The patient level cost of asthma in adults in south central Ontario. Pharmacy Medication Monitoring Program Advisory Board

Models for estimating and projecting global, regional and national prevalence and disease burden of asthma: a systematic review

Background

Statistical models are increasingly being used to estimate and project the prevalence and burden of asthma. Given substantial variations in these estimates, there is a need to critically assess the properties of these models and assess their transparency and reproducibility. We aimed to critically appraise the strengths, limitations and reproducibility of existing models for estimating and projecting the global, regional and national prevalence and burden of asthma.

Methods

We undertook a systematic review, which involved searching Medline, Embase, World Health Organization Library and Information Services (WHOLIS) and Web of Science from 1980 to 2017 for modelling studies. Two reviewers independently assessed the eligibility of studies for inclusion and then assessed their strengths, limitations and reproducibility using pre-defined quality criteria. Data were descriptively and narratively synthesised.

Results

We identified 108 eligible studies, which employed a total of 51 models: 42 models were used to derive national level estimates, two models for regional estimates, four models for global and regional estimates and three models for global, regional and national estimates. Ten models were used to estimate the prevalence of asthma, 27 models estimated the burden of asthma – including, health care service utilisation, disability-adjusted life years, mortality and direct and indirect costs of asthma – and 14 models estimated both the prevalence and burden of asthma. Logistic and linear regression models were most widely used for national estimates. Different versions of the DisMod-MR- Bayesian meta-regression models and Cause Of Death Ensemble model (CODEm) were predominantly used for global, regional and national estimates. Most models suffered from a number of methodological limitations – in particular, poor reporting, insufficient quality and lack of reproducibility.

Conclusions

Whilst global, regional and national estimates of asthma prevalence and burden continue to inform health policy and investment decisions on asthma, most models used to derive these estimates lack the required reproducibility. There is a need for better-constructed models for estimating and projecting the prevalence and disease burden of asthma and a related need for better reporting of models, and making data and code available to facilitate replication.

Clinical and economic burden of idiopathic pulmonary fibrosis in Quebec, Canada

Background

Idiopathic pulmonary fibrosis (IPF), although rare, is a severe and costly disease.

Objective

To estimate the clinical and economic burden of IPF over multiple years before and after diagnosis using comprehensive administrative databases for the province of Quebec, Canada.

Methods

Several administrative databases from Quebec, providing information on hospital care, community care, and pharmaceuticals, were linked over a 5-year period ending March 31, 2011, which was before approval of antifibrotic drugs in Canada. Prevalent and incident IPF cases were defined using International Classification Disease-10-CA codes and International Classification Disease-9-CM codes. We used a broad definition that excluded cases with subsequent diagnosis of other interstitial lung diseases and a narrow definition that required further diagnostic testing to confirm IPF diagnosis. Incident cases had an IPF code in a particular year without any IPF code in the 2 previous years. Health care resource utilization before and after the index diagnosis date was determined and costs calculated. Costs were expressed in 2016 Canadian dollars.

Results

Over 5-years, 10,579 (mean age: 76.4; 58% male) satisfied the broad definition of IPF and 8,683 (mean age: 74.5; 57% male) satisfied the narrow definition (82% of broad). Incidences of IPF overall were 25.8 and 21.7/100,000 population for broad and narrow definitions, respectively. Three-year survival was 40% and 37% in broad and narrow cohorts, respectively. For both cohorts, health care resource utilization and costs increased several years before diagnosis ($2,721 and $7,049/patient 5 years and 2 years prior to diagnosis using a broad definition, respectively) and remained elevated for multiple years post diagnosis ($12,978 and $8,267 at 2 and 3 years postdiagnosis).

Conclusion

Health care resource utilization and costs of IPF increase many years prior to diagnosis. Incorporating multiyear annual costs before and after diagnosis results in a higher estimate of the economic burden of IPF than previous studies using a 1-year time frame.

