Health care utilization in chronic obstructive pulmonary disease. A case-control study in a health maintenance organization

Identifying and characterizing COPD patients in US managed care. A retrospective, cross-sectional analysis of administrative claims data

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death among US adults and is projected to be the third by 2020. In anticipation of the increasing burden imposed on healthcare systems and payers by patients with COPD, a means of identifying COPD patients who incur higher healthcare utilization and costs is needed.

METHODS

This retrospective, cross-sectional analysis of US managed care administrative claims data describes a practical way to identify COPD patients. We analyze 7.79 million members for potential inclusion in the COPD cohort, who were continuously eligible during a 1-year study period. A younger commercial population (7.7 million) is compared with an older Medicare population (0.115 million). We outline a novel approach to stratifying COPD patients using "complexity" of illness, based on occurrence of claims for given comorbid conditions. Additionally, a unique algorithm was developed to identify and stratify COPD exacerbations using claims data.

RESULTS

A total of 42,565 commercial (median age 56 years; 51.4% female) and 8507 Medicare patients (median 75 years; 53.1% female) were identified as having COPD. Important differences were observed in comorbidities between the younger commercial versus the older Medicare population. Stratifying by complexity, 45.0%, 33.6%, and 21.4% of commercial patients and 36.6%, 35.8%, and 27.6% of older patients were low, moderate, and high, respectively. A higher proportion of patients with high complexity disease experienced multiple (≥2) exacerbations (61.7% commercial; 49.0% Medicare) than patients with moderate- (56.9%; 41.6%), or low-complexity disease (33.4%; 20.5%). Utilization of healthcare services also increased with an increase in complexity.

CONCLUSION

In patients with COPD identified from Medicare or commercial claims data, there is a relationship between complexity as determined by pulmonary and non-pulmonary comorbid conditions and the prevalence of exacerbations and utilization of healthcare services. Identification of COPD patients at highest risk of exacerbations using complexity stratification may facilitate improved disease management by targeting those most in need of treatment.

Geographic disparity in COPD hospitalization rates among the Texas population

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality caused by cigarette smoking and other environmental exposures. While variation in exposures may affect COPD morbidity and mortality, little is known about geographic variation, a surrogate of exposures. The objective of this manuscript is to explore the geographic variation in COPD hospitalization rates among the Texas population in 2006.

METHODS

The study population consisted of all Texas residents with COPD hospitalizations in the 2006 Texas Health Care Information Council (THCIC) data. County population estimates stratified by race, age, and gender were linked to THCIC data to calculate county level COPD hospitalization rates per 100,000 admissions. The data were merged with Urban Influence Codes by county, and metropolitan status was determined by United States Department of Agriculture (USDA) criteria. Variation in COPD hospitalization rates were analyzed using Poisson Regression.

RESULTS

Overall, non Hispanic (NH) Whites had the highest rate of hospitalization, followed by NH Blacks (rate ratio=0.42) and Hispanics (RR=0.17), the 65+ age category had the highest rates of hospitalization. In the metropolitan counties COPD hospitalization rates were lower than non-metropolitan counties, however in metropolitan counties the rates of hospitalization were significantly higher (p<0.0001) in females compared to males. The rates were significantly higher in males in public health regions 10 and 11, which are predominantly non-metropolitan counties.

CONCLUSIONS

In Texas there is substantial geographic variation in hospitalization rates associated with gender and race/ethnicity. Other factors that may contribute to the variation and require further investigation include differences in smoking and exposure to other environmental risk factors, access to primary care, medical practice patterns, and coding practices.

Determinants of elevated healthcare utilization in patients with COPD

BACKGROUND

Chronic obstructive pulmonary disease (COPD) imparts a substantial economic burden on western health systems. Our objective was to analyze the determinants of elevated healthcare utilization among patients with COPD in a single-payer health system.

METHODS

Three-hundred eighty-nine adults with COPD were matched 1:3 to controls by age, gender and area of residency. Total healthcare cost 5 years prior recruitment and presence of comorbidities were obtained from a computerized database. Health related quality of life (HRQoL) indices were obtained using validated questionnaires among a subsample of 177 patients.

RESULTS

Healthcare utilization was 3.4-fold higher among COPD patients compared with controls (p < 0.001). The "most-costly" upper 25% of COPD patients (n = 98) consumed 63% of all costs. Multivariate analysis revealed that independent determinants of being in the "most costly" group were (OR; 95% CI): age-adjusted Charlson Comorbidity Index (1.09; 1.01-1.2), history of: myocardial infarct (2.87; 1.5-5.5), congestive heart failure (3.52; 1.9-6.4), mild liver disease (3.83; 1.3-11.2) and diabetes (2.02; 1.1-3.6). Bivariate analysis revealed that cost increased as HRQoL declined and severity of airflow obstruction increased but these were not independent determinants in a multivariate analysis.

CONCLUSION

Comorbidity burden determines elevated utilization for COPD patients. Decision makers should prioritize scarce health care resources to a better care management of the "most costly" patients.

Comparative effectiveness of budesonide/formoterol and fluticasone/salmeterol for COPD management

OBJECTIVE

To compare the effectiveness of budesonide/formoterol fumarate dihydrate (BFC) and fluticasone propionate/salmeterol (FSC), two combination inhaled corticosteroid/long-acting beta-agonist (ICS/LABA) products approved for the treatment of chronic obstructive pulmonary disease (COPD) in the US with respect to cost, therapy adherence, and related healthcare utilization. The effectiveness of these two treatments has not previously been compared in a US COPD population.

METHODS

A retrospective cohort study assessed COPD-related outcomes using administrative claims data among ICS/LABA-naïve patients. Patients initiating BFC were propensity matched to FSC patients. Cost and effectiveness were measured as total healthcare expenditures, exacerbation events (hospitalizations, emergency department visits, or outpatient visits associated with oral corticosteroid or antibiotic prescription fills), and treatment medication adherence. Differences in COPD symptom control were assessed via proxy measure through claims for rescue medications and outpatient encounters.

RESULTS

Of the 6770 patients (3385 BFC and 3385 FSC), fewer BFC patients had claims for short-acting beta agonists (SABA) (34.7% vs 39.5%; p<0.001) and ipratropium (7.8% vs 9.8%, p<0.005) than FSC patients, but no substantial differences were seen in other clinical outcomes including tiotropium or nebulized SABA claims, COPD-related outpatient visits, or exacerbation events. There were no significant differences in total COPD-related medical costs in the 6-month period after initiation of combination therapy.

