Healthcare resource utilization, expenditures, and productivity in patients with asthma with and without allergies.

Objective: To compare healthcare resource utilization (HCRU), healthcare expenditures, and work productivity and activity impairment within a general asthma population with persistent asthma and evidence of allergy (PA-EA) and persistent asthma with no evidence of allergy (PA-NEA).Methods: We conducted a retrospective analysis of survey responses and claims from the Observational Study of Asthma Control and Outcomes (OSACO) study. Eligible patients with persistent asthma aged ≥12 years were sent four surveys over 15 months. Regression models were used to assess the association between: (1) PA-EA (defined as a positive response to a survey question about hay fever/seasonal allergies AND ≥1 diagnostic code for atopic conditions) and HCRU and expenditures; and (2) PA-EA and Work Productivity and Activity Impairment (WPAI)-Asthma questionnaire scores (vs. PA-NEA).Results: Adjusted data showed that, vs. PA-NEA (n = 312), patients with PA-EA (n = 971) incurred 1.34-times more all-cause prescriptions (95% confidence interval [CI], 1.20-1.48), $132.79 higher prescription costs (95% CI, $22.03-243.56), and $926.11 higher all-cause total healthcare costs (95% CI, $279.67-1572.54), per 4-month period. Patients with PA-EA were 4.1% less productive while working (95% CI, 3.75-4.48%) and experienced a 6.5% reduction in all activities (95% CI, 6.11-6.88%) vs. those with PA-NEA.Conclusions: Patients with PA-EA had greater HCRU, healthcare expenditures, and lower productivity compared with those patients with PA-NEA. These results highlight the burden of atopy in patients with persistent asthma and underscore the importance of allergic endotype identification for more vigilant disease management.

Impact of allergies on health-related quality of life in patients with asthma.

Objective: To estimate the health-related quality of life (HRQoL) and health utilities among asthma patients with and without comorbid allergies in a managed care population.Methods: This was a retrospective analysis of patient survey responses and pharmacy claims from the Observational Study of Asthma Control and Outcomes (OSACO). Patients ≥12 years-old with persistent asthma received four identical surveys between April-2011 and December-2012. The presence of allergy was identified by a positive response to a survey question about hay fever/seasonal allergies and ≥1 diagnosis-related ICD-9-CM code(s) for allergic conditions. HRQoL instruments included generic utility (EQ-5D-3L [including VAS]), asthma-specific utility (AQL-5D) and asthma-specific health status (Mini Asthma Quality of Life Questionnaire [MiniAQLQ]). Median regression was used for utility scores and Least Squares regression for MiniAQLQ, adjusting for sociodemographic characteristics and smoking.Results: Of the 2681 asthmatics who completed the first survey in the OSACO study, 971 had comorbid allergies. After adjusting for covariates, asthma patients with comorbid allergies had significantly lower MiniAQLQ scores than patients without allergies (-0.489 [95% CI -0.570, -0.409]; p < 0.01), with the greatest decrement/impairment observed for the environmental stimuli domain (-0.729 [95% CI -0.844, -0.613]; p < 0.01). Utility scores were also statistically significantly lower for asthma patients with comorbid allergies compared to those without allergies (EQ-5D, -0.031 [95% CI -0.047, -0.015]; AQL-5D, -0.036 [95% CI -0.042, -0.029]; p < 0.01 each).Conclusions: The presence of allergies with persistent asthma is associated with a significant deleterious impact on several different measures of HRQoL.

Medication use and indicators of poor asthma control in patients with and without allergies.

