is a short, simple, self-report tool for identifying patients with poorly controlled asthma. It measures the elements of asthma control as defined by the National Heart, Lung, and Blood Institute. The ACT is an efficient, reliable, and valid method of measuring asthma control during the preceding 4 weeks.33 Scores range from 5 to 25, with scores below 20 indicating poor, uncontrolled, or less-than-well-controlled asthma. For clarity, we refer to workers with ACT scores above the cut point as “well controlled” and below the cut point as “poorly controlled.”
Demographics and Health Characteristics Several demographic and patient characteristic variables were included to describe well- and poorly controlled patients, as well as to identify variables to be controlled for when isolating the effect of asthma control on health outcomes. These variables included age, sex, race/ethnicity, marital status, education, annual household income, health insurance, body mass index, and Charlson comorbidity index.34
Outcomes
All analyses were conducted using SPSS version 19 (IBM Inc, Chicago, IL). An alpha error level of 0.05 (two-tailed) was used for all null-hypothesis tests. A series of bivariate analyses were conducted to compare patient demographics, health characteristics, and outcomes using chi-square for categorical variables and t tests for continuous variables. These analyses were followed by regression analysis to adjust the outcomes for their relationship with covariates. Specifically, generalized linear models incorporating a normal probability distribution and identity link function (ie, untransformed values) were conducted for each of the HRQoL metrics, whereas models predicting work productivity loss, activity impairment, and health care resource use specified negative binomial distributions with a log-link function to account for the positive skew of these data. In addition to the number of times the respondent used different types of health care, whether or not the respondent visited a traditional health care provider, went to the ER, or was hospitalized in the prior 6 months was modeled using logistic regression. Covariates included variables of theoretical importance to the outcomes as well as variables differing in bivariate analysis of asthma control, and entered into the models in a single step, and included age, race (white, black, Hispanic, Asian, or other), sex, annual household income (
Poor Asthma Control Among US Workers Health-Related Quality of Life, Work Impairment, and Health Care Use Jeffrey Vietri, PhD, Kate Burslem, MSc, and Jun Su, PhD
Objective: This study examined the impact of asthma control on healthrelated outcomes among employed US asthma sufferers treated with prescription medicines. Methods: Data from the 2011 National Health and Wellness Survey (N = 75,000) were used. The Asthma Control Test, validated measures of health-related quality of life, work productivity and activity impairment, and questions assessing health care use were included. Results: Of the 2026 employed asthma sufferers treated with prescription medicines included, 39.7% had Asthma Control Test scores indicating poorly controlled asthma. After adjusting for covariates, workers with poorly controlled asthma had worse health-related quality of life, work and activity impairment, and more health care use than those with well-controlled asthma. Conclusions: Poorly controlled asthma in employed patients treated with prescription medicines is common, and associated with negative health outcomes. Workers, employers, and payers could all benefit from improvements in asthma control.
A
sthma is a highly prevalent chronic inflammatory disorder that causes the airways to swell and narrow, leading to shortness of breath, coughing, and tightening of the chest.1,2 Asthma is common in the United States, affecting 9.5% of children and 7.7% of adults.3 Whereas no gold standard exists for defining asthma severity,4,5 severe asthma has been estimated to affect approximately 5 to 10% of those diagnosed with this condition.6–8 Asthma is associated with substantial costs, with direct medical costs in the United States estimated at $30 billion to $50 billion annually.9,10 A significant proportion of these costs is associated with emergency department visits, hospitalizations, and death, thus emphasizing the importance of appropriate management to maintain asthma control.11 Treatment guidelines have been established to promote effective clinical control through symptom reduction and prevention of exacerbations (asthma attacks), thus enabling sufferers to maintain normal functioning and activity.12 Although adequate control can be achieved in most patients through appropriate treatment and followup, many do not achieve adequate control and continue to suffer attacks.13,14 There are a number of patient and provider-based barriers to effective asthma control. These include poor patient adherence with treatment recommendations, inadequate treatment follow-up, as well as the impact of comorbid disease (eg, obesity15 ). For example, evidence suggests that despite the existence of treatment guidelines, some clinicians may be reluctant to adopt newer guidelines if they believe their current practice is effective.16 Furthermore, asthma is From the Health Outcomes Practice (Dr Vietri), Kantar Health, Princeton, NJ; and Boehringer Ingelheim Pharmaceuticals, Inc (Mr Burslem and Dr Su), Ridgefield, Conn. This work was conducted by Kantar Health and funded by Boehringer Ingelheim Pharmaceuticals, Inc (BIPI). Dr Vietri is an employee of Kantar Health and Dr Su and Mr Burslem are employees of BIPI. The authors declare no other conflicts of interest. Supplemental digital content is available for this article. Direct URL citation appears in the printed text and is provided in the HTML and PDF versions of this article on the journal’s Web site (www.joem.org). Address correspondence to: Jeffrey Vietri, PhD, Kantar Health, 1 Independence Way, Suite 220, Princeton, NJ 08540 ([email protected]). C 2014 by American College of Occupational and Environmental Copyright Medicine DOI: 10.1097/JOM.0000000000000123
a chronic condition that requires long-term management, and thus patient adherence to recommended treatment is often a challenge (for an overview, see Long17 ). A recent study by Cantrell and colleagues18 noted that, on the basis of US health insurance claims data, only 35% of asthma sufferers were considered compliant with treatment guidelines. Importantly, evidence suggests that inadequate asthma control can be associated with a host of negative outcomes, including impaired work productivity, impaired quality of life, increased rates of depression and anxiety, and greater health care costs and use of health care resources.14,19–28 A previous article by Williams and colleagues26 examined the impact of asthma control in a representative sample of US patients. They reported that those whose asthma was controlled had better health-related quality of life (HRQoL), lower health care resource utilization, and less work productivity impairment than those with uncontrolled asthma. The majority of patients experiencing asthma attacks are of working age,29,30 and a large proportion of patients are treated with prescription medications.31 The objective of this study was to evaluate the impact of asthma control on outcomes among employed asthma sufferers who are taking prescription medication for asthma treatment, since this may represent a significant burden on US employers, both in terms of health care costs and lost productivity.