LIMITATIONS

This was a retrospective observational study using claims data and accuracy of COPD diagnoses could not be verified, nor was information available on severity of disease. The results and conclusions of this study are limited to the population observed and the operational definitions of the study variables.

CONCLUSIONS

For most outcomes of interest, BFC and FSC showed comparable real-world effectiveness.

Respiratory-related medical expenditure and inpatient utilisation among COPD patients receiving long-acting bronchodilator therapy

OBJECTIVE

To evaluate chronic obstructive pulmonary disease (COPD)-related expenditure and hospitalisation in COPD patients treated with tiotropium versus alternative long-acting bronchodilators (LABDs).

METHODS

Data were from the Thomson Reuters MarketScan Research Databases. COPD patients ≥ 35 years with at least one LABD claim between July 1, 2004 and June 30, 2006 were classified into five cohorts based on index LABD: monotherapy with tiotropium, salmeterol/fluticasone propionate, formoterol fumarate, or salmeterol or combination therapy. Demographic and clinical characteristics were evaluated for a 6-month pre-period and COPD-related utilisation and total costs were evaluated for a 12-month follow-up period. LABD relationship to COPD-related costs and hospitalisations were estimated by multivariate generalised linear modelling (GLM) and multivariate logistic regression, respectively.

RESULTS

Of 52,274 patients, 53% (n = 27,457) were male, 71% (n = 37,271) were ≥ 65 years, and three LABD cohorts accounted for over 90% of the sample [53% (n = 27,654) salmeterol/fluticasone propionate, 23% (n = 11,762) tiotropium, and 15% (n = 7755) combination therapy]. Patients treated with salmeterol/fluticasone propionate (p < 0.001), formoterol fumarate (p = 0.032), salmeterol (p = 0.004), or with combination therapy (p < 0.001) had higher COPD-related costs and a greater risk of inpatient admission (p < 0.01 for all) versus tiotropium.

LIMITATIONS

These data are based on administrative claims and as such do not include clinical information or information on risk factors, like smoking status, that are relevant to this population.

CONCLUSIONS

Patients treated with tiotropim had lower COPD-related expenditures and risk of hospitalisation than patients treated with other LABDs.

Lack of association of ischemic heart disease with COPD when taking into account classical cardiovascular risk factors

The aim of our study is to determine whether chronic obstructive pulmonary disease (COPD) is an independent risk factor for ischemic heart disease and whether this association is related with a greater prevalence of classical cardiovascular risk factors. Ours is a case-control cross-sectional study design. Cases were hospital patients with ischemic heart disease in stable phase, compared with control hospital patients. All patients underwent post-bronchodilator (PBD) spirometry, a standardized questionnaire, and blood analysis. COPD was defined as per GOLD PBD forced expiratory volume in the first second (FEV₁)/forced vital capacity (FVC) < 0.70. In our series of patient cases (n = 204) and controls (n = 100), there were 169 men in the case group (83%) and 84 in the control group (84%). Ages were 67 and 64 years, respectively (P < 0.05). There were no significant differences by weight, body mass index (BMI), packyears, leukocytes, or homocysteine. The abdominal perimeter was significantly greater in cases (mean 101 cm ± standard deviation [SD] 10 versus 96 cm ± 11; P < 0.000). Both groups also had significant differences by C-reactive protein (CRP), fibrinogen, and hemoglobin values. In univariate analysis, increased risks for cases to show with individual classical cardiovascular risk factors were seen, with odds ratio (OR) 1.86 and 95% confidence interval (CI) (1.04–3.33) for diabetes mellitus, dyslipidemia (OR 2.10, 95% CI: 1.29–3.42), arterial hypertension (OR 2.47, 95% CI: 1.51–4.05), and increased abdominal perimeter (OR 1.71, 95% CI: 1.06–2.78). Percent predicted PBD FEV₁ was 97.6% ± 23% in the patient group and 104% ± 19% in the control group (P = 0.01), but the prevalence of COPD was 24.1% in cases and 21% in controls. Therefore, COPD was not associated with ischemic heart disease: at the crude level (OR 1.19, 95% CI: 0.67–2.13) or after adjustment (OR 1.14, 95% CI:0.57–2.29). In conclusion, COPD was not associated with ischemic heart disease. The greater prevalence of classical cardiovascular risk factors in COPD patients could explain the higher occurrence of ischemic heart disease in these patients.

Excessive costs of COPD in ever-smokers. A longitudinal community study

AIM

We aimed to estimate the societal treatment-related costs of COPD in hospital- and population-based subjects with spirometry defined COPD, relative to a control group.

METHODS

81 COPD cases and 132 controls without COPD were randomly recruited from a general population, as were 205 COPD patients from a hospital register. All participants were ever-smokers of at least 40 years of age, followed for 12 months. Data on comorbid conditions and spirometry were collected at baseline. Standardized telephone interviews every third month gave information on use of healthcare services and exacerbations of respiratory symptoms.

RESULTS

The increased (excessive) median annual costs per case having stage II, stage III and stage IV COPD were € (95% CI) 400 (105-695), 1918 (1268-2569) and 1870 (1031-2709), respectively, compared to the population-based controls. Costs increased with €81 (95% CI 50-112) per exacerbation of respiratory symptoms and €461 (95% CI 354-567) per comorbid condition. Excessive costs for hospital COPD patients were threefold that of the population-based COPD cases.

CONCLUSION

The excessive treatment-related cost of COPD stage II+ in ever-smokers of at least 40 years was estimated to €105 million for Norway. Comorbidity was a dominant predictor of excessive cost in COPD.

Economics of COPD: literature review and experiences from field work

INTRODUCTION

The burden of diseases should be described in terms of costs. The available literature gives imprecise estimates of costs of chronic obstructive pulmonary disease (COPD) in the Nordic populations. Previous studies have methodological weaknesses related to choice of disease criteria, the use of highly selected populations and insufficient specification of the cost process. There are no robust estimates concerning the economics of COPD in Norway.

METHODS

We have conducted a 1 year follow-up cost of illness study in a general population, recruiting ever-smoking Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage 2+ COPD patients and ever-smokers without COPD. We have used diaries to recollect data, and comprehensive questionnaires to cover all costs of COPD.

RESULTS

The main challenges were the participants' unwillingness to complete diaries, the large amount of information and the logistics related to following up 476 individuals on four occasions during one year.

