Costs of Treating Lower Respiratory Tract Infections

Objective

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To determine the direct medical costs of treating lower respiratory tract infections (LRTIs) in a managed care organization (MCO).

Study Design

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Retrospective analysis of a regional MCO identifying adults diagnosed with acute exacerbation of chronic bronchitis (AECB) or community- acquired pneumonia (CAP).

Methods

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A claims database examination of International Classification of Diseases, Ninth Revision, Clinical Modification codes was conducted to identify adults receiving initial outpatient care for an LRTI during 2005-2006. Medical record review then was conducted to verify clinical diagnosis of AECB or CAP. Clinical and demographic data were collected. Outpatient office and clinic visits, hospitalization, and radiology, pathology, and pharmacy records were used to determine treatment costs. Treatment failure was determined by use of a second antibiotic course, follow-up emergency room presentation, or hospitalization for LRTI within 28 days of the index visit. The primary outcome was per-case treatment cost from the payer perspective.

Results

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Clinical diagnosis was confirmed for 65 unique coded visits (60 patients; 39 with AECB, 22 with CAP; 1 in both cohorts). Initial visit, initial diagnostic testing, and subsequent hospitalization accounted for the majority (63%) of payer costs. Antibiotics were responsible for 15% of payer costs. Higher initial antibiotic expenditure in the AECB cohort yielded a cost-benefit ratio of 3:1. Mean per-case costs for success and failure were $277 & $372 for AECB, and $493 & $3019 for CAP, respectively.

Conclusions

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Initial visit and hospitalization costs contribute the majority of payer expenditure while antibiotic expenditure incurs a nominal burden. Higher expenditure on initial antibiotic therapy in the AECB population appears to be beneficial.

(Am J Manag Care. 2008;14(4):190-196)

Direct medical costs of acute exacerbation of chronic bronchitis (AECB) or community-acquired pneumonia (CAP) in an adult primary care population were determined from a managed care perspective.

Compared with other costs of treatment, expenditures for antibiotics were nominal.

Clinical failure cost substantially more than success in cases of both AECB and CAP.

Identification of the component costs associated with outpatient treatment of lower respiratory tract infections (LRTIs) will influence ongoing research to establish the clinical and economic continuum of LRTIs, ultimately advancing clinical and policy decision making.

Epidemiological data from the 1980 National Medical Care Utilization and Expenditure Survey indicated that acute respiratory tract infections were responsible for approximately 5% of the total charges for all healthcare services in the United States.¹ Lower respiratory tract infection (LRTI) occurred in only 4% of the population (vs 50% for upper respiratory tract infection), yet was responsible for 42% of the economic burden for acute respiratory tract infection. These charges were primarily attributable to hospitalization (74.1%), followed by physician visits (21.4%) and medications (2.7%).¹ Previous analyses identifying hospitalization costs for LRTI have comprehensively established total and component costs (inpatient services, length of stay, medication, and physician costs) of inpatient management.^2-6 However, few analyses identify outpatient LRTI costs; these costs have been less rigorously evaluated, and no study has adequately established the contributions of each treatment component to total cost.^2,3,6,7

The expanding economic burden of LRTIs, encompassing increased healthcare access, advancing diagnostic technology, and new antibiotics, presents ongoing challenges for payers searching for cost-saving opportunities. Extrapolating from the 1980 National Medical Care Utilization and Expenditure Survey by applying medical consumer pricing for 2006, LRTIs would cost $8.9 billion annually.^1,8 However, in more recent analyses, acute exacerbation of chronic bronchitis (AECB) and community-acquired pneumonia (CAP) were found to cost $1.96 billion and $11.21 billion, respectively, in 2006 dollars for a total of $13.17 billion.^2,3 Clearly, emergence of the aforementioned expansions in healthcare access, technology, and antibiotics have increased healthcare costs and likely shifted payer costs toward outpatient expenditure. However, the extent to which each cost category (eg, initial and follow-up antibiotics, initial and follow-up visits, diagnostics, hospitalizations) contributes to total payer costs is not well described. Accordingly, a claims database analysis of a regional managed care organization (MCO) covering 38,278 adult lives was conducted to identify total and component treatment costs of AECB and CAP.