Background: Approximately two-thirds of people with asthma have some evidence of allergy; their condition differs from nonallergic asthma in terms of predominant symptoms and clinical outcomes. Objective: To compare asthma control and medication use among patients with persistent asthma with evidence of allergy (PA-EA) and patients with persistent asthma with no evidence of allergy (PA-NEA). Methods: A retrospective analysis of survey responses and medication claims data from the Observational Study of Asthma Control and Outcomes study, a prospective survey linked to retrospective claims-based analysis of patients ages ≥ 12 years with persistent asthma in a U.S. health maintenance organization. Evidence of allergy was defined as both a positive response to a survey question about hay fever and/or seasonal allergies and one or more medical diagnostic codes for atopic conditions. Regression models were used to compare asthma control (Asthma Control Questionnaire [ACQ] scores) and asthma medication use between PA-EA and PA-NEA. Results: Adjusted data showed that, versus the patients with PA-NEA (n = 312), patients with PA-EA (n = 971) had higher (worse) 5-item and 6-item ACQ (ACQ-5 and ACQ-6) scores (by 0.34 [95% confidence interval {CI}, 0.24-0.44]; and 0.31 [95% CI, 0.21-0.40], respectively), were more likely to have poorly controlled asthma (ACQ-5 score ≥ 1.5: odds ratio 3.37 [95% CI, 2.07-5.50]; ACQ-6 score ≥ 1.5: odds ratio 3.46 [95% CI, 2.13-5.62]) and less likely to have well-controlled asthma (ACQ-5 score ≤ 0.75: odds ratio 0.21 [95% CI, 0.13-0.34]; ACQ-6 score ≤ 0.75: odds ratio 0.21 [95% CI, 0.13-0.35]). Patients with PA-EA also had greater asthma medication use, most notably 2.5 times more prescriptions of high-dose inhaled corticosteroid in a 4-month period (95% CI, 1.21-5.16) and 16.15 times higher odds of chronic oral corticosteroid use (95% CI, 1.50-174.09) versus PA-NEA. Conclusion: The patients with PA-EA versus PA-NEA had worse asthma control and greater medication use. These patients may need more vigilant clinical oversight and treatment management to ensure adequate asthma control.

Oral corticosteroid exposure and adverse effects in asthmatic patients.

BACKGROUND: Significant adverse effects (AEs) have been associated with continuous exposure to oral corticosteroids (OCSs). The potential association with intermittent exposure is unknown. OBJECTIVE: We sought to assess the association between OCSs and AEs based on the number of OCS prescriptions. METHODS: This was a retrospective cohort study of asthmatic patients 18 years and older in the 2000-2014 MarketScan data set. Propensity score matching was used at baseline (12 months before the index date: first OCS use). Logistic regression was used to examine the association between OCSs and new incident AEs (either combined or individual) controlling for covariates. Follow-up continued for 24 months minimum and 10 years maximum after the index date. RESULTS: There were 72,063 and 156,373 subjects in the OCS and no OCS cohorts, respectively. Subjects taking 4 or more OCS (1-3) prescriptions within the year had 1.29 (1.04) times the odds of experiencing a new AE within the year. Each year of exposure to 4 or more OCS prescriptions (current and past) resulted in 1.20 times the odds of having an AE in the current year. Exposure to 4 or more prescriptions was associated with significantly greater odds of AEs for osteoporosis, hypertension, obesity, type 2 diabetes, gastrointestinal ulcers/bleeds, fractures, and cataracts (odds, 1.21-1.44 depending on the AE). CONCLUSION: Although previous research has documented the deleterious effect of continuous OCS exposure in patients with severe asthma, our results suggest that each OCS prescription might result in a cumulative burden on current and future health regardless of dose and duration. OCS-sparing strategies are extremely important to improve patient outcomes.

Estimating asthma control questionnaire (ACQ) scores from claims data.

BACKGROUND: Asthma control is the main focus of treatment guidelines. Valid instruments such as the Asthma Control Questionnaire (ACQ) require prospective survey. These surveys may be challenging for large population health applications. OBJECTIVE: To develop an algorithm for estimating ACQ-5 scores from commonly available claims data. METHODS: Data was derived from four prospective surveys including the ACQ-5 combined with retrospective claims of Kaiser Permanente of Colorado (KPCO) patients. The statistical approach consisted of derivation and validation of a prediction algorithm including medical and pharmacy claims data using stepwise regression elimination. Validation was conducted by estimating mean squared error (MSE) and mean absolute error (MAE) in one hundred split-sample iterations. Ordinary least squares (OLS), Tobit and Median regression were used. RESULTS: There were 2,657 individuals with valid ACQ-5 scores, claims and eligibility at baseline. The following had statistically significant associations with ACQ-5 scores: gender, use of oral corticosteroids and short-acting beta agonists, the number of asthma drug classes, and emergency and outpatient visits. Average MSE and MAE were similar for the estimation and validation samples. CONCLUSION: This research provides preliminary results of the feasibility of predicting ACQ-5 scores using commonly available medical and pharmacy claims data. The resulting algorithm may facilitate public health and population level analyses of asthma control. Future studies in different populations will be important to validate the algorithm.