CONCLUSIONS

We doubt the effect of diaries. However, we recommend a detailed planning of logistics and to emphasize main cost drivers.

Physical activity, health status and risk of hospitalization in patients with severe chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a leading cause of death and 70% of the cost of COPD is due to hospitalizations. Self-reported daily physical activity and health status have been reported as predictors of a hospitalization in COPD but are not routinely assessed.

OBJECTIVES

We tested the hypothesis that self-reported daily physical activity and health status assessed by a simple question were predictors of a hospitalization in a well-characterized cohort of patients with severe emphysema.

METHODS

Investigators gathered daily physical activity and health status data assessed by a simple question in 597 patients with severe emphysema and tested the association of those patient-reported outcomes to the occurrence of a hospitalization in the following year. Multiple logistic regression analyses were used to determine predictors of hospitalization during the first 12 months after randomization.

RESULTS

The two variables tested in the hypothesis were significant predictors of a hospitalization after adjusting for all univariable significant predictors: >2 h of physical activity per week had a protective effect [odds ratio (OR) 0.60; 95% confidence interval (95% CI) 0.41-0.88] and self-reported health status as fair or poor had a deleterious effect (OR 1.57; 95% CI 1.10-2.23). In addition, two other variables became significant in the multivariate model: total lung capacity (every 10% increase) had a protective effect (OR 0.88; 95% CI 0.78-0.99) and self-reported anxiety had a deleterious effect (OR 1.75; 95% CI 1.13-2.70).

CONCLUSION

Self-reported daily physical activity and health status are independently associated with COPD hospitalizations. Our findings, assessed by simple questions, suggest the value of patient-reported outcomes in developing risk assessment tools that are easy to use.

Fixed airflow obstruction due to asthma or chronic obstructive pulmonary disease: 5-year follow-up

BACKGROUND

Both smokers and patients with asthma can experience fixed airflow obstruction, which is associated with distinctive patterns of airway pathology. The influence of fixed airflow obstruction on the prognosis of these patients is unknown.

OBJECTIVE

We sought to investigate lung function decline and exacerbations in a 5-year prospective study of subjects with fixed airflow obstruction due to asthma or chronic obstructive pulmonary disease (COPD). We also sought to explore correlations between functional, pathological, and clinical features.

METHODS

Patients with fixed airflow obstruction due to asthma (n = 16) or COPD (n = 21) and a control group of asthmatic patients with fully reversible airflow obstruction (n = 15) were followed for 5 years.

RESULTS

The rates of decline in FEV(1) were similar in patients with fixed airflow obstruction caused by asthma (-49.7 +/- 10.6 mL/y) or COPD (-51.4 +/- 9.8 mL/y) and were higher than in asthmatic patients with reversible airflow obstruction (-18.1 +/- 10.1 mL/y, P < .01). Exacerbation rates were also higher in patients with fixed airflow obstruction caused by asthma (1.41 +/- 0.26 per patient-year) or COPD (1.98 +/- 0.3 per patient-year) compared with those seen in asthmatic patients with reversible airflow obstruction (0.53 +/- 0.11 per patient-year, P < .01). Baseline exhaled nitric oxide levels and sputum eosinophil counts correlated with the FEV(1) decline in asthmatic patients with fixed airflow obstruction. By contrast, baseline sputum neutrophil counts, emphysema scores, comorbidities, and exacerbation frequency correlated directly and pulmonary diffusion capacity correlated inversely with the FEV(1) decline in patients with COPD.

CONCLUSION

In both patients with asthma and those with COPD, fixed airflow obstruction is associated with increased lung function decline and frequency of exacerbations. Nevertheless, the decline in lung function entails the specific pathological and clinical features of the underlying diseases.

The influence of heart disease on characteristics, quality of life, use of health resources, and costs of COPD in primary care settings

Background

To evaluate the influence of heart disease on clinical characteristics, quality of life, use of health resources, and costs of patients with COPD followed at primary care settings under common clinical practice conditions.

Methods

Epidemiologic, observational, and descriptive study (EPIDEPOC study). Patients ≥ 40 years of age with stable COPD attending primary care settings were included. Demographic, clinical characteristics, quality of life (SF-12), seriousness of the disease, and treatment data were collected. Results were compared between patients with or without associated heart disease.

Results

A total of 9,390 patients with COPD were examined of whom 1,770 (18.8%) had heart disease and 78% were males. When comparing both patient groups, significant differences were found in the socio-demographic characteristics, health profile, comorbidities, and severity of the airway obstruction, which was greater in patients with heart disease. Differences were also found in both components of quality of life, physical and mental, with lower scores among those patients with heart disease. Higher frequency of primary care and pneumologist visits, emergency-room visits and number of hospital admissions were observed among patients with heart diseases. The annual total cost per patient was significantly higher in patients with heart disease; 2,937 ± 2,957 vs. 1,749 ± 2,120, p < 0.05. Variables that were showed to be independently associated to COPD in subjects with hearth conditions were age, being inactive, ex-smokers, moderate physical exercise, body mass index, concomitant blood hypertension, diabetes, anxiety, the SF-12 physical and mental components and per patient per year total cost.

Conclusion

Patients with COPD plus heart disease had greater disease severity and worse quality of life, used more healthcare resources and were associated with greater costs compared to COPD patients without known hearth disease.

A new method for examining the cost savings of reducing COPD exacerbations

BACKGROUND

Some treatments for chronic obstructive pulmonary disease (COPD) can reduce exacerbations, and thus could have a favourable impact on overall healthcare costs.

OBJECTIVE

To evaluate a new method for assessing the potential cost savings of COPD controller medications based on the incidence of exacerbations and their related resource utilization in the general population.

METHODS

Patients with COPD (n = 1074) enrolled in a regional managed care system in the US were identified using administrative data and divided by their medication use into three groups (salbutamol, ipratropium and salmeterol). Exacerbations were captured using International Classification of Diseases, Ninth Edition (ICD-9) and current procedural terminology (CPT) codes, then logistic regression models were created that described the risk of exacerbations for each comparator group and exacerbation type over a 6-month period. A Monte Carlo simulation was then applied 1000 times to provide the range of potential exacerbation reductions and cost consequences in response to a range of hypothetical examples of COPD controller medications.

RESULTS

Exacerbation events for each group could be modelled such that the events predicted by the Monte Carlo estimates were very close to the actual prevalences. The estimated cost per exacerbation avoided depended on the incidence of exacerbation in the various subpopulations, the assumed relative risk reduction, the projected daily cost for new therapy, and the costs of exacerbation treatment.