METHODS

Table 1

From the database of 38,278 adults, 8861 patients were identified by 70 ICD-9-CM diagnostic codes pertaining to respiratory illness. We determined that 10 ICD-9-CM codes would identify patients with the greatest potential to meet general inclusion and diagnostic criteria, resulting in 363 patients and 432 cases of LRTI. Of the 432 initial outpatient visits coded for AECB or CAP, 65 cases were validated from the electronic medical records. These comprised 60 patients; 43 cases of AECB in 39 patients and 22 cases of CAP in 22 patients; 1 patient was included in both the AECB and CAP cohorts (Figure 1). shows patient demographics, antibiotic history, and concomitant conditions for the 60 patients included in the study, categorized by AECB or CAP. Antibiotic utilization within the previous 3 months occurred in nearly 50% of the patients with LRTI; fluoroquinolones, β-lactams, macrolides, and sulfamethoxazole/trimethoprim were most frequently prescribed. The most frequently encountered concomitant conditions were COPD, tobacco utilization, asthma, home oxygen, and diabetes mellitus. Antibiotic prescribing at the index visit was largely consistent with guidelines, as quinolones, macrolides, and β- lactams were the most frequently prescribed classes.^15-17 Apparent success in the AECB cohort was seen in 38 of 43 cases (88.4%). Among the 34 patients with AECB who received an antibiotic (79%), the success rate was 94%. Notably, 9 patients with AECB (21%) did not receive an antibiotic despite ICD-9-CM identification and clinical documentation sufficient to indicate acute exacerbation. The 67% success rate for these patients was less than that observed in the antibiotic-treated patients (P = .022). All patients in the CAP cohort received an antibiotic; the success rate was 81.8%. Quinolones were prescribed the most frequently, followed by macrolides and β-lactams.

DISCUSSION

To our knowledge, this is the first study that combines ICD-9-CM codes and clinically verified cumulative and component resource utilization to assess successful and failed management of AECB and CAP in an outpatient population. Payer costs for LRTI averaged $513 per case ($288 AECB; $953 CAP). Successfully managed CAP costs approximately twice as much as does successfully managed AECB. Clinical failure costs substantially more than success in cases of both AECB and CAP. Initial visit and diagnostic tests, and hospitalizations contributed the greatest proportion of payer expenditure, followed by follow-up visits and diagnostics, and last by antibiotic therapy. A lower-than-anticipated frequency of hospitalization suggests there are likely higher per-case failure and differential outcome costs than those observed in our study sample; increased frequency of hospitalization would increase total costs and further diminish antibiotic contribution to total payer burden. It appears that there could be significant benefit in establishing a continuum that incorporates bacterial identification, antibiotic selection, and early and late treatment outcomes in the outpatient and inpatient settings to correlate with observed direct medical component costs. The establishment of such a continuum may serve to corroborate observations that favor greater initial antibiotic expenditure in the AECB population and to enable evaluation of the pharmacoeconomic impact of bacteriologic and clinical outcomes in the comprehensive management of LRTI.

Author Affiliations: From CPL Associates, LLC, Amherst, NY (SVM, JJS, JAP); and the University of Buffalo, Buffalo, NY (NMP, EMS).

Author Disclosure: The authors (SVM, NMP, EMS) report no relationship or financial interest with any entity that would pose a conflict of interest with the subject matter of this article. Dr Schentag consults for Sanofi-Aventis, Oscient, Wyeth, King Pharmaceuticals, Schering Plough, Nektar Therapeutics, and Bayer Corporation. Dr Paladino consults, receives grant support, and/or is a member of the speaker’s bureau for Bayer, Cubist, Elan, Forest, Optimer, Ortho-McNeil, Sanofi-Aventis, Schering Plough, and Wyeth.

Funding Source: None.

Authorship Information: Concept and design (SVM, JJS, JAP); acquisition of data (SVM, EMS); analysis and interpretation of data (SVM, NMP, EMS, JAP); drafting of the manuscript (SVM, NMP, EMS, JJS, JAP); critical revision of the manuscript for important intellectual content (SVM, NMP, EMS, JJS, JAP); statistical analysis (SVM); provision of study materials or patients (SVM); administrative, technical, or logistic support (SVM, EMS, JAP); and supervision (SVM, NMP, EMS, JAP).

Address Correspondence to: Scott V. Monte, PharmD, CPL Associates, LLC, 3980 Sheridan Dr, Amherst, NY 14226. E-mail: smonte@cplassociates.com.

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