Measuring the cost of poor asthma control and exacerbations.

BACKGROUND: Previous studies have shown an association between cost and poor asthma control. However, longitudinal studies of general populations are lacking. OBJECTIVE: To examine the cost of poor asthma control and exacerbations across a broad spectrum of asthma patients. METHODS: The Observational Study of Asthma Control and Outcomes (OSACO) was a prospective survey of persistent asthma patients in Kaiser Colorado in 2011-2012. Patients received a survey 3 times in one year, which included the Asthma Control Questionnaire (ACQ) and questions on exacerbations. Self-reported exacerbations were compared to actual oral corticosteroid (OCS) use. Regression analyses examined the association of control (ACQ-5 scores) and exacerbations with healthcare expenditures, controlling for sociodemographics and smoking. Analyses of expenditures used Generalized Linear Models (GLM) with log-link. RESULTS: 2681 individuals completed at least one survey; 1799 completed all three. ACQ-5 scores were associated with higher all-cause and asthma-specific expenditures across all categories of costs (medical, outpatient, ER, pharmacy) except for inpatient expenditures. Each 1-point increase in the ACQ-5 score (i.e., worse control) was associated with a corresponding increase in all-cause annual healthcare and asthma-specific expenditures of $1443 and $927 ($US 2013). Asthma exacerbations with documented OCS use were associated with an increase of $3014 and $1626 over 4 months, while self-reported exacerbations were $713 and $506. CONCLUSION: Results demonstrate that poor asthma control and exacerbations are strongly associated with higher healthcare expenditures. Results also confirm that collection of validated measures of control such as the ACQ-5 may provide valuable information toward improving clinical and economic outcomes.

Health-related quality of life associated with systemic corticosteroids.

BACKGROUND: Systemic corticosteroids (SCS) are commonly used but are associated with adverse effects. Given their prevalent use, the potential impact of SCS use on health-related quality of life (HRQoL) is important to characterize. OBJECTIVE: To assess the HRQoL of patients taking SCS. METHODS: The 2000-2003 Medical Expenditure Panel Survey was used to examine EQ-5D and SF-6D scores associated with SCS use in adults. The study sample was restricted to those with a condition for which SCS are prescribed. SCS use was categorized into three levels: none; 1-3; and ≥4 prescriptions per year. HRQoL scores were regressed on SCS use (1-3 or ≥4 annual prescriptions) controlling for age, gender, race, ethnicity, education, income category, geographic region, number of ER visits, number of outpatient visits, total number of chronic conditions (for which SCS are not used) and conditions for which SCS are clinically indicated. RESULTS: There were 54,856 individuals with no SCS exposure, 2245 with 1-3 and 624 with ≥4 annual SCS prescriptions. In adjusted analyses, use of ≥4 annual SCS prescriptions appeared to be associated with significantly lower EQ-5D (US), EQ-5D (UK), SF-6D and EQ-5D VAS scores compared to no exposure: -0.032, -0.047, -0.036, and -7.58. CONCLUSION: While SCS are efficacious and widely used for numerous conditions, results suggest that their use may be associated with a substantial deleterious impact on HRQoL. This potential negative effect should be considered in balance with the cost and efficacy of comparable treatments.

EQ-5D Scores for Diabetes-Related Comorbidities.