Health Care Utilization and Direct Costs in Mild, Moderate, and Severe Adult Asthma: A Descriptive Study Using the 2014 South Korean Health Insurance Database

PURPOSE

Although asthma exacerbation comprises a large burden of the total asthma-related costs, few studies have examined the frequency and cost of acute exacerbation according to asthma severity. This study investigated asthma-related health care utilization and costs according to the severity of asthma.

METHODS

We conducted a descriptive study using the national health insurance claims database between January 1 and December 31, 2014. We included adult patients with asthma (18 years of age and older) who had ≥2 claims with for an asthma diagnosis and were prescribed ≥1 asthma medications. They were classified into 3 asthma severity levels (level 1 = mild, level 2 = moderate, and level 3 = severe), based on individual medication prescriptions. Acute exacerbation was defined as having a corticosteroid burst, an emergency department visit, or hospitalization. Health care utilization, acute exacerbation, and direct costs associated with asthma were compared according to asthma severity levels.

FINDINGS

Of the 36,687 adult asthma patients, level 1 had the largest proportion of patients (81.2%), followed by level 2 (18.2%), and level 3 (0.6%). The average number of asthma-related outpatient visits was 4.5 for level 1, 7.2 for level 2, and 11.9 for level 3 (P < 0.01). The estimated asthma-related direct cost per patient was $174 for level 1, $634 for level 2, and $1635 for level 3 (P < 0.01). The number of patients who experienced acute exacerbation increased as asthma severity increased: level 1, 22.6%; level 2, 26.0%; and level 3, 48.7% (P < 0.01). Direct costs associated with asthma exacerbation dramatically increased and accounted for 15.1% of the total cost in level 1 patients, 19.5% in level 2 patients, and 40.8% in level 3 patients (P < 0.01).

IMPLICATIONS

The direct costs of acute exacerbation increased as asthma severity increased. In patients with severe asthma, acute exacerbation and the relative cost ratio in South Korea were higher than those in other countries. Proper management is required to avoid acute exacerbations and to reduce the burden of asthma, particularly in patients with severe asthma.

A Cross-Sectional Comparison of Direct Medical Care Costs among COPD and Asthma Patients Living in the Community in Northern Ireland

INTRODUCTION

Asthma and COPD are known to have significant health and economic consequences. Little is known about the costs of the latter in the UK. In this study we report the results of a comparison of the direct medical costs associated with COPD and asthma, where diagnoses are based on a robust prevalence study of a random sample of the Northern Ireland population.

METHODS

A two-stage survey was used to identify individuals with COPD and asthma. The diagnoses of asthma and COPD were based on patient history and lung function. Patients completed a detailed questionnaire covering healthcare utilization over the past 12 months, socioeconomic characteristics, impact of the disease on quality of life, and activities of daily living.

RESULTS

Forty-nine patients were diagnosed with COPD and 57 with asthma. Three asthma patients were excluded from the main analysis because they were thought to have atypical inpatient stays or other resource use. The mean direct healthcare cost for each COPD patient was estimated at pound171.69 ($US309; year 2000 value) per annum, significantly less than the average cost of asthma among the 54 analyzed of pound544.54 ($US980) [p < 0.05]. A correlation analysis revealed that among COPD patients, disease severity, defined by lung function, was a significant predictor of costs.

CONCLUSION

Community-based costs for asthma are greater than those for COPD; this may relate in part to a relative under-diagnosis of COPD (73.5% COPD vs 15.8% asthma). As anticipated, the cost of COPD increases as FEV(1) decreases. Further analysis will enable modeling of the cost consequences of both increased diagnosis and better management of COPD.

