SUBJECT REVIEW

The Economic Impact of Acute Exacerbations of Chronic Bronchitis in the United States and Canada: A Literature Review MICHAEL T. HALPERN, MD, PhD; MITCHELL K. HIGASHI, MBA, PhD; ALAN W. BAKST, PharmD; and JORDANA K. SCHMIER, MA

ABSTRACT BACKGROUND: Acute exacerbations of chronic bronchitis (AECB) are recurrent and potentially severe medical events for the 13 million people in the United States who have chronic bronchitis. Medical resource use associated with AECB can have a substantial economic impact on the patients, health care system, and society overall. OBJECTIVE: To evaluate literature on the economic impact of AECB in terms of cost of illness, cost of treatments, and cost-effectiveness. METHODS: A MEDLINE literature search was conducted for studies of chronic bronchitis and costs. Reference lists of identified articles were also retrieved for review. RESULTS: Eight published studies were identified: 2 cost-of-illness studies, 1 comparative cost study, and 5 cost-effectiveness studies. Important drivers of costs associated with AECB include hospitalization and choice of antibiotics. In mild to moderate AECB, patient adherence with therapy is essential to consider when selecting treatment. The antibiotic with the lowest acquisition cost has not been shown to be the most cost effective, as adherence and clinical outcomes, particularly rehospitalization rates, differ. CONCLUSION: Further research in these areas is needed to guide clinical decision making and the conduct of disease management programs. KEYWORDS: Chronic bronchitis, Acute exacerbations, Chronic obstructive pulmonary disease, Cost-effectiveness, Cost of illness J Managed Care Pharm. 2003;9(4):353-59

Authors MICHAEL T. HALPERN, MD, PhD, is Principal Scientist and JORDANA K. SCHMIER, MA, is Managing Scientist, Exponent, Inc., Alexandria, Virginia; MITCHELL K. HIGASHI, MBA, PhD, is Manager and ALAN W. BAKST, PharmD, is Director, Global Health Outcomes, GlaxoSmithKline, Collegeville, Pennsylvania, and Philadelphia, Pennsylvania. CORRESPONDING AUTHOR: Michael T. Halpern, MD, PhD, Exponent, Inc., 1800 Diagonal Rd., Suite 355, Alexandria, VA 22314. Tel: (571) 431-7214; Fax: (571) 431-7269; E-mail: [email protected] Copyright© 2003, Academy of Managed Care Pharmacy. All rights reserved.

A

cute exacerbations of chronic bronchitis (AECB), as the name suggests, is acute inflammation of the bronchial airways in the presence of underlying chronic bronchitis.1 AECB is generally accompanied by bacterial infections for which standard treatment is antibiotics.2 Approximately 13 million persons in the United States (almost 5% of the adult population) have chronic bronchitis and experience acute exacerbations.3,4 As such, in addition to its clinical effects, AECB is likely to have a substantial economic impact. A variety of studies have been performed to assess the costs associated with AECB and its treatment. These studies can be grouped into 3 main categories: cost-of-illness studies, which evaluate the baseline resource utilization and costs associated with AECB; comparative cost studies, which assess the difference in costs resulting from different AECB treatments; and cost-effectiveness studies, which determine the incremental change in cost per incremental improvement in patient outcomes for different AECB treatments. Each of these types of studies provides unique information on the impact of AECB. Cost-of-illness studies, also known as burden-of-illness studies, provide an assessment of all costs associated with a condition and may include societal as well as direct and indirect medical costs. Comparative cost studies are important in the evaluation of the relative costs of treatments and may be important to treatment selection. Cost-effectiveness studies, by providing a common metric such as cost per quality-adjusted lifeyear (QALY) or symptom-free day, allow for comparisons across conditions and are most appropriate for societal or health plan allocation decision making. ■■ Methods To better understand the economic impact of AECB, we reviewed the economic literature for this condition. A MEDLINE literature search was conducted to identify articles with the MeSH headings “Pulmonary Disease, Chronic Obstructive,” “Pulmonary Emphysema,” or “Bronchitis, Chronic” and headings involving the term “Cost.” There was no time or language limitation to the search, and we did not limit the search to articles with abstracts available online. Only articles providing information on medical care costs for AECB in the United States or Canada were selected. Reference lists of identified articles were reviewed for additional relevant information. ■■ Literature Search Results A total of 8 published studies on the medical care costs of AECB in the United States and Canada were identified. Two of these are cost-of-illness studies, in that they provide information only on

www.amcp.org Vol. 9, No. 4 July/August 2003

JMCP

Journal of Managed Care Pharmacy 353

The Economic Impact of Acute Exacerbations of Chronic Bronchitis in the United States and Canada: A Literature Review

the medical care costs (either inpatient only or inpatient plus outpatient) for the broad population of AECB patients. One of the identified studies is a comparative cost study, presenting differences in medical care costs for AECB patients treated with differing antibiotic therapies. Finally, 5 of the studies are cost-effectiveness studies, in that they compared both the costs and clinical outcomes for patients treated with a number of specified antibiotics. (See Table 1 for a summary of reviewed studies.)