BACKGROUND: A single-source catalogue of nationally representative EuroQol five-dimensional questionnaire (EQ-5D) scores for chronic conditions in the United States and the United Kingdom from the Medical Expenditure Panel Survey (MEPS) has been published and has been used extensively for public health and cost-effectiveness modeling. OBJECTIVES: To estimate EQ-5D scores for diabetes-related chronic conditions that are consistent with the previous catalogue. METHODS: The MEPS is a nationally representative survey of the US civilian population. EQ-5D-3L questionnaire responses were mapped from short-form 12 health survey responses in 2000 to 2011 MEPS data using multinomial logistic regression. Country-specific tariffs were applied to the mapped EQ-5D responses for the United Kingdom, the United States, France, and Spain. EQ-5D scores were regressed on diabetes-related comorbidities controlling for sociodemographic characteristics, body mass index, and comorbidity using robust (median) regression. Methods were consistent with the previously published catalogue of EQ-5D scores for the United States. RESULTS: There were 20,705 individuals with diabetes and a valid mapped EQ-5D score in the 2000 to 2011 MEPS data. Unadjusted mapped EQ-5D scores for individuals with diabetes varied by country-specific tariff from 0.70 (France) to 0.79 (United States). Regression results reflecting marginal disutility estimates for EQ-5D scores are provided for 17 diabetes-related comorbidities and body mass index categories for US, UK, French, and Spanish tariffs. CONCLUSIONS: The estimates provided in this research may be useful for analysts attempting to model the impact of diabetes and diabetes-related comorbid conditions on utility. They are derived from a single-source, nationally representative population and augment the existing "off-the-shelf" catalogue of EQ-5D scores for chronic conditions.

Exploring asthma control cutoffs and economic outcomes using the Asthma Control Questionnaire.

BACKGROUND: Understanding the effect of worsening asthma control on expenditures and health resource utilization (HRU) is important. OBJECTIVE: To explore the association of economic outcomes with asthma control cutoffs and longitudinal changes on the Asthma Control Questionnaire 5 (ACQ-5). METHODS: The Observational Study of Asthma Control and Outcomes was a survey of patients with persistent asthma who were patients of Kaiser Colorado, including claims-based HRU. Patients completed the ACQ-5 three times during 1 year between April 2011 and June 2012. The ACQ-5 cutoffs that indicated control were assessed in cross-sectional analyses. Longitudinal changes in control were explored: controlled (ACQ-5 score <0.75), indeterminate (ACQ-5 score 0.75 to <1.5), not well controlled (ACQ-5 score 1.5 to <3.0), and very poorly controlled (ACQ-5 score ≥3.0). Analyses used generalized linear models with log link (expenditures) and negative binomial regression (HRU). RESULTS: There were 6,666 completed surveys (1,799 individuals completed all 3 survey waves). In the cross-sectional analyses, compared with an ACQ-5 score less than 0.5, individuals with ACQ-5 scores of 4 to 4.5 incurred 7.2 times the number of oral corticosteroid prescriptions, 4.3 times the number of emergency department visits, 6 times the number of inpatient visits, 10.4 times the number of asthma-specific emergency department visits, 4.58 times the number of asthma-specific inpatient visits, and $2,892 more in all-cause and $1,877 in asthma-specific expenditures during 4 months. In the longitudinal change analyses, individuals who improved from an ACQ-5 of 3.0 or greater to less than 0.75 incurred $6,023 less in asthma-specific expenditures during 4 months than those remaining at an ACQ-5 score of 3.0 or higher. CONCLUSION: Results provide preliminary economic data on possible control cutoffs for the ACQ-5. Improving asthma control over time may result in significant savings that may justify financial investments designed to improve control.

Measurement of utility in asthma: evidence indicating that generic instruments may miss clinically important changes.