CONCLUSIONS

COPD exacerbation events can be accurately modelled from the healthcare utilization data of a defined cohort with sufficient accuracy for cost-effectiveness analysis. Treatments that reduce the risk or severity of exacerbations are likely to be cost effective among those patients who have frequent exacerbations and hospitalizations.

Costs of inpatient and emergency department care for chronic obstructive pulmonary disease in an elderly Medicare population

OBJECTIVE

Treatment in the hospital setting accounts for the largest portion of healthcare costs for COPD, but there is little information about components of hospital care that contribute most to these costs. The authors determined the costs and characteristics of COPD-related hospital-based healthcare in a Medicare population.

METHODS

Using administrative data from 602 hospitals, 2008 costs of COPD-related care among Medicare beneficiaries age ≥ 65 years were calculated for emergency department (ED) visits, simple inpatient admissions and complex admissions (categorized as intubation/no intensive care, intensive care/no intubation, and intensive care/intubation) in a cross-sectional study. Rates of death at discharge and trends in costs, length of stay and readmission rates from 2005 to 2008 also were examined.

MAIN RESULTS

There were 45,421 eligible healthcare encounters in 2008. Mean costs were $679 (SD, $399) for ED visits (n = 10,322), $7,544 ($8,049) for simple inpatient admissions (n = 25,560), and $21,098 ($46,160) for complex admissions (n = 2,441). Intensive care/intubation admissions (n = 460) had the highest costs ($45,607, SD $94,794) and greatest length of stay (16.3 days, SD 13.7); intubation/no ICU admissions had the highest inpatient mortality (42.1%). In 2008, 15.4% of patients with a COPD-related ED visit had a repeat ED visit and 15.5-16.5% of those with a COPD-related admission had a readmission within 60 days. From 2005 to 2008, costs of admissions involving intubation increased 10.4-23.5%. Study limitations include the absence of objective clinical data, including spirometry and smoking history, to validate administrative data and permit identification of disease severity.

CONCLUSIONS

In this Medicare population, COPD exacerbations and related inpatient and emergency department care represented a substantial cost burden. Admissions involving intubation were associated with the highest costs, lengths of stay and inpatient mortality. This population needs to be managed and treated adequately in order to prevent these severe events.

High COPD prevalence in patients with liver disease

OBJECTIVE

Comorbidities of chronic obstructive pulmonary disease (COPD) have been recognized as an important issue in COPD management. We have reported that patients with liver diseases show a higher prevalence of COPD, but the number of patients with liver diseases was small and the details of liver diseases were not clearly investigated. In this study, we investigated the prevalence of COPD in patients with liver diseases by recruiting a large number of patients, and also investigated was the effect of hepatitis virus infection on COPD prevalence.

PATIENTS AND METHODS

Six hundred sixty-six patients were recruited from 9 primary care clinics and three hospitals. All of these patients were aged 40 years or older with chronic diseases and had not been diagnosed as having respiratory diseases. A spirometry was performed without administration of an inhaled bronchodilator. Airflow limitation was defined as FEV1/FVC<70%. Underlying diseases were diagnosed by doctors of the clinics or the hospitals.

RESULTS

Two hundred fifty-six patients had liver diseases, and 410 did not. Of 410 patients without liver diseases, 37 patients (9.0%) were diagnosed as COPD, and of 256 patients with liver diseases, 35 patients (13.8%) were COPD. When the prevalence was analyzed according to smoking, age and gender, liver diseases showed a significantly high odds ratio (2.10, 95%CI 1.23-3.57, p=0.006), but hepatitis virus infection showed a non-significant tendency toward a high odds ratio.

CONCLUSION

The patients with liver diseases had a significantly high prevalence of COPD. The presence of liver disease might become a useful predictor for the early detection of COPD.

Economic implications of comorbid conditions among Medicaid beneficiaries with COPD

OBJECTIVES

To characterize a comprehensive comorbidity profile and to explore the economic implications of comorbidity among patients with chronic obstructive pulmonary disease (COPD).

METHODS

This retrospective cohort study analyzed medical claims from the Maryland Medicaid database. We employed a 1:2 case-control design to select COPD patients (n=1388) and demographically matched controls (n=2776) aged 40 to 64 years with 24 months of continuous enrollment. Odds ratios were employed to compare comorbidity differences, including 17 conditions defined by the Charlson Comorbidity Index (CCI) and 6 additional conditions commonly observed in COPD patients. We estimated the incremental medical utilization and medical cost by specific condition.

RESULTS

Compared with the controls, Medicaid COPD patients had higher comorbidity burden and were more likely to have myocardial infarction, congestive heart failure, cerebrovascular disease, peptic ulcer, mild liver disease, hypertension, sleep apnea, tobacco use, and edema. COPD patients on average had 24% more medical claims (81.4 vs. 65.4, p<0.001) and were 33% more expensive than controls ($7603 vs. $5732, p<0.001). Ten conditions defined by the CCI as well as hypertension, tobacco use, and edema were associated with incremental medical utilization and cost in COPD patients; depression was associated with incremental medical utilization but not cost.

CONCLUSIONS

The high burden of comorbidity in COPD patients translates into additional medical utilization and cost. Effective disease management and treatment protocols are needed to reduce comorbidity burden. The development of a COPD-specific comorbidity measure may be used to identify high-risk subgroups and to predict utilization and cost.

Chronic obstructive pulmonary disease in the elderly: an update on pharmacological management

The prevalence of chronic obstructive pulmonary disease (COPD) continues to rise in association with an aging Western society. While barriers to receiving optimal healthcare exist for aging patients, pharmacotherapy of COPD in the elderly is important because the treatment benefits in this group are comparable to those seen in the younger COPD population. The frequent presence of co-morbidities and reduced clearance capacity make selection of pharmacotherapy in elderly patients with stable COPD challenging. The adverse effects of standard therapy for COPD may also be more pronounced in elderly patients. A careful risk-versus-benefit assessment should always be carried out when prescribing long-term inhaled bronchodilator and corticosteroid therapy to an elderly COPD patient, and when prescribing beta(2)-adrenoceptor agonists and methylxanthines, in particular, to those with cardiovascular co-morbidities. The present review focuses on the special considerations regarding initiation and maintenance of pharmacotherapy in elderly patients with stable COPD.