METHODS Sample and Procedure
This study included data from the 2011 (N = 75,000) US National Health and Wellness Survey (NHWS). The NHWS is a self-administered, Internet-based questionnaire from a nationwide sample of adults (aged 18 years or older). The survey is programmed so that each respondent must complete all relevant items in the questionnaire to be included in the final data, with some items such as height, weight, and income providing an option to decline to answer. Potential respondents to the NHWS are recruited through an existing, general-purpose (ie, not health care-specific) web-based consumer panel. The consumer panel recruits its panel members through opt-in e-mails, coregistration with panel partners, e-newsletter campaigns, banner placements, and affiliate networks. All panelists explicitly agree to be a panel member, register with the panel through a unique e-mail address, and complete an in-depth demographic registration profile. A stratified random sampling procedure, with strata by sex, age, and ethnicity, was implemented to ensure that the demographic composition of the NHWS sample is representative of the US adult population. Comparisons between NHWS and other established sources (U.S. Census, National Health Interview Survey, National Health and Nutrition Examination Survey, etc) have been published previously.32 The 2011 NHWS was reviewed and approved by Essex Institutional Review Board (Lebanon, NJ); no review was sought for the current analysis of existing data. Respondents were told that the purpose of the survey was to collect information about their experience with health and health care, and they received points that could be redeemed for merchandise with the survey panel for their participation. As the focus of this study is the relationship between asthma control and health outcomes and health-related work impairment, the following inclusion criteria were adopted (all assessed through
JOEM r Volume 56, Number 4, April 2014 Copyright © 2014 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
425
JOEM r Volume 56, Number 4, April 2014
Vietri et al
self-report): physician diagnosis of asthma, current use of prescription medication for asthma, and current employment (fulltime, part-time, or self-employment). Asthma patients not taking a prescription medication for their asthma were excluded. Survey respondents who reported a physician diagnosis of chronic obstructive pulmonary disease, emphysema, or chronic bronchitis were also excluded from analysis to avoid misattributing chronic obstructive pulmonary disease-related burden to asthma.
MEASURES Asthma Control The Asthma Control Test (ACT) is a short, simple, self-report tool for identifying patients with poorly controlled asthma. It measures the elements of asthma control as defined by the National Heart, Lung, and Blood Institute. The ACT is an efficient, reliable, and valid method of measuring asthma control during the preceding 4 weeks.33 Scores range from 5 to 25, with scores below 20 indicating poor, uncontrolled, or less-than-well-controlled asthma. For clarity, we refer to workers with ACT scores above the cut point as “well controlled” and below the cut point as “poorly controlled.”
Demographics and Health Characteristics Several demographic and patient characteristic variables were included to describe well- and poorly controlled patients, as well as to identify variables to be controlled for when isolating the effect of asthma control on health outcomes. These variables included age, sex, race/ethnicity, marital status, education, annual household income, health insurance, body mass index, and Charlson comorbidity index.34
Outcomes
All analyses were conducted using SPSS version 19 (IBM Inc, Chicago, IL). An alpha error level of 0.05 (two-tailed) was used for all null-hypothesis tests. A series of bivariate analyses were conducted to compare patient demographics, health characteristics, and outcomes using chi-square for categorical variables and t tests for continuous variables. These analyses were followed by regression analysis to adjust the outcomes for their relationship with covariates. Specifically, generalized linear models incorporating a normal probability distribution and identity link function (ie, untransformed values) were conducted for each of the HRQoL metrics, whereas models predicting work productivity loss, activity impairment, and health care resource use specified negative binomial distributions with a log-link function to account for the positive skew of these data. In addition to the number of times the respondent used different types of health care, whether or not the respondent visited a traditional health care provider, went to the ER, or was hospitalized in the prior 6 months was modeled using logistic regression. Covariates included variables of theoretical importance to the outcomes as well as variables differing in bivariate analysis of asthma control, and entered into the models in a single step, and included age, race (white, black, Hispanic, Asian, or other), sex, annual household income (
