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Background and Objective: Metformin is a first-line treatment for patients with diabetes. Recent animal studies indicated that metformin can reduce airway inflammation. However, it remains unclear whether the use of metformin can help patients maintain asthma control. The purpose of this study was to evaluate the association between the use of metformin and asthma-related outcomes, which include asthma-related hospitalization, asthma-related emergency room visits and asthma exacerbation, among patients with concurrent asthma and diabetes., Methods: We conducted an 11-year (2001-2011) retrospective cohort study using the Taiwan National Health Insurance Research Database. Patients with concurrent asthma and diabetes were included. The date of the first observed prescription of metformin was defined as the index date. For each metformin user, two matched metformin non-users of the same age and gender were randomly selected. Patients were followed for 3 years to measure the occurrence of asthma-related outcomes. Multivariable logistic regression models were used to assess the association between metformin use and asthma-related outcomes., Results: Of 1332 patients with concurrent asthma and diabetes, 444 (33.3%) were metformin users. Compared with non-users, metformin users had a lower risk of asthma-related hospitalization (OR = 0.21, 95% CI: 0.07-0.63) and asthma exacerbation (OR = 0.39, 95% CI: 0.19-0.79)., Conclusion: The risk of asthma-related outcomes was lower for metformin users than non-users. Health-care providers should consider metformin as a treatment strategy for patients with concurrent asthma and diabetes., (© 2016 Asian Pacific Society of Respirology.)

Objectives: Very few studies have captured the differences in the outcomes of pediatric patients based on the patients' type of health insurance plan. The purpose of this retrospective cohort study was to examine the impact of the type of health insurance plan (public insurance vs. private insurance) on outcomes (health care utilization and medication adherence) in children with asthma., Methods: This retrospective cohort study analyzed Medicaid/commercial data from eight states licensed under Thomson Medstat. Subjects were 11,027 children with asthma (6435 enrolled in Medicaid and 4592 enrolled in a commercial health maintenance organization) who newly started asthma pharmacotherapy and were followed up for 12 months before and after the index anti-asthmatic medication fill. Data on health care utilization and medication adherence were examined to compare health care utilization-based outcomes. Quantile regression analysis was used to study medication adherence, and Poisson regression was used to determine health care utilization., Results: Patients with a private insurance plan had significantly higher medication adherence rates (p < .01) compared with those who had a Medicaid plan. Patients with Medicaid plans also were associated with 20% more inpatient hospitalizations and 48% increased odds of emergency department visits, but they had 42% fewer outpatient visits compared with those who had a private plan (all p < .05)., Conclusion: Children with asthma who are enrolled in Medicaid receive fairly comprehensive coverage of medical services, and thus further research is needed to determine the reasons for poor health care utilization-related outcomes in this population., (Published by Mosby, Inc.)

Objective: The purpose of this study was to evaluate the association between asthma status and the occurrence and length of work absences among the US working adults., Methods: A cross-sectional study was conducted using the 2008 Medical Expenditure Panel Survey (MEPS). Employed respondents between ages 18 and 55 years were included. The association between asthma status (whether respondents have asthma or not) and occurrence of absences and the length of time per absence was evaluated using a two-part model. A multivariate logistic regression as the first part of the model was to estimate the probability of being absent from work at least once during the observation period as a function of asthma status. A multivariate negative binomial regression as the second part of the model was used to assess whether the length of each absence from work was associated with asthma status among respondents who reported at least one absence from work. Sociodemographic, socioeconomic, employment-related, health status, and comorbidity variables were included in each model as covariates., Results: Of 12,161 respondents, 8.2% reported having asthma, which accounted for 10.4 million working adults in the United States in 2008. Employed adults with asthma were more likely to report having at least one absence from work compared to those without asthma in bivariate analyses (26.2% vs. 16.2%, p < .01). After adjusting for the number of comorbid chronic conditions and other covariates, there was no significant difference between having asthma and absenteeism among respondents (odds ratio (OR) = 1.31, 95% confidence interval (CI) = 0.99-1.72, rate ratio (RR) = 1.25, 95% CI = 0.91-1.72)., Conclusions: Overall burden of illness as measured by comorbidity indices and perceived health status, but not asthma alone, contributes to absenteeism as well as the number of days off during each occurrence among employed people. It is important for health services researchers to consider overall burden of illness when examining the association between a general outcome such as absence from work and specific conditions such as asthma.