Cost-of-illness studies based on massive data: a prevalence-based, top-down regression approach

Despite the increasing availability of routine data, no analysis method has yet been presented for cost-of-illness (COI) studies based on massive data. We aim, first, to present such a method and, second, to assess the relevance of the associated gain in numerical efficiency. We propose a prevalence-based, top-down regression approach consisting of five steps: aggregating the data; fitting a generalized additive model (GAM); predicting costs via the fitted GAM; comparing predicted costs between prevalent and non-prevalent subjects; and quantifying the stochastic uncertainty via error propagation. To demonstrate the method, it was applied to aggregated data in the context of chronic lung disease to German sickness funds data (from 1999), covering over 7.3 million insured. To assess the gain in numerical efficiency, the computational time of the innovative approach has been compared with corresponding GAMs applied to simulated individual-level data. Furthermore, the probability of model failure was modeled via logistic regression. Applying the innovative method was reasonably fast (19 min). In contrast, regarding patient-level data, computational time increased disproportionately by sample size. Furthermore, using patient-level data was accompanied by a substantial risk of model failure (about 80 % for 6 million subjects). The gain in computational efficiency of the innovative COI method seems to be of practical relevance. Furthermore, it may yield more precise cost estimates.

The preventable burden of productivity loss due to suboptimal asthma control: a population-based study

BACKGROUND

Productivity loss is an overlooked aspect of the burden of chronic health conditions. While modern guidelines emphasize achieving clinical control in asthma management, few studies have reported on the relationship between asthma control and productivity loss. We calculated the productivity loss that can be avoided by achieving and maintaining clinical control in employed adults with asthma.

METHODS

We prospectively recruited a population-based random sample of adults with asthma in British Columbia, Canada. We measured productivity loss due to absenteeism and presenteeism using validated instruments, and ascertained asthma control according to the GINA (Global Initiative for Asthma) classification. We estimated the average gain in productivity for each individual if the individual’s asthma was controlled in the past week, by fitting two-part regression models associating asthma control and productivity loss, controlling for potential confounding variables.

RESULTS

The final sample included 300 employed adults (mean age, 47.9 years [SD 12.0]; 67.3% women). Of these, 49 (16.3%) reported absenteeism, and 137 (45.7%) reported presenteeism. Productivity loss due to presenteeism, but not absenteeism, was associated with asthma control. A person with uncontrolled asthma would avoid $184.80 (Canadian dollars [CAD]) in productivity loss by achieving clinical control during a week, CAD$167.50 (90.6%) of which would be due to presenteeism. The corresponding value was CAD$34.20 for partially controlled asthma and was not statistically significant.

CONCLUSIONS

Our results indicate that substantial gain in productivity can be obtained by achieving asthma control. Presenteeism is more responsive than absenteeism to asthma control, and, thus, is a more important source of preventable burden.

Using a knowledge translation framework to implement asthma clinical practice guidelines in primary care

Quality problem

International guidelines establish evidence-based standards for asthma care; however, recommendations are often not implemented and many patients do not meet control targets.

Initial assessment

Regional pilot data demonstrated a knowledge-to-practice gap.

Choice of solutions

We engineered health system change in a multi-step approach described by the Canadian Institutes of Health Research knowledge translation framework.

Implementation

Knowledge translation occurred at multiple levels: patient, practice and local health system. A regional administrative infrastructure and inter-disciplinary care teams were developed. The key project deliverable was a guideline-based interdisciplinary asthma management program. Six community organizations, 33 primary care physicians and 519 patients participated. The program operating cost was $290/patient.

Evaluation

Six guideline-based care elements were implemented, including spirometry measurement, asthma controller therapy, a written self-management action plan and general asthma education, including the inhaler device technique, role of medications and environmental control strategies in 93, 95, 86, 100, 97 and 87% of patients, respectively. Of the total patients 66% were adults, 61% were female, the mean age was 35.7 (SD = ±24.2) years. At baseline 42% had two or more symptoms beyond acceptable limits vs. 17% (P< 0.001) post-intervention; 71% reported urgent/emergent healthcare visits at baseline (2.94 visits/year) vs. 45% (1.45 visits/year) (P< 0.001); 39% reported absenteeism (5.0 days/year) vs. 19% (3.0 days/year) (P< 0.001). The mean follow-up interval was 22 (SD = ±7) months.