Assessment of the Economic Burden of COPD in the U.S.: A Review and Synthesis of the Literature

The costs of chronic obstructive pulmonary disease (COPD) pose a major economic burden to the United States. Studies evaluating COPD costs have generated widely variable estimates; we summarized and critically compared recent estimates of the annual national and per-patient costs of COPD in the U.S. Thirteen articles reporting comprehensive estimates of the direct costs of COPD (costs related to the provision of medical goods and services) were identified from searches of relevant primary literature published since 1995. Few papers reported indirect costs of COPD (lost work and productivity). The National Heart, Lung, and Blood Institute (NHLBI) provides the single current estimate of the total (direct plus indirect) annual cost of COPD to the U.S., $38.8 billion in 2005 dollars. More than half of this cost ($21.8 billion) was direct, aligning with the $20-26 billion range reported by two other recent analyses of large national datasets. For per-patient direct costs (in $US 2005), studies using recent data yield attributable cost estimates (costs deemed to be related to COPD) in the range of $2,700-$5,900 annually, and excess cost estimates (total costs incurred by COPD patients minus total costs incurred by non-COPD patients) in the range of $6,100-$6,600 annually. Studies of both national and per-patient costs that use data approximately 8-10 years old or older have produced estimates that tend to deviate from these ranges. Cost-of-illness studies using recent data underscore the substantial current cost burden of COPD in the U.S.

Factors affecting chronic obstructive pulmonary disease (COPD)-related costs: a multivariate analysis of a Swedish COPD cohort

Chronic obstructive pulmonary disease (COPD) is an increasing public health problem, generating considerable costs. The objective of this study was to identify factors affecting COPD-related costs. A cohort of 179 subjects with COPD was interviewed over the telephone on four occasions about their annual use of COPD-related resources. The data set and explanatory variables were analysed by means of multivariate regression techniques for six different types of cost: societal (or total), direct (health care) and indirect (productivity), and three subcomponents of direct costs-hospitalisation, outpatient and medication. Poor lung function, dyspnoea and asthma were independently associated with higher costs. Poor lung function (severity of COPD) significantly increased all six examined cost types. Dyspnoea (breathing problems) also increased costs, though to a varying extent. The presence of reported asthma increased total, direct, outpatient and medication costs. Poor lung function and, to a lesser extent, extent of dyspnoea and concomitant asthma, were all strongly associated with higher COPD-related costs. Strong efforts should be made to prevent the progression of COPD and its symptoms.

Health care costs among individuals with chronic obstructive pulmonary disease within several large, multi-state employers

OBJECTIVE

To estimate chronic obstructive pulmonary disease (COPD)-attributable medical resource utilization and health care costs among employed individuals and their covered dependents with COPD.

METHOD

Retrospective health care claims analysis. Employees and dependents 40 to 63 years old with a diagnosis of COPD between January 1, 2001 and December 31, 2002 were matched to two separate control cohorts. Medical resource utilization and health care costs were compared between cohorts.

RESULTS

A total of 6445 individuals with COPD were matched to each control cohort. Mean age was 55.1 years, and cohorts were approximately 50% men. COPD subjects had significantly higher utilization and adjusted pharmacy, medical, and total health care costs than both control cohorts (P < 0.001).

CONCLUSIONS

COPD subjects had significantly higher utilization and costs than individuals without COPD. Thus, the economic burden of COPD is present in younger, working individuals, as well as in the older, retired population.

Healthcare costs associated with initial maintenance therapy with fluticasone propionate 250 μg/salmeterol 50 μg combination versus anticholinergic bronchodilators in elderly US Medicare-eligible beneficiaries with COPD

OBJECTIVE

To compare, in elderly Medicare beneficiaries, chronic obstructive pulmonary disease (COPD)-related healthcare costs for patients initiating treatment with fluticasone propionate/salmeterol 250 μg/50 μg (FSC) with those for patients initiating treatment with ipratropium bromide/albuterol (IPA), ipratropium bromide (IPR), and tiotropium bromide (TIO).

METHODS

In this retrospective, observational, cohort study, COPD-related medical costs (inpatient/emergency department, outpatient) and pharmacy costs were assessed in Medicare beneficiaries ≥ 65 years old who were enrolled in a commercial Medicare health maintenance organization plan and had a diagnosis of COPD (ICD-9-CM codes 491.xx, 492.xx, or 496.xx) within 12 months before initial treatment with FSC, IPA, IPR, or TIO.

RESULTS

In these ≥ 65-year-old patients (N=14,689), initial maintenance treatment with FSC was associated with total COPD-related cost savings (medical + pharmacy) of $295 versus IPA, $1,235 versus IPR, and $110 versus TIO (p<0.05, each comparison) over a 1-year follow-up period.

CONCLUSIONS

Initiation of maintenance therapy with FSC was associated with significant reduction in total costs (medical + pharmacy) relative to costs associated with the short-acting anticholinergic bronchodilators IPR and IPA and the long-acting anticholinergic bronchodilator TIO in an elderly Medicare-eligible population. These data considered in the context of the substantial efficacy and effectiveness data suggest that early introduction of maintenance treatment with FSC has both clinical and economic benefits. Limitations inherent in handling of administrative data include lack of objective clinical measures such as spirometry and smoking status. Furthermore, accuracy of diagnosis codes cannot be verified.

Comorbidities in chronic obstructive pulmonary disease

Comorbidities such as cardiac disease, diabetes mellitus, hypertension, osteoporosis, and psychological disorders are commonly reported in patients with chronic obstructive pulmonary disease (COPD) but with great variability in reported prevalence. Tobacco smoking is a risk factor for many of these comorbidities as well as for COPD, making it difficult to draw conclusions about the relationship between COPD and these comorbidities. However, recent large epidemiologic studies have confirmed the independent detrimental effects of these comorbidities on patients with COPD. On the other hand, many of these comorbidities are now considered to be part of the commonly prevalent nonpulmonary sequelae of COPD that are relevant not only to the understanding of the real burden of COPD but also to the development of effective management strategies.

[Cardiovascular risk factors in chronic obstructive pulmonary disease: results of the ARCE study]

OBJECTIVE

Cardiovascular disease is a common cause of death in patients with chronic obstructive pulmonary disease (COPD). It is not clear whether the high cardiovascular comorbidity is due to an increase in traditional risk factors or whether, in contrast, COPD can be considered an independent risk factor. The aim of this study was to analyze the prevalence of risk factors and cardiovascular comorbidity in a community-based population treated for COPD.