BACKGROUND: Accurate assessment of preference-based health-related quality of life is important in determining the value of asthma interventions. OBJECTIVE: To examine the sensitivity and responsiveness of the EQ-5D and the AQL-5D to differences in asthma control measured by the Asthma Control Questionnaire (ACQ-5). METHODS: The Observational Study of Asthma Control and Outcomes was a prospective survey of persistent asthma patients ≥12 years old in Kaiser Colorado. Patients received a survey three times in 1 year, including the ACQ-5, AQL-5D and EQ-5D-3L (including VAS). Censored Least Absolute Deviations (CLAD) and logistic regression were used, controlling for sociodemographics and smoking. RESULTS: There were 6666 completed surveys (1799 individuals completed all three survey waves). After controlling for covariates, each one-point increase in ACQ-5 was associated with a decrease of 0.066, 0.058, 0.074 and 6.12 in EQ-5D(US), EQ-5D(UK), AQL-5D and VAS scores. Uncontrolled asthma (ACQ-5 > 1.5) was associated with a decrease of 0.15, 0.17, 0.11 and 10, respectively (vs. ACQ ≤ 1.5). AQL-5D scores were statistically significantly different across categories of ACQ-5 scores of 0.5 (the minimum clinically important difference [MCID]), while EQ-5D scores were not significant across most categories. The AQL-5D appeared more robust to changes in control over time (responsiveness) compared to EQ-5D-3L. CONCLUSION: The AQL-5D appears more responsive to changes in asthma control over time and more sensitive to detecting differences corresponding to the ACQ-5 MCID than the EQ-5D-3L. Using the EQ-5D-3L without an asthma-specific measure such as the AQL-5D may miss clinically important changes in asthma control.

Outcomes before and after treatment escalation to Global Initiative for Asthma steps 4 and 5 in severe asthma.

BACKGROUND: Little is known about health outcomes in severe asthma reflected by Global Initiative for Asthma steps 4 and 5. OBJECTIVE: To analyze control, risk, economic, and health resource use (HRU) outcomes associated with treatment escalation to Global Initiative for Asthma steps 4 and 5. METHODS: This was a before-vs-after retrospective cohort study of patients (12-75 years old) with asthma newly initiated to omalizumab, high-intensity corticosteroids (HICS; ≥1,000 µg/day of inhaled fluticasone equivalent or oral prednisone), or high-dose inhaled corticosteroid (HDICS; ≥500 to <1,000 µg/day of fluticasone equivalent) using 2002 to 2011 MarketScan data. Poisson regression was used to model HRU outcomes; Tobit regression was used to model medical expenditures. RESULTS: Of 19,227 patients, 856 initiated omalizumab, 6,926 initiated HICS, and 11,445 initiated HDICS. Use of ß-agonist increased for the HDICS and HICS cohorts and decreased for the omalizumab cohort; acute care visits and oral corticosteroid use decreased during follow-up for the HDICS and omalizumab cohorts. Annual health care expenditures, polypharmacy burden, and outpatient visits were high for all cohorts and increased in the follow-up year (baseline to follow-up; general health care expenditures: omalizumab $14,071 to $34,887, HICS $12,030 to $15,557, HDICS $7,570 to $9,826; annual number of asthma prescriptions: omalizumab 11.74 to 19.46, HICS 7.8 to 12.44, HDICS 5.17 to 9.69; outpatient visits: omalizumab 26.79 to 34.06, HICS 18.78 to 21.37, HDICS 15.06 to 16.64). CONCLUSION: Omalizumab use was associated with improvements in risk and control accompanied by large increases in expenditures per HRU. Patients on HDICS and HICS showed improvements in risk but worsening control and increased expenditures per HRU. Innovations in disease management and available treatment options are needed to more optimally achieve treatment goals.

Characterizing the severe asthma population in the United States: claims-based analysis of three treatment cohorts in the year prior to treatment escalation.

OBJECTIVES: Little is known about the disposition of severe patients prior to treatment escalation. To classify patients by treatment step using pharmacy data and describe their economic and healthcare utilization, insurance status, and sociodemographic characteristics in the year prior to escalation to Global Initiative for Asthma (GINA) steps 4 and 5. METHODS: This was a retrospective claims cohort study of asthma patients (age 12-75 years) newly initiated on "stable therapy" (three consecutive months of therapy) with omalizumab, high intensity corticosteroids (HICS; ≥1000 µg/d inhaled fluticasone equivalent or oral prednisone), or high-dose inhaled corticosteroid (HDICS; ≥500-<1000 µg/d fluticasone equivalent) from 2002 to 2011. Other asthma treatments were compared as a reference. RESULTS: Of 25,297 patients, 856 initiated omalizumab, 6926 initiated HICS, and 11,445 initiated HDICS. In the year prior to treatment escalation to omalizumab, HICS, and HDICS, respectively, individuals had high annual mean medical expenditures ($14,071, $12,030, and $7570), utilization (27 outpatient and 10 specialty care visits; 19 outpatient and three specialty; 15 outpatient and two specialty), asthma-related prescription drugs (11.74, 7.8, and 5.17) and chronic comorbidities (2.68, 2.67, and 2.19). Prior to omalizumab treatment, patients were more likely to be salaried, full-time employees with commercial PPO/POS insurance. CONCLUSIONS: Prior to escalating treatment to GINA steps 4 and 5, individuals experienced significant annual medical expenditures, healthcare resource utilization and polypharmacy burden, which may reflect poorly controlled asthma and the need to escalate treatment. Medical claims data and utilization-based measures may be helpful in classifying individuals by GINA treatment step.