Background: Not all patients with asthma adhere to their prescribed drug regimens. The Behavioral Model of Health Services Utilization, organized as predisposing, enabling, and need variables, may be useful in identifying variables related to adherent medication-taking behavior., Objective: To examine the relationship between predisposing, enabling, and need variables and self-reported adherence with asthma controller drugs., Methods: A secondary analysis was conducted from a cross-sectional study using survey and claims data obtained from adults with asthma enrolled in a managed care organization. Independent variables included predisposing (age, gender, race, years with asthma, number of comorbidities, health beliefs), enabling (income, number of metered-dose inhaler [MDI] instructors, inhaler technique, perceived physician access), and need (patient-perceived severity, symptom-derived severity, health-related quality of life). Adherence was measured using a 4 item questionnaire scored as the mean of the responses, with 5 denoting highest adherence. Multivariate regression analysis was used to identify variables with statistically significant relationships to self-reported adherence. Stepwise backward elimination was used, with the final model consisting of variables considered significant at p less than 0.05., Results: The 573 respondents (1270 packets sent; 45% response rate) were primarily white (89.5%) and female (71.0%), with an average age of 40.5 +/- 12.4 years (mean +/- SD) and average asthma duration of 18.3 +/- 14.2 years. The mean adherence scale score was 3.7 +/- 1.1, with 84.6% indicating some level of nonadherence (score <5). The final model had an adjusted R(2) of 0.26 and included 6 independent variables. Better adherence was associated with stronger beliefs in the benefits of treatment and trigger avoidance, greater perceived asthma severity, longer asthma duration, more MDI instructors, and higher scores on the Short-Form 36 mental component summary., Conclusions: Complex beliefs, perceptions, and experiences constitute the variables associated with adherent medication-taking behavior. Future longitudinal studies should include these variables to determine the predictive strength of the model.

Objectives: The purpose of this study was to observe the variation in the distribution of health-related quality of life and work performance scale scores based on using different methods of determining asthma severity., Methodology: Five methods of determining asthma severity were used, including three patient-derived measures (patient perceived severity or PPS; overall symptom-derived severity or OSS; and nocturnal symptom-severity or NSS); and 2 methods using retrospective pharmacy claims (reliever/oral steroid use or ROSU and multi-drug use or MDU). Three levels of severity were examined: mild, moderate, and severe, requiring condensing some severity categories of several methods. Data were obtained from a cross-sectional mail survey of 603 adults with asthma in a US managed care organization linked to pharmaceutical/medical claims data. Patient-reported outcomes included the Physical Component Summary Score (PCS) and the Mental Component Summary Score (MCS) of the SF-36, the summary score (AQLQ) of the Asthma Quality of Life Questionnaire, and the Work Performance Scale score (WPS) of the perceived work performance scale of the Functional Status Questionnaire. Analysis of variance (ANOVA) was used to examine each method's ability to distinguish between severity levels. Descriptive statistics were used to observe differences in scale scores between methods., Results: Within each method, significant severity effects (except MDU) were found for PCS, AQLQ, and WPS. In post-hoc analyses, mild-moderate and mild-severe comparisons were consistently significant (p < 0.05). In the cross-method analyses, method effects were found at all levels of severity for most scale scores with ranges increasing with increases in severity level. Within-method results were consistent with previous studies demonstrating a significant relationship between severity, health-related quality of life (HRQL) and work performance (WP). However, HRQL and WP scale scores varied by the method used to define severity., Conclusion: This variation should be considered when performing cross-study comparisons of burden of illness and treatment effects.

Background: There is a need for nonclinical measures in studies where objective clinical data used to determine asthma severity, such as spirometry and peak expiratory flow rate meter readings, are not available., Objective: To determine whether different methods of defining asthma severity provide different distributions of patients across the categories of mild, moderate, and severe asthma., Methods: Data were obtained from a mail survey and the database of a managed care organization located in Michigan. Seven methods of asthma severity that used either patient self-report or claims data were evaluated and divided into 3 categories: patient-perceived severity (1 method), symptom-derived severity (4 methods), and medication-derived severity (2 methods). To further evaluate the extent of the degree of agreement among the 7 severity methods, percent agreement and Cohen K scores were calculated., Results: Surveys were sent to 1,139 persons, and 603 responses were usable. Substantial differences exist in the number of patients in each severity level for different methods of determining asthma severity. The proportion of persons identified as having mild, moderate, and severe asthma ranged from 48% to 82%, 16% to 38%, and 2% to 33%, respectively. The percent agreement and Cohen kappa scores were generally low among the 7 methods., Conclusions: Due to variations caused by the method of measuring asthma severity, comparability among studies using different methods of classifying asthma severity is limited. Although a uniform evaluation of asthma severity is needed, the results of this study do not identify one preferable method. Rather, investigators should know the limitations of the methods used.