PATIENTS AND METHODS

This was a concurrent multicenter, cross-sectional study that included 572 patients with confirmed diagnosis of COPD. Information on cardiovascular risk factors and comorbidity was collected by extracting data from the medical records of the participating center.

RESULTS

The mean (SD) forced expiratory volume in 1 second (FEV1) was 53.7% (16.85%) of predicted and the ratio of FEV1 to forced vital capacity was 57.9% (10.9%). Hypertension was reported in 53%, obesity in 27%, dyslipidemia in 26%, and diabetes in 23% of the patients. The prevalence of risk factors was not related to disease severity, but there was a trend towards an association with age. In the study group, 16.4% had ischemic heart disease, 7% cerebrovascular disease, and 17% peripheral vascular disease. Cardiovascular disease was not associated with COPD severity, but such an association was reported for age and traditional risk factors.

CONCLUSIONS

Cardiovascular risk factors are highly prevalent in patients with COPD. The prevalence of cardiovascular and cerebrovascular disease exceeds that reported in the general population. No relationship was found between the severity of airflow obstruction and the presence of cardiovascular comorbidity.

The direct medical costs of undiagnosed chronic obstructive pulmonary disease

OBJECTIVE

To estimate the costs of undiagnosed chronic obstructive pulmonary disease (COPD) by describing inpatient, outpatient, and pharmacy utilization in the years before and after the diagnosis.

METHODS

A total of 6,864 patients who were enrolled in the Lovelace Health Plan for at least 12 months during the study period (January 1, 1999 through December 31, 2004) were identified. The first date that utilization was attributed to COPD was considered the first date of diagnosis. Each COPD case was matched to up to three age- and sex-matched controls. All utilization and direct medical costs during the study period were compiled monthly and compared based on the time before and after the initial diagnosis.

RESULTS

Total costs were higher by an average of $1,182 per patient in the 2 years before the initial COPD diagnosis, and $2,489 in the 12 months just before the initial diagnosis, compared to matched controls. Most of the higher cost for undiagnosed COPD was attributable to hospitalizations. Inpatient costs did not increase after the diagnosis was made, but approximately one-third of admissions after the diagnosis were attributed to respiratory disease. Outpatient and pharmacy costs did not differ substantially between cases and matched controls until just a few months before the initial diagnosis, but remained 50% to 100% higher than for controls in the 2 years after diagnosis.

CONCLUSIONS

Undiagnosed COPD has a substantial impact on health-care costs and utilization in this integrated managed care system, particularly for hospitalizations.

Chronic obstructive pulmonary disease in the older patient

Chronic obstructive pulmonary disease (COPD) is one of the most common chronic diseases in the world. It is a major cause of morbidity, mortality, and health care use, particularly in older adults. In the following sections, the authors review the diagnosis and management of COPD with a focus on special issues in older adults.

Pulmonary rehabilitation in chronic obstructive pulmonary disease

Pulmonary rehabilitation, a multidisciplinary and structured intervention for patients with chronic pulmonary diseases, has been shown to improve exercise tolerance, reduce dyspnea and improve health-related quality of life. Pulmonary rehabilitation appears to be cost-effective, since it reduces health care utilization. Exercise training represents the cornerstone of every pulmonary rehabilitation program. To obtain clinically relevant effects, training should closely supervised, of high intensity, lasting 30-45 min for at least 3 days/week. Patients should undertake a minimum of 20 sessions, but longer programs result in larger and more long-lasting effects. Education and self-management programs have been shown to result in a substantial reduction in hospital admissions. Nutritional intervention should be considered for patients who are underweight or those with body composition abnormalities. Patients reporting fear and anxiety may benefit from psychosocial support, and the integration of occupational therapy in a pulmonary rehabilitation program can improve independence in activity. Multidisciplinary pulmonary rehabilitation is preferably implemented in an outpatient hospital- or community-based setting. Inpatient programs are suited for patients with limited transportation capabilities or severe deconditioning. The most convincing effects of home-based rehabilitation are in maintaining the improvements obtained in an outpatient setting.

[Recording the daily physical activity of COPD patients with an accelerometer: An analysis of agreement and repeatability]

OBJECTIVE

The purpose of this study was to assess the agreement between different measurements of mean daily physical activity taken over a week in chronic obstructive pulmonary disease (COPD) patients with an accelerometer and to analyze the medium-term repeatability of these measurements.

PATIENTS AND METHODS

The study enrolled 12 healthy control subjects and 23 patients with stable COPD (mean [SD] forced expiratory volume in 1 second [FEV1] of 45% [13%] of predicted and a ratio of FEV1 to forced vital capacity of 53% [13%]). Accelerometer output, measured in vector magnitude units, was recorded in a physical activity log for a 1-week period. The results were then analyzed to compare output for a conventional recording period (Friday to Sunday) to that for 2 other periods (Monday to Wednesday and Tuesday to Thursday). The measurements were repeated 3 to 5 weeks later.

RESULTS

Activity counts were lower in the COPD patients than in the control subjects (184 [99] vs 314 [75]; P < .001). In the COPD patients, the results for the Friday to Sunday period correlated well with the results for both the Monday to Wednesday period (95% confidence interval, -29.21 to 28.81) and the Tuesday to Thursday period (95% confidence interval, -32.13 to 28.43). There were no significant differences in terms of medium-term repeatability of accelerometer readings between the COPD group and the control group (repeatability coefficient of 11.2% [4.6%] and 8.5% [4.7%], respectively).

CONCLUSIONS

Both agreement between the different measurements of physical activity taken during a 1-week period and medium-term repeatability for COPD patients and control subjects were very good.

Direct costs of COPD in the U.S.: an analysis of Medical Expenditure Panel Survey (MEPS) data

Chronic obstructive pulmonary disease (COPD) is a costly cause of morbidity and mortality in the U.S. The objective of this study was to use contemporary national data-specifically, those from the 2000 Medical Expenditure Panel Survey (MEPS)-to estimate direct costs of COPD in the U.S. from an all-payer perspective. Due to constraints of MEPS data, indirect costs were excluded from our analyses, as were costs of long-term oxygen therapy and costs from nursing homes and long-term care facilities. Two methods of cost estimation were employed. First, we estimated resources used and expenditures incurred by individuals with COPD that were directly attributable to the disease (attributable cost approach). Second, we compared overall medical expenditures of patients with COPD to those of the non-COPD population; the resulting difference represented excess costs of COPD. Approximately 1.7% (n = 144) of the nearly 8,300 persons in the analysis data set aged > or = 45 years used medical resources and incurred expenditures related to treatment of COPD. Mean attributable costs per patient were estimated at dollar 2,507, with more than one-half of these costs (dollar 1,365) associated with hospitalization. Mean excess costs of COPD, after adjustment for sociodemographic factors and smoking status, were substantially higher, at dollar 4,932 per patient. Results of our study indicate that COPD-associated healthcare utilization and expenditures are considerable, and that annual per-patient costs of COPD are comparable to those of other chronic diseases of the middle-aged and elderly.