Lessons learned

A knowledge-translation framework can guide multi-level organizational change, facilitate asthma guideline implementation, and improve health outcomes in community primary care practices. Program costs are similar to those of diabetes programs. Program savings offset costs in a ratio of 2.1:1

Direct health care costs associated with asthma in British Columbia

BACKGROUND

A better understanding of health care costs associated with asthma would enable the estimation of the economic burden of this increasingly common disease.

OBJECTIVE

To determine the direct medical costs of asthma-related health care in British Columbia (BC).

METHODS

Administrative health care data from the BC Linked Health Database and PharmaNet database from 1996 to 2000 were analyzed for BC residents five to 55 years of age, including the billing information for physician visits, drug dispensations and hospital discharge records. A unit cost was assigned to physician/emergency department visits, and government reimbursement fees for prescribed medications were applied. The case mix method was used to calculate hospitalization costs. All costs were reported in inflation-adjusted 2006 Canadian dollars.

RESULTS

Asthma resulted in $41,858,610 in annual health care-related costs during the study period ($331 per patient-year). The major cost component was medications, which accounted for 63.9% of total costs, followed by physician visits (18.3%) and hospitalization (17.8%). When broader definitions of asthma-related hospitalizations and physician visits were used, total costs increased to $56,114,574 annually ($444 per patient-year). There was a statistically significant decrease in the annual per patient cost of hospitalizations (P<0.01) over the study period. Asthma was poorly controlled in 63.5% of patients, with this group being responsible for 94% of asthma-related resource use.

CONCLUSION

The economic burden of asthma is significant in BC, with the majority of the cost attributed to poor asthma control. Policy makers should investigate the reason for lack of proper asthma control and adjust their policies accordingly to improve asthma management.

(Correcting) misdiagnoses of asthma: a cost effectiveness analysis

BACKGROUND

The prevalence of physician-diagnosed-asthma has risen over the past three decades and misdiagnosis of asthma is potentially common.

OBJECTIVE

to determine whether a secondary-screening-program to establish a correct diagnosis of asthma in those who report a physician diagnosis of asthma is cost effective.

METHOD

Randomly selected physician-diagnosed-asthmatic subjects from 8 Canadian cities were studied with an extensive diagnostic algorithm to rule-in, or rule-out, a correct diagnosis of asthma. Subjects in whom the diagnosis of asthma was excluded were followed up for 6-months and data on asthma medications and heath care utilization was obtained. Economic analysis was performed to estimate the incremental lifetime costs associated with secondary screening of previously diagnosed asthmatic subjects. Analysis was from the perspective of the Canadian healthcare system and is reported in Canadian dollars.

RESULTS

Of 540 randomly selected patients with physician diagnosed asthma 150 (28%; 95%CI 19-37%) did not have asthma when objectively studied. 71% of these misdiagnosed patients were on some asthma medications. Incorporating the incremental cost of secondary-screening for the diagnosis of asthma, we found that the average cost savings per 100 individuals screened was $35,141 (95%CI $4,588-$69,278).

CONCLUSION

Cost savings primarily resulted from lifetime costs of medication use averted in those who had been misdiagnosed.

Economic burden of asthma: a systematic review

BACKGROUND

Asthma is associated with enormous healthcare expenditures that include both direct and indirect costs. It is also associated with the loss of future potential earnings related to both morbidity and mortality. The objective of the study is to determine the burden of disease costs associated with asthma.

METHODS

We performed a systematic search of MEDLINE, EMBASE, CINAHL, CDSR, OHE-HEED, and Web of Science Databases between 1966 and 2008.

RESULTS

Sixty-eight studies met the inclusion criteria. Hospitalization and medications were found to be the most important cost driver of direct costs. Work and school loss accounted for the greatest percentage of indirect costs. The cost of asthma was correlated with comorbidities, age, and disease severity.

CONCLUSION

Despite the availability of effective preventive therapy, costs associated with asthma are increasing. Strategies including education of patients and physicians, and regular follow-up are required to reduce the economic burden of asthma.