The purpose of this study was to examine relationships between patient- and disease-related variables and health-related quality of life (HQL). This cross-sectional study surveyed adults with asthma enrolled in a managed care organization (MCO). Data were obtained from a mailed questionnaire and the MCO's patient and claims databases. The Asthma Quality of Life Questionnaire (AQLQ) and the SF-36 instruments were used. The behavioral Model of Health Services Utilization was used to characterize independent variables and their relationships to HQL. Independent variables included predisposing (age, gender, education, race, number of comorbidities, years with asthma, social support, health-belief questions); enabling (income, number of metered dose inhaler (MDI) instructors, perceived inconvenience of accessing the physician); and illness level (perceived and symptom-derived asthma severity). Multivariate linear regression models were developed to examine the relationships between the independent variables and the domain and summary scores of the AQLQ and the SF-36. The survey response rate was 63% (n=603). for the AQLQ, symptom-derived severity perceived severity education level, and the health-belief factor Barriers were significant in all five models. Symptom-derived severity had consistently higher standardized regression coefficients than perceived severity Barriers had the highest coefficient in all but the Symptoms domain model. Number of Comorbidities was significant in all eight domain and two summary score SF-36 models. Symptom-derived and/or perceived severity were also significant in all but the Mental Health domain model. Other frequently significant variables included the health-belief factor Barriers and Yearly Household Income. When assessing HQL of a population, such as this group of patients with asthma, one must consider patient and disease variables that may influence the results.

The relationship between socioeconomic variables and the health-related quality of life (HQL) of children with asthma and their caregivers was examined. The Pediatric Asthma Quality of Life Questionnaire (PAQLQ) and Pediatric Asthma Caregivers Quality of Life Questionnaire (PACQLQ) were administered to 99 pediatric asthmatic patients and caregivers in two specialty clinics. Sociodemographic data was obtained from medical records and additional questions. The relationship between sociodemographic variables and HQL was determined using multiple linear regression. The mean patient age was 12.6+/-2.1 years, more were male and from a minority race. The mean age of caregivers was 41.2+/-8.5 years; most were female and were fom a minority race. Patients tended to rate their asthma severity as mild to moderate, while caregivers tended to rate patients in the moderate to severe category. Based on prescribed medications, most patients had mild to moderate asthma. Household income was consistently associated with patient-perceived HQL. Less consistent associations were seen with other variables. Household income and the caregiver's perception of asthma severity were associated with all caregiver HQL domains. It was concluded that household income was most consistently associated with the HQL of asthmatic pediatric patients and their caregivers.

Background: Asthma is a disease with physical symptoms that can impair a person's functioning to the point of interfering with school, work, and social activities., Objective: Describe how disease (asthma) and patient characteristics affect perceived work performance and absenteeism., Methods: Using a cross-sectional study design, 369 adults with asthma from a managed care organization responded to a mailed questionnaire which included a perceived work performance scale (WPS) and an item assessing absenteeism. Analysis consisted of psychometric testing of the scale (internal consistency and construct validity); trend observation of influence of perceived and symptom-derived severity on WPS and absenteeism distribution; and regression analysis to examine the relationship between patient/disease characteristics and the work-related outcomes., Results: The mean WPS score was 88.0 +/- 16.2 (of a possible 100), with a Cronbach's alpha of 0.79. Most respondents (84.7%) did not miss any work in the previous 4 weeks. WPS scores declined and the percentage of respondent absenteeism increased as perceived and symptom-derived severity worsened. The regression model for WPS produced an adjusted R2 of 0.32 and included the number of other illnesses, health beliefs, race, income, and perceived and symptom-derived asthma severity. The regression model for absenteeism included number of other illnesses, race, health beliefs, and symptom-derived severity. Perceived work performance and absenteeism are outcomes measures that are distinctive and complementary., Conclusions: Disease severity, race, income, and health beliefs also contribute and should be considered in health services research related to asthma.

Objective: To determine how well self-reported compliance with metered-dose inhalers (MDIs) agrees with compliance determined from pharmacy claims data. Additional analyses were conducted to establish phychmetric properties of the questionnaire., Methods: A cross-sectional survey was performed of all adult enrollees with asthma of a managed care organization. The overall return rate was 63.4% (696/1098). Patents with persistent asthma and at least one prescription claim for a controller MDI during the four months preceding the survey were included. Pharmacy claims data were used to calculate a compliance ratio. Self-reported compliance was based on a four-item questionnaire. The primary end points were the percent-agreement and the overall correlation between the two measures. The questionnaire's internal reliability and construct validity were assessed using Cronbach's alpha and Pearson's correlations, respectively. Mean item response scores for compliant patients were compared with scores of noncompliant patients using the Student's t-test., Results: One hundred questionnaire respondents met the study criteria. The mean +/- SD compliance ratio was 0.52+/-0.27, the mean +/- SD self-reported compliance score was 4.07+/-1.0. The overall percent agreement and correlation between self-reported compliance score and the compliance ratio were 75.5% and r = 0.348 (p = 0.01), respectively. The percent agreement was highest (85%) when noncompliant patients (by compliance ratio <0.8) reported being noncompliant (questionnaire score <5). Cronbach's alpha was 0.86., Conclusions: This study demonstrated a moderate correlation between self-reported asthma compliance and the compliance ratio determined using claims data. The questionnaire may be useful as a screening tool to detect noncompliant behavior in populations or individual patients with asthma.