Role of nontypeable Haemophilus influenzae in exacerbations and progression of chronic obstructive pulmonary disease

PURPOSE OF REVIEW

Nontypeable Haemophilus influenzae is the most common bacterial pathogen associated with airway infection in chronic obstructive pulmonary disease, both in stable disease and during exacerbations. Past attempts to elucidate its role as a pathogen in this disease yielded confusing and contradictory results, leading to its designation as an 'innocent bystander' with little if any pathogenic role in exacerbations and stable disease. Application of modern understanding of bacterial pathogenesis and of innovative research methodologies, however, has considerably clarified its role.

RECENT FINDINGS

Acquisition of antigenically diverse strains of nontypeable H. influenzae which engender a neutrophilic inflammatory response and strain-specific immunity appears to be the mechanism underlying recurrent exacerbations of chronic obstructive pulmonary disease. In the stable phase of the disease, this pathogen appears to be an inflammatory stimulus in the lower airways with the potential to contribute to progressive airway obstruction that is characteristic of the condition. Several mechanisms may allow the infection to persist in the lower airways of patients with chronic obstructive pulmonary disease, including tissue invasion, antigenic alteration and biofilm formation.

SUMMARY

Though much has been learnt about nontypeable H. influenzae in chronic obstructive pulmonary disease, new therapeutic and preventive approaches require an even greater understanding of this host-pathogen interaction.

Tiotropium in COPD patients not previously receiving maintenance respiratory medications

INTRODUCTION

Use of maintenance bronchodilator therapy is currently recommended in symptomatic patients with Chronic obstructive pulmonary disease (COPD) and in those with Stage II or greater COPD as defined by the Global Initiative for Chronic Obstructive Lung Disease (GOLD). Because no prospective data describe when rescue therapy alone is insufficient or the optimal time to start maintenance therapy, it is unclear whether maintenance therapy has benefits in milder disease. To explore potential benefits we asked: Does once-daily tiotropium improve lung function, health status, and/or symptoms in "undertreated" COPD patients (i.e., those who are not receiving maintenance bronchodilator therapy) or patients considered by their health care providers as having milder disease?

METHODS

A post-hoc analysis of data from COPD patients participating in two, 1-year, placebo-controlled trials with tiotropium was performed. Patients were defined as "undertreated" if they received no respiratory medication or only as-needed short-acting beta-agonists prior to enrollment. Measures included serial spirometry, Transition Dyspnea Index (TDI), and St. George's Respiratory Questionnaire (SGRQ).

RESULTS

Of 921 patients enrolled, 218 (23.7%) were "undertreated": 130 received tiotropium; 88 received placebo. Demographics for the two treatment groups were comparable. Tiotropium-treated patients had significantly improved forced expiratory volume in 1s (FEV1) and forced vital capacity (FVC) compared with patients using placebo on all study days. Additionally, TDI and SGRQ scores significantly improved with tiotropium compared with placebo.

CONCLUSIONS

Once-daily tiotropium provides significant improvement in lung function, health status, and dyspnea when used as maintenance therapy in undertreated COPD patients who were not previously receiving maintenance bronchodilator therapy.

Assessing the costs of chronic obstructive pulmonary disease: The state medicaid perspective

BACKGROUND

State Medicaid programs provide insurance coverage to over 40 million Americans. However, estimates of the annual cost of chronic obstructive pulmonary disease (COPD) from the Medicaid perspective are lacking.

METHODS

This retrospective cohort study used Medicaid administrative claims data from California and Florida to estimate COPD expenditures using two alternative methods: (1) excess costs (comparing a COPD cohort to a matched comparison cohort); and (2) attributable costs (COPD-related expenditures within a COPD cohort, inclusive of respiratory medications). The COPD cohort in each state included Medicaid recipients not dually eligible for Medicare who were 40+ years of age with at least one medical claim for COPD during 2001. The comparison cohort consisted of patients with medical claims during 2001 for conditions other than chronic respiratory disease, matched by age, sex, and race to the COPD cohort.

RESULTS

A total of 6,738 Medicaid recipients in California and 18,017 in Florida were included in the COPD cohort, with mean ages of 56 and 60 years, respectively. Comorbidities, especially congestive heart failure and vascular disease, were more common in the COPD cohort than among matched controls. The mean excess cost of COPD per-patient was estimated to be approximately 6,500 US dollars in California Medicaid and 5,200 US dollars in Florida Medicaid. Mean attributable costs of COPD were similar in the two Medicaid programs (approximately 2,200 US dollars and 2,300 US dollars per patient, respectively).

CONCLUSIONS

COPD places a substantial financial burden on State Medicaid programs. These findings may be of interest to clinicians and policy-makers involved in preventing or managing this chronic disease.

Economic evaluation of treating chronic obstructive pulmonary disease with inhaled corticosteroids and long-acting beta2-agonists in a health maintenance organization

OBJECTIVES

In light of recent results from observational studies showing prolonged survival in subjects taking long-acting beta2-agonists (LABA) and/or inhaled corticosteroids (ICS) for chronic obstructive pulmonary disease (COPD), we investigated their cost-effectiveness (CE).

METHODS

Costs and survival data were collected for a sample of members enrolled in a large Health Maintenance Organization in the United States. An observational study design was used to evaluate cumulative costs and health benefits of LABA, ICS, ICS+LABA, or comparison drugs. Survival was estimated using a parametric regression model. Costs were adjusted for censoring and prognostic factors. CE was evaluated over a time horizon of 36 months and the remaining lifetime of subjects.

RESULTS

Over 36 months, life expectancy and costs were: 2.4 years (95% confidence interval (CI): 2.3; 2.5) and $28,030 (CI: $23,400; $33,570) for not receiving ICS or LABA; 2.6 years (CI: 2.6; 2.7) and $35,170 (CI: $29,970; $40,620) for ICS alone; 2.6 years (CI: 2.5; 2.7) and $27,380 (CI: $21,780; $32,510) for LABA alone; and, 2.7 years (CI: 2.6; 2.8) and $33,780 (CI: $28,700; $39,440) for subjects treated with ICS+LABA. The lifetime analysis showed similar trends.