Asthma control in the United States, 2008-2010: indicators of poor asthma control.

BACKGROUND: An estimated 23 million Americans have asthma, of whom at least 12 million experience an asthma exacerbation every year. Clinical practice guidelines focus on asthma control, with an emphasis on reducing both impairment and risk. OBJECTIVE: We sought to explore broad patterns of asthma prevalence, self-reported medication use, and indicators of control in a nationally representative sample. METHODS: The 2008, 2009, and 2010 Medical Expenditure Panel Surveys were used to examine the national prevalence of self-reported asthma, trends in medication use, and demographic characteristics of asthmatic patients. History of lifetime asthma and current diagnosis were ascertained based on self-report. Asthma management and control were examined by using patient-reported medication use. RESULTS: Of the 102,544 subjects asked about an asthma diagnosis, 9,782 reported lifetime asthma, and 8,837 reported current asthma. Five thousand five subjects (4.8% of the population) reported experiencing an asthma exacerbation in the previous year. Four thousand five hundred twenty-one subjects used a quick-relief inhaler for asthma symptoms, and 14.6% used more than 3 canisters of this type of medication in the past 3 months. Of this group, 60% were using daily long-term control medication but still required significant use of quick-relief inhalers, whereas 28% had never used long-term control medication. Of those who had a recent exacerbation, 29% were using daily preventive medication, whereas 54% had never used long-term control medication. CONCLUSIONS: Improvement of asthma control continues to be a US public health concern. Results suggest suboptimal asthma control with underuse of long-term control medications, overuse of quick-relief inhalers, and a significant number of self-reported asthma exacerbations.

The relationship between asthma, asthma control and economic outcomes in the United States.

OBJECTIVE: Asthma, a serious chronic lung disease affecting approximately 26 million Americans, remains clinical and economic burdens on the healthcare system. Although associations between uncontrolled asthma and poor health outcomes is known, the extent of this impact of uncontrolled asthma on economic outcomes in the United States (US) is unknown. We sought to determine the relationship between asthma, asthma control and economic outcomes in the US. METHODS: The 2008-2010 Medical Expenditure Panel Surveys were used to estimate the impact of uncontrolled asthma (asthma-related emergency department [ED] visit, use of >3 canisters of quick-relief inhaler in past 3 months or asthma attack in past 12 months) on medical expenditures, utilization and productivity. Estimates were generated using multivariate regression controlling for sociodemographics and comorbidity. RESULTS: Medical expenditures attributable to asthma were up to $4423 greater for those with markers of uncontrolled asthma compared with those who did not have asthma. Frequency of hospital discharges were up to 4.6-fold greater for those with uncontrolled asthma than those without asthma (p < 0.01), while all others with asthma did not have significantly more discharges. ED visits were up to 1.8-fold greater for those with uncontrolled asthma compared with those without asthma (p < 0.01). Productivity was significantly (p < 0.01) decreased (more likely to be unemployed, more days absent from work and more activity limitations) for those with uncontrolled asthma. CONCLUSIONS: In recent national data, individuals with asthma and markers of uncontrolled asthma had higher medical expenditures, greater utilization and decreased productivity.

Asthma in USA: its impact on health-related quality of life.