Asthma-related productivity losses in Alberta, Canada

OBJECTIVES

To estimate the number and cost of asthma-related productivity loss days due to absenteeism and presenteeism (at work but not fully functioning) in Alberta in 2005.

METHODS

Using data from the 2005 Canadian Community Health Survey, this study focused on people of working age (18-64 years), who reported having an asthma diagnosis. Total asthma-related disability days, including in-bed days and activity-restricted days, were estimated by multiplying the difference in the means of total disability days between asthmatics and nonasthmatics adjusted for sociodemographic characteristics and other health conditions by a multiple linear regression, with the number of asthmatics in the population. Number of productivity loss days was a sum between the number of in-bed days (absenteeism) and the number of activity-restricted days multiplied by a reduction in functional level (presenteeism), adjusted for five working days per week. Other data from Alberta or Canadian published literature, such as a reduction in functional level of 20%-30%, a labor participation rate of 73%, and an average wage of $158 per day in 2005, were also used for analyses.

RESULTS

The prevalence of asthma was estimated at 8.5% among approximately 2.1 million people of working age in Alberta in 2005. The difference in the means of total disability days between asthmatics and nonasthmatics was 0.487 (95% CI: 0.286-0.688) in a period of two weeks or 12.7 (7.5-17.9) in one year. With the reduction in functional level of 20%-30%, the number of asthma-related productivity loss days was estimated from 442 (259-624) to 533 (313-753) thousand, respectively. The corresponding cost was from $70 ($41-$99) to $84 ($49-$119) million. Of these, the presenteeism accounted for 42% to 52%.

CONCLUSIONS

The results suggest that an improvement in the controlling of asthma could have a significant economic impact in Alberta and that presenteeism plays an important role in asthma-related productivity losses and therefore employers should not only pay attention to absenteeism, but also to presenteeism to minimize productivity loss.

The weekly cost of nausea and vomiting of pregnancy for women calling the Toronto Motherisk Program

BACKGROUND

Nausea with or without vomiting of pregnancy (NVP) is the most common medical condition in pregnancy. NVP, even with mild symptoms, is associated with costs to society, patients, and the health care system.

OBJECTIVE

The main objective of this study was to estimate the total direct and indirect costs per woman-week associated with the onset of NVP in Canada from the perspective of society.

METHODS

A cost of illness study was performed to estimate the cost per woman-week associated with the onset of NVP in Canada, stratified according to the severity of NVP. Data were collected from 139 pregnant women, who called the Motherisk Program at the Hospital for Sick Children in Toronto. Results are reported in 2005 Canadian dollars.

RESULTS

From the perspective of society, the total cost per woman-week was $132 ($114 indirect and $18 direct costs), $355 ($271 indirect and $84 direct costs), and $653 ($494 indirect and $159 direct costs) for women with mild, moderate, and severe NVP, respectively. Costs increased with increasing severity of NVP.

CONCLUSIONS

Nausea and vomiting of pregnancy imposes an economic burden, particularly with respect to productivity losses. Limitations of the study could be potential recall bias, the unavailability of household income and follow-up interviews.

Ecological measures of socioeconomic status and hospital readmissions for asthma among Canadian adults

BACKGROUND

Lack of an association between area-based socioeconomic status (SES) and readmission for asthma was investigated in a country with a universal health care system.

METHODS

Data linkage analysis was conducted based on hospitalization data from Statistics Canada's Person-oriented Information Database and area-based SES data from the 1996 Census. Hospital records for 8333 asthma patients aged 20-64 years in all Canadian provinces except Quebec who were admitted in 1995/1996 were linked to determine the number of patients who were rehospitalized within the same fiscal year. The area-based SES of the patients was defined according to the average personal income and proportion of residents with a university degree in an enumeration area (EA). Incidence rates of readmission for asthma were calculated based on the total years at risk. Cox's proportional hazard model was used to adjust for age, sex, province, and length of stay for first admission.