TABLE 1

Cost-of-Illness Studies We identified 2 studies that assessed total costs associated with AECB in the United States and Canada. Both studies included data on inpatient treatment; one also included estimates of costs associated with outpatient care for AECB. Niederman et al. conducted a retrospective analysis using claims and survey data to assess resource utilization and health care system costs for patients treated for AECB.5 Medicare

Summary of Reviewed Studies*

Reference

Country

Study Design

Methods

United States

Retrospective n=60 patients with 373 AECB Data collected 1/1990-1/1994 ($U.S.1994)

Patient data obtained from medical records between January 1990 and January 1994. Patients were older than 36 years with mild-to-moderate acute infections and diagnosed chronic bronchitis documented in records. Three antibiotic groups were selected for comparison and were categorized as first-, second-, and thirdline agents.

Grossman et al.8

Canada

Randomized, multicenter, parallel-group, open-label study; n=240 (120 ciprofloxacin, 120 usual care) Data collected 11/199311/1995 ($Canadian1999)

Outpatient adult men and women aged 18 years or older with chronic bronchitis and a recent history of frequent exacerbations (3 or more within the past year) were randomized to receive either oral ciprofloxacin (500 mg bid) or usual care. Patients were seen at months 3, 6, 9, and 12 for regular visits. Patients completed 3 self-administered questionnaires at regular and follow-up visits.

Halpern et al.9

United States and Canada

Retrospective analysis of data from a randomized, prospective study n=438 (215 gemifloxacin, 224 clarithromycin) Data collected 11/1998-11/1999 ($U.S.1999)

Analysis of clinical trial data from 386 patients treated at 46 centers in the United States and 52 patients at 10 centers in Canada. Treatment effectiveness measured as the proportion of patients without recurrence requiring antibiotic treatment following resolution of the initial AECB.

Keenan et al.11

Canada

Retrospective analysis of data from published meta-analyses Reports published 1993-1998 ($Canadian1996)

Analysis of data from published meta-analyses. Decision-analysis model developed. Primary outcomes included reductions of in-hospital mortality and endotracheal intubations among patients treated with noninvasive positive pressure ventilation plus usual care versus usual care alone.

Quenzer et al.12

United States

Retrospective analysis of data collected from 12 randomized, double-blind controlled trials conducted 1987-1992 ($U.S.1995)

Analysis of 12 trials of clarithromycin, 6 of which included patients with AECB. (Others included pneumonia, AECB and pneumonia, or sinusitis.) The analysis estimated additional cost per complication-free cure, meaning a full course of therapy, satisfactory response, and no adverse events.

Smith and Pesce10

United States

Retrospective analysis of data from published reports (published 1972-1989) ($Canadian1992)

Clinical and utility data were derived from published accounts. Cost data were from Medicare reimbursement rates. The model compared cost/QALY for treatment of AECB with PAC versus no PAC, given assumptions about life expectancy following hospitalization.

Niederman et al.5

United States

Retrospective n=280,830 COPD patients (207,540 Medicare recipients, 73,299 non-Medicare recipients) ($U.S.1995)

Analysis of claims data for patients treated for AECB. Medicare was the primary data source for patients >65 years; data from the National Healthcare and Cost Utilization Project, the National Ambulatory Medical Care Survey, and the National Hospital Ambulatory Medical Care Survey were used for patients aged 100 U.S. academic hospitals) and the University of Michigan Health System for hospitalization for AECB (ICD-9 491.21) and for acute and chronic bronchitis (ICD-9 490, 491).

Comparative Cost Study Destache et al.7

Cost-effectiveness Studies

Cost-of-Illness Studies

Continued on next page

354 Journal of Managed Care Pharmacy

JMCP

July/August 2003

Vol. 9, No. 4

www.amcp.org

The Economic Impact of Acute Exacerbations of Chronic Bronchitis in the United States and Canada: A Literature Review

TABLE 1

Summary of Reviewed Studies*

(continued from previous page)

Reference

Rates of Resource Utilization

Destache et al.

First-line Agents 8.9 + 3.3

7

Days of therapy Grossman et al.8

Second-line Agents 8.3 + 2.3

Not presented Hospitalizations 2.3% 6.3%

Halpern et al.

9

Gemifloxacin Clarithromycin

RTI Hospital Days 0.20 0.37

RTI Physician Visits 0.79 0.78

Niederman et al.5

Saint et al.6

Number of Discharges 207,540 73,299 280,839

Mean Lengths of Stay (Days) 6.3 5.8 6.2

Physicians’ Office 89% 71.3%

Emergency Dept. 8.9% 25.1%

Outpatient Dept. 2.1% 3.6%

Not presented AECB University of Michigan University HealthSystem Consortium All acute and chronic bronchitis University of Michigan University HealthSystem Consortium

No. of Patients 101 12,379

Average Length of Stay (Days) 3.98 5.22

154 13,904

3.86 5.07

Reference Destache et al.7

Days of RTI Antibiotics 5.67 6.14

Inpatient and Physician Services Location

>65 years 65 years of age Patients 65 years. For patients