OBJECTIVES: Given the growing prevalence of asthma in USA, it is important to understand its national burden from the patient's perspective. The objective of this research is to examine the national burden of asthma and poor asthma control on health function, health perception and preference-based health-related quality of life (HRQL). METHODS: The Medical Expenditure Panel Survey (MEPS), a nationally representative survey, was used to estimate the impact of asthma and indicators of poor asthma control on health function, self-rated health perception and preference-based HRQL using multivariate regression methods controlling for socioeconomic, clinical and demographic characteristics. Two HRQL instruments were used: SF-12v2 Physical Component Scale (PCS-12) and Mental Component Scale (MCS-12); EQ-5D-3L index and visual analogue scale (VAS). Two multivariate regression methods were used, Censored Least Absolute Deviation [EQ-5D-3L and VAS (due to censoring)] and Ordinary Least Squares (OLS) (PCS-12 and MCS-12). RESULTS: After controlling for covariates, asthma resulted in a statistically significant reduction in preference-based HRQL, health perception and physical and mental function (EQ-5D -0.023; VAS -2.21; PCS-12 -2.36; MCS-12 -0.96). Likewise, experiencing an exacerbation in the previous year and using more than three canisters of quick-relief medication in the previous 3 months were both associated with a statistically significant and clinically meaningful reduction in all four measures. CONCLUSIONS: Asthma itself and especially indicators of poor asthma control were associated with a deleterious effect on health function, preference-based HRQL and self-perceived health status. Given the prevalence of asthma, poorly controlled asthma constitutes a significant national burden in USA.

The burden of adult asthma in the United States: evidence from the Medical Expenditure Panel Survey.

BACKGROUND: It is important to have an accurate picture of the sources and extent of medical expenditures and productivity loss to understand the nature and scope of the burden of asthma in the United States (US). OBJECTIVE: The current study aims to provide recent nationally representative estimates of direct and productivity-related costs attributable to asthma in adults in the US. METHODS: The 2003 and 2005 Medical Expenditure Panel Surveys were used to estimate the effect of asthma on medical expenditures, use, productivity, and chronic comorbidity among adults (≥ 18 years). Productivity-related outcome variables included employment, annual wages, missed work days, days spent sick in bed, and activity limitations. Multivariate regression was conducted, controlling for sociodemographics and comorbidity. RESULTS: Of 44,795 adults, 1,935 reported an encounter for asthma [corrected]. Compared with those without, subjects with asthma were significantly less likely to be employed (odds ratio, 0.78), spent 1.4 more days sick in bed annually, and were significantly more likely to have activity limitations or to be unable to work. Adults with asthma incurred an additional $1,907 (2008 US dollars) annually and experienced higher health care use and comorbidity. The total national medical expenditure attributable to adult asthma was $18 billion. Adults with asthma were more likely to be covered by Medicaid (30%) than the general adult population (10%). The largest contributors to medical expenditures for adults with asthma were prescription drugs, followed by inpatient hospitalizations and home health care. CONCLUSIONS: In recent national data adult asthma is associated with a significant deleterious effect on direct and indirect costs in the US.

Complications and Health Care Resource Utilization Associated with Systemic Corticosteroids in Children and Adolescents with Persistent Asthma.

BACKGROUND: Limited comparative data are available on the impact of systemic corticosteroid (SCS) use in children and adolescents. OBJECTIVE: To determine if asthmatic children and adolescents treated with SCS have a higher likelihood of developing complications versus those not receiving SCS and to examine health care resource utilization (HCRU) in this population. METHODS: A retrospective study of data from children and adolescents with persistent asthma retrieved from the MarketScan database, a large US health claims data set, for the period 2000 to 2017 was performed. Propensity score matching was used to pair patients in the SCS and control cohorts. For complications, SCS subgroups (≥4 or 1-3 annual prescriptions) were compared with asthmatic controls without SCS using logistic regression, and for HCRU, cohorts were compared using negative binomial regression. RESULTS: A total of 67,081 patients were included (SCS: 23,898; control: 43,183). The odds of having a complication were 2.9 (95% confidence interval [CI], 2.5-3.2; P < .001) and 1.6 (95% CI, 1.6-1.7; P < .001) times higher in the ≥4 and 1 to 3 SCS groups, respectively, in the first year of follow-up versus controls. For asthma-related hospitalizations, the incidence rate ratio (IRR) was 6.9 (95% CI, 5.6-8.6) and 3.1 (95% CI, 2.8-3.4) times greater in the ≥4 SCS and 1 to 3 SCS groups, respectively, versus controls; for asthma-related emergency department visits, IRR was 5.0 (95% CI, 4.4-5.6) and 2.9 (95% CI, 2.7-3.0) times greater, respectively, versus controls (all P < .01). CONCLUSION: Children and adolescents receiving SCS for persistent asthma have an increased risk of developing complications and have greater HCRU in the first year of follow-up versus those without SCS exposure.