RESULTS

The incidence rate of asthma rehospitalization was 31.6 per 100 person-years for men and 37.2 per 100 person-years for women. Neither average EA income or education level was significantly associated with rehospitalization for asthma. Women living in poor areas tended to have an increased incidence of asthma rehospitalization, but the difference was not significant after adjustment for covariates using the Cox regression model.

CONCLUSION

Socioeconomic status measured at the neighborhood level has no significant impact on rehospitalization for asthma among Canadian adults.

Children in need of Pharmacare: medication funding requests at the Toronto Hospital for Sick Children

OBJECTIVES

Although a national Pharmacare program ensuring access to and affordability of needed medications has repeatedly been cited as a priority to policymakers, 20% of families remain either uninsured or under-insured. The Hospital for Sick Children's Patient Amenities Fund (PAF) covers out-of-pocket medication expenses for inpatient and outpatient children. The research objectives were to 1) examine family demographics and socio-economic status (SES), the types of medications requested and government program process issues of PAF applicants in 1998 and 1999, and 2) describe trends in PAF requests from 1998 to 2000.

METHODS

Data were extracted retrospectively from fund requests, charts and social work and discharge planning reports. Descriptive statistics were used to summarize the data and to examine time trends.

RESULTS

Eighty-six applicants submitted 112 requests from 1998-1999. Most were for children with cancer, neurological disorders and transplant patients. Medication expenditures were 22,408 dollars in 1999, a 39% increase over 1998. Most requests came from two-parent nuclear families where one or both parents were employed. High deductibles, waiting time, application form complexity and request denials were cited as problems encountered with government drug plans.

DISCUSSION

The findings suggest that for provinces that do not provide universal drug insurance programs, relying on a patchwork of government plans and community agencies may not be effective in ensuring easy and timely access to necessary medications for children.

Evaluation of the impact of a pharmaceutical care program in children with asthma

The objective of this study was to evaluate the impact of a pharmaceutical care program on children with asthma. A comprehensive asthma education and monitoring program that includes basic asthma knowledge, symptoms and exacerbation evaluation, pharmacotherapy assessment including inhaler technique, and quality of life measurements was developed and applied in an outpatient paediatric clinic of the Catholic University of Chile. All patients with moderate asthma scheduled for outpatient visits with their internist over a 1-year period were referred for pharmacist intervention. Patients (aged 7-17) with moderate asthma attending the clinic were allocated to the intervention (group A) or control group (group B). Intervention patients were educated on their disease, pharmacotherapy, self-management, and inhalation techniques. The group B were children with their regular treatment for asthma but without pharmaceutical intervention. A paediatric asthma quality of life questionnaire (PAQLQ) was applied to both groups at 0, 2, and 9 weeks to assess the quality of life. Spirometry was done at the beginning and at the completion of the 9-week study. Beta-agonists used by each patient were also recorded. Eleven children (10.0+/-0.7 years) were included in the pharmaceutical care program, and ten children (9.9+/-0.6 years) in group B. For the individual domains of activities (A), emotions (E), and symptoms (S) there was a significant improvement in the children who received pharmaceutical care in comparison with those who did not receive it. The scores of group B did not change during the 9 weeks of follow-up. There were no significant changes in spirometric values in either group.

Costs of asthma in a cohort of Swiss adults: associations with exacerbation status and severity

OBJECTIVE

This article will address the effect of exacerbation status, disease severity (defined by medication required), and other variables on resource use and costs for asthma in Switzerland in 1996 to 1997.

METHODS

A retrospective chart-based study was performed. A sample of 422 adults was analyzed. Target variables were stratified by disease severity and exacerbation status. Bivariate associations were assessed. Multiple linear regression was performed on the logarithm of direct medical costs.

RESULTS

The probability of exacerbations was positively associated with disease severity. Resource use and costs were associated with both of these variables. Multiple linear regression identified age, presence of asthma-related comorbidities, degree of severity, exacerbation status, quick reliever versus controller therapy, and diagnosis or treatment by a pulmonologist as independent influences on direct costs. An interaction between severity and exacerbation status was also noted. Regression identified direct costs in the highest severity group to be 2.5 times higher than those in the lowest group, if there were no exacerbations. If exacerbations were present, costs were 5.7 times higher.

