Elsevier

Vaccine

Volume 29, Issue 18, 18 April 2011, Pages 3398-3412
Vaccine

Healthcare utilization and cost of pneumococcal disease in the United States

https://doi.org/10.1016/j.vaccine.2011.02.088Get rights and content

Abstract

Background

Streptococcus pneumoniae continues to cause a variety of common clinical syndromes, despite vaccination programs for both adults and children. The total U.S. burden of pneumococcal disease is unknown.

Methods

We constructed a decision tree-based model to estimate U.S. healthcare utilization and costs of pneumococcal disease in 2004. Data were obtained from the 2004–2005 National (Hospital) Ambulatory Medical Care Surveys (outpatient visits, antibiotics) and the National Hospital Discharge Survey (hospitalization rates), and CDC surveillance data. Other assumptions regarding the incidence of each syndrome due to pneumococcus, expected health outcomes, and healthcare utilization were derived from literature and expert opinion. Healthcare and time costs used 2007 dollars.

Results

We estimate that, in 2004, pneumococcal disease caused 4.0 million illness episodes, 22,000 deaths, 445,000 hospitalizations, 774,000 emergency department visits, 5.0 million outpatient visits, and 4.1 million outpatient antibiotic prescriptions. Direct medical costs totaled $3.5 billion. Pneumonia (866,000 cases) accounted for 22% of all cases and 72% of pneumococcal costs. In contrast, acute otitis media and sinusitis (1.5 million cases each) comprised 75% of cases but only 16% of direct medical costs. Patients ≥65 years old, accounted for most serious cases and the majority of direct medical costs ($1.8 billion in healthcare costs annually). In this age group, pneumonia caused 242,000 hospitalizations, 1.4 million hospital days, 194,000 emergency department visits, 374,000 outpatient visits, and 16,000 deaths. However, if work loss and productivity are considered, the cost of pneumococcal disease among younger working adults (18–<50) nearly equaled those ≥65.

Conclusions

Pneumococcal disease remains a substantial cause of morbidity and mortality even in the era of routine pediatric and adult vaccination. Continued efforts are warranted to reduce serious pneumococcal disease, especially adult pneumonia.

Introduction

Streptococcus pneumoniae (pneumococcus) is a major cause of bacterial disease in children and adults. Its clinical spectrum includes localized disease such as acute otitis media (AOM) and sinusitis, and more serious infections such as pneumonia and meningitis, which cause substantial morbidity and mortality. Because of this, pneumococcal vaccines have been long recommended for widespread use.

The 23-valent pneumococcal polysaccharide vaccine was licensed in 1983 and is 50–85% effective in preventing invasive pneumococcal disease (IPD) among healthy adults [1], [2]. The U.S. licensure of a pediatric 7-valent pediatric conjugate vaccine (PCV7) in 2000, led to a 4-fold decrease in the IPD rate among children <5 years old [3], and a decrease in the IPD rate among adults >50 years old of nearly one-third [4], [5]. Uptake of PCV7 vaccine has been high (>90%) given the addition of this vaccine to the routine pediatric vaccine schedule [6], [7].

Nevertheless, despite extensive vaccination programs, pneumococcus remains a common human pathogen. Surveillance from the Centers for Disease Control and Prevention (CDC) suggests that post-PCV7 reductions in invasive disease plateaued by 2004, with non-vaccine serotypes causing the remaining IPD [4], [8], [9], [10], [11]. Other pneumococcal diseases such as AOM and non-invasive pneumonia have declined modestly [12], [13], but are more common than IPD and are important drivers of healthcare utilization and related costs. Thus, the burden of pneumococcal disease may still be considerable in the current vaccine era [14]. Robust estimates of this burden may help drive further prevention strategies. Currently, only 64% of adults ≥65 and 37% of adults with diabetes aged 18–64 are vaccinated [15], [16].

Pneumococcal disease burden has been estimated in other countries [17], [18]. We sought to estimate U.S. healthcare utilization and costs for IPD and non-invasive pneumococcal infections to identify population targets to reduce pneumococcal disease, and quantify the potential savings of further prevention efforts, such as future vaccines covering non-PCV7 serotypes.

Section snippets

Methods

We developed a decision tree-based model to estimate U.S. healthcare utilization, outcomes, and costs attributable to pneumococcal disease in 2004. We used the most recently available national healthcare utilization and cost data, data from the CDC's Active Bacterial Core Surveillance (ABCs) system, existing literature, and expert panel opinion to inform parameter values (Appendix A Model parameters and sources, Appendix B Outpatient model parameters: incidence and healthcare utilization,

Results

In 2004, pneumococcus caused an estimated 4.0 million disease episodes (Table 2). Over 3.5 million were seen in outpatient settings only, with AOM and sinusitis responsible for 85% of outpatient cases (1.5 million cases each). Of the 445,000 pneumococcal-related hospitalizations, >90% were for pneumonia. All results are rounded to the nearest thousand, or first significant digit if less than a thousand. Slight differences may occur in reported numbers due to rounding.

Comment

S. pneumoniae continues to be responsible for a large disease burden in the U.S. despite introduction of routine childhood pneumococcal vaccination in 2000 and availability of polysaccharide vaccine since 1983. The estimated 4 million cases and $3.5 billion in direct medical costs in 2004 has likely remained stable through 2008 since overall rates of disease have not increased despite modest increases in non-PCV7 serotypes [25]. Introduction of a 13-valent pneumococcal conjugate vaccine (PCV13)

Acknowledgments

We are grateful to the following expert panel members for their time and expertise provided to this project: Dr. Steven Black, Dr. Ralph Gonzales, Dr. Marie Griffin, Dr. Keith Klugman, Dr. Katherine O’Brien, Dr. Lionel Mandel, and Dr. Daniel Musher. We would also like to thank Dr. Antonio Anzueto and Dr. Peter Lindenhauer, and Sara Schoenfeld for their contributions, as well as Dr. Mark Messonnier for advice on economic methods.

This study was funded by a grant from the CDC (TS-1363,

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