Association Between Pulmonary Function and Asthma Symptoms.

BACKGROUND: FEV1 as a percentage of predicted (FEV1%pred) is commonly measured in asthma clinical studies; however, reports vary on its association with asthma control instruments evaluating symptoms. OBJECTIVE: Assess the association between FEV1%pred and Asthma Control Questionnaire (ACQ) scores in a managed-care population with persistent asthma. METHODS: Retrospective analysis of survey responses and spirometry results of patients (aged ≥12 years) with persistent asthma from the Observational Study of Asthma Control and Outcomes was done. Eligible patients received 4 identical surveys including the 5-item ACQ (ACQ-5)/6-item ACQ (ACQ-6) and completed spirometry in parallel. Longitudinal analyses, comparisons of change over time, and fixed- and random-effects regression analyses were conducted, with/without adjustment for covariates. RESULTS: There were 1748 survey responses with valid spirometry results. In unadjusted models, coefficients for ACQ-5/ACQ-6 scores were not statistically significant and coefficient of determination (R2) was low (0.03). When adjusted for covariates, ACQ-5 and ACQ-6 scores were significantly associated with FEV1%pred (P < .001) and R2 increased to 0.11 and 0.12, respectively. In adjusted models, every 1-point increase in ACQ-5 and ACQ-6 scores was associated with a 1.7% and 1.9% decrease, respectively, in FEV1%pred. Change in FEV1%pred and change in ACQ-5/ACQ-6 scores were not significantly associated in regressions with/without covariates. CONCLUSIONS: The weak and statistically insignificant association between FEV1%pred and ACQ-5/ACQ-6 scores in unadjusted models suggests a high degree of unexplained variation between these measures. Results support the use of both symptoms and pulmonary function, rather than relying on one measure alone, to assess asthma control in clinical care and outcomes studies.

The impact of co-morbidity burden on preference-based health-related quality of life in the United States.

BACKGROUND: Many statistical analyses, clinical trials and cost-utility analyses designed to measure the impact of a particular disease on utility scores often overlook the important influence of co-morbidity burden. OBJECTIVES: This study aims to examine the impact of co-morbidity burden on EQ-5D index scores in a nationally representative sample of the US. METHODS: The pooled 2001 and 2003 Medical Expenditure Panel Survey was used. The total number of chronic conditions for each individual was calculated based on Clinical Classification Categories codes. Spline regression was used to identify nonlinear age effects: individuals were separated into four quartiles based on age. Censored least absolute deviation was used to regress EQ-5D index scores on age and chronic co-morbidity, controlling for income, gender, race, ethnicity, education, physical activity and smoking status. Interactions between age and chronic conditions were also explored. RESULTS: The coefficients for chronic co-morbidities were highly statistically significant with large magnitudes for those with two or more chronic conditions (coefficient two chronic conditions=-0.16; coefficient nine chronic conditions=-0.28). After controlling for chronic co-morbidities and other confounders, age was not statistically significant except for those aged>58 years and the magnitude of this coefficient was very small (coefficient aged>58 years=-0.0006). The interactions between age and chronic co-morbidity were significant, but the deleterious impact of their interaction was largely dominated by the existence and number of chronic conditions. CONCLUSIONS: Chronic conditions have a significant deleterious impact on EQ-5D index scores that is much more pronounced than age and other sociodemographic and behavioural characteristics. Future analyses and cost-utility models should incorporate the impact of multiple morbidity.