CONCLUSIONS

Because of its high prevalence, asthma has a high impact on public health. This impact depends on disease severity and, according to these findings, may also depend on the extent to which exacerbations are avoided or at least controlled.

Economic evaluation of the benefits of reducing acute cardiorespiratory morbidity associated with air pollution

BACKGROUND

Few assessments of the costs and benefits of reducing acute cardiorespiratory morbidity related to air pollution have employed a comprehensive, explicit approach to capturing the full societal value of reduced morbidity.

METHODS

We used empirical data on the duration and severity of episodes of cardiorespiratory disease as inputs to complementary models of cost of treatment, lost productivity, and willingness to pay to avoid acute cardiorespiratory morbidity outcomes linked to air pollution in epidemiological studies. A Monte Carlo estimation procedure was utilized to propagate uncertainty in key inputs and model parameters.

RESULTS

Valuation estimates ranged from 13 dollars (1997, Canadian) (95% confidence interval, 0-28 dollars) for avoidance of an acute respiratory symptom day to 5,200 dollars (4,000 dollars-6,400 dollars) for avoidance of a cardiac hospital admission. Cost of treatment accounted for the majority of the overall value of cardiac and respiratory hospital admissions as well as cardiac emergency department visits, while lost productivity generally represented a small proportion of overall value. Valuation estimates for days of restricted activity, asthma symptoms and acute respiratory symptoms were sensitive to alternative assumptions about level of activity restriction. As an example of the application of these values, we estimated that the observed decrease in particulate sulfate concentrations in Toronto between 1984 and 1999 resulted in annual benefits of 1.4 million dollars (95% confidence interval 0.91-1.8 million dollars) in relation to reduced emergency department visits and hospital admissions for cardiorespiratory disease.

CONCLUSION

Our approach to estimating the value of avoiding a range of acute morbidity effects of air pollution addresses a number of limitations of the current literature, and is applicable to future assessments of the benefits of improving air quality.

Predicting emergency department utilization in adults with asthma: a cohort study

A consecutive sample of 378 adults with asthma were assessed at a university asthma program and then interviewed 1 year later regarding their need for emergency department (E.D.) asthma treatment. The purpose of this prospective cohort study was to determine whether any of their initial features could predict their subsequent need for E.D. asthma treatment. At one year, a total of 73 of the subjects had attended emergency departments for asthma. On entry, the 73 subjects had demonstrated more self-reported lifestyle restriction from asthma and more hospital admissions E.D. visits for asthma as well as poorer asthma control or than had the 305 subjects who had not required E.D. asthma treatment since entry to the cohort. This study suggests that special attention should be paid to subjects with asthma that interferes with their lifestyle and to those who have needed hospital admission for asthma.

Measuring productivity loss days in asthma patients. The Pharmacy Medication Monitoring Program and Advisory Board

In assessments of the cost of illness, productivity losses potentially constitute a large proportion. The present study objective was to develop a method to measure restricted days and to quantify total productivity loss days (PLDs) in adult asthma patients. Patient and disease characteristics, occupation, annual wage, work absences, restricted days, level of functioning on restricted days, and travel and waiting time were collected over 6 months in 892 adult asthma outpatients residing in southern Ontario. Annual PLDs varied from 12 in employed persons to 49 in disability pensioners. Homemakers reported 22 PLDs per year. Restricted days accounted for most PLDs and functional level during restricted days varied from 55% to 81%. Annual PLDs increased with increasing disease severity. Employed persons experienced the fewest PLDs and functioned at the highest level during restricted days, but also demonstrated a milder disease compared with other groups. Most productivity loss in asthma patients resulted from numerous restricted days, a category of PLD that is often ignored in economic assessments. The presentation of PLD results disaggregated by category of time loss and wage rate may provide valuable information to employers and health policy makers and may facilitate the application of multiple approaches to the calculation of indirect costs.