CONCLUSIONS

There is an acute need to find effective, life-extending treatments for persons with COPD. ICS, LABA or their combination represent promising treatment options and are currently being tested in randomized trials. If the impact on survival seen in these trials compares to that seen in observational studies, LABA and the combination treatment are likely to be cost-effective in the United States.

Cost-effectiveness of smoking cessation and the implications for COPD

The cost burden of COPD is substantial for patients and families, payers, and society as a whole. Smoking has been known for decades to be the leading cause of the disease. Numerous studies have been completed to address the cost-effectiveness of programs created to aid smokers in their efforts to quit. Because several assumptions must be made in order to conduct such a study, and because differences in study design are numerous, comparison of data is difficult. However, studies have consistently shown that regardless of the perspective from which the study was completed, or the methods used to help smokers abstain, the interventions are cost-effective. Although no study has been conducted specifically to assess the cost-effectiveness of smoking cessation interventions as they relate directly to patients with COPD, based on current data it can be concluded that smoking cessation programs are cost-effective for this population.

Improving the management of chronic obstructive pulmonary disease

As the fourth leading cause of death in the United States, chronic obstructive pulmonary disease (COPD) represents a major burden to the healthcare system and society at large. Underdiagnosis and undertreatment lead to an increased economic burden, with exacerbations being a key driver of costs. COPD symptoms compromise quality of life (QOL), which affects both patients and caregivers. Appropriate management decreases healthcare utiization and improves QOL. This article provides an overview of COPD and promotes understanding of opportunities to optimize patient health and outcomes for those with the disease. Specific interventions that have been demonstrated to improve clinical and economic outcomes for COPD include improved implementation of guidelines, optimized pharmacologic treatment, and risk-factor reduction.

Chronic Obstructive Pulmonary Disease in Patients Under Age 65: Utilization and Costs From a Managed Care Sample

OBJECTIVES

Chronic obstructive pulmonary disease (COPD) affects all adult age groups, not just elderly males. We assessed the health care utilization and cost impact of COPD in different age groups.

METHODS

We compared burden of illness, utilization, and charges for younger versus older COPD patients and versus age- and gender-matched controls.

RESULTS

A total of 16.9% of patients with COPD were under age 65. Patients with COPD (n=19,338) had higher comorbidity than age-matched controls (n=94,384) across all age groups. Younger patients with COPD had lower comorbidity scores and fewer hospitalizations but more COPD-related emergency services than older patients with COPD. Average COPD-related charges were higher for younger patients. Facility-based care was the cost driver across all age groups.

CONCLUSIONS

COPD is a burden to younger individuals in the workforce, who are likely to be enrolled in a commercial health plan.

A comparison of the risk of hospitalizations due to chronicobstructive pulmonary disease in medicaid patients with various medication regimens, including ipratropium, inhaled corticosteroids, salmeterol, or their combination

OBJECTIVE

The aim of this study was to compare the risk of hospitalizations related to chronic obstructive pulmonary disease (COPD) among Medicaid patients prescribed various medication regimens.

METHODS

This was an observational, retrospective study set in the Texas Medicaid program. Eligible patients were aged 40 to 65 years, had a primary or secondary diagnosis of COPD, and had >/=1 prescription for ipratropium (IPR), inhaled corticosteroids (ICS), or salmeterol (SAL) between January 1, 1998, and August 31, 2000. Five index therapy groups were included in the risk analysis: IPR alone, ICS alone, SAL alone, ICS + IPR, and ICS + SAL.

RESULTS

A total of 4447 patients were included in the study (IPR alone, n = 2435; ICS alone, n = 1088; SAL alone, n = 299; ICS + IPR, n = 410; and ICS + SAL, n = 215). After adjusting for baseline characteristics, ICS + SAL was associated with a 35% lower risk of COPD-related hospitalization (hazard ratio [HR], 0.653 [95% CI, 0.428-0.997]) versus IPR alone. ICS alone was associated with a 16% lower risk (HR, 0.844 [95% CI, 0.693-1.028]) and SAL alone was associated with a 24% lower risk (HR, 0.756 [95% CI, 0.539-1.060]) versus IPR alone, but neither of these was statistically significant. There was no decrease in risk with ICS + IPR versus IPR alone (HR, 1.111 [95% CI, 0.870-1.420]). Variables that indicated increased risk were as follows: increasing age (HR, 1.015 [95% CI, 1.003-1.027]); number of preindex emergency department visits (HR, 1.189 [95% CI, 1.080-1.309]); number of preindex hospitalization visits (HR, 1.342 [95% CI, 1.220-1.477] ); number of nonrespiratory comorbid diagnoses (HR, 1.046 [95% CI, 1.012-1.081]); and having a diagnosis of influenza/pneumonia (HR, 1.276 [95% CI, 1.062-1.533]) or other respiratory diseases (HR, 1.356 [95% CI, 1.134-1.622]). Comorbid asthma was not associated with increased risk.

CONCLUSIONS

ICS + SAL was associated with a significantly lower risk of COPD-related hospitalization compared with IPR alone during the initial 12 months of therapy in a Medicaid population. Additional studies are needed to confirm these findings across different populations.

Predicting the costs of managing patients with chronic obstructive pulmonary disease

The economic consequences of chronic obstructive pulmonary disease (COPD) are considerable, although the factors that best predict costs are largely unknown. This study used a population-based cohort to identify the clinical factors during an index year that were most predictive of increased direct medical costs in the subsequent year, and to develop a predictive model that described the cost variations in COPD. The medical records of 2116 patients enrolled in one regional health system who had COPD and health-care resource utilisation data for 1998 and 1999, were abstracted for information about symptoms, smoking history, chronic illnesses, and pulmonary function data. All inpatient, outpatient and pharmacy utilisation data for each subject for 1999 were extracted from the database. Total costs for each individual were transformed to a log scale. Potential causes of cost variability (predictor variables) were defined and classified into sets (or domains). Multiple linear regression models were fitted for each domain. The study demonstrated that severity of airflow obstruction, as assessed by FEV(1)% predicted, is a significant but weak predictor of future health-care resource utilisation-prior hospitalisation and home oxygen use, the presence of comorbid conditions and symptoms of dyspnoea are better predictors of costs. Those interested in the economic benefits of new COPD treatments and disease management programs need to carefully account for these factors.