Original ArticleVeteran's affairs hospital discharge databases coded serious bacterial infections accurately
Introduction
The use of immunomodulatory drugs for inflammatory and neoplastic conditions has increased and will continue to do so. For many conditions, such medications provide important new therapeutic advances, but this must be balanced against the potential for adverse effects, including serious infections. While common side effects may be detected in the setting of randomized controlled trials, less frequent events that may only occur in subsets of patients will not be reliably detected in premarketing trials [1], [2], [3], [4], [5]. The recently reported cases of tuberculosis in patients using TNF-α antagonists demonstrate the importance of thorough postmarketing surveillance [6].
Health care utilization databases represent an important tool for postmarketing surveillance. Such databases reflect routine care, are available with little delay, and often cover large populations for an efficient surveillance of rare outcomes [7]. In addition, patients not included in randomized trials but frequent users of immunomodulatory drugs, particularly elderly patients, are represented in such databases.
Biologic disease modifying antirheumatic drugs (DMARDs) for rheumatoid arthritis are now among the most widely selling biologic immunomodulating drugs [8], [9]. The use of TNF-α blocking agents increased sharply in the past 5 years and is expected to continue to expand. As noted above, there are a number of case reports that suggest that TNF-α blocking agents may increase the risk of serious bacterial and opportunistic infections [10], [11], [12], [13], [14], [15], [16], [17]. These infections come with a substantial burden of disease and are of considerable public health relevance even if the absolute number of cases may be small.
Since the expected absolute number of serious bacterial or opportunistic infections in subgroups of DMARD categories is too small to be reliably studied in randomized trials, the safety of these drugs is most efficiently studied in large health care utilization databases. We sought to test the accuracy of health care utilization databases to identify serious bacterial infections and opportunistic infections that lead to hospital admissions.
Section snippets
Data sources
The Department of Veterans Affairs (VA) administrative database of the New England region (VISN I) was used to identify patients with serious bacterial infections and opportunistic infections using ICD-9-CM diagnostic codes from hospital discharge files. The database contains administrative information on all hospitalizations within the New England VA system for administrative purposes. Data completeness for hospital admissions is thought to be close to 100% and coding of discharge diagnoses
Results
A total of 158 patients who were hospitalized for the selected bacterial infections were identified in the database and 69 patients for opportunistic infections. The average age was 69.6 years and 98.6% of patients were male. Table 1 lists the number of patients identified for each infectious condition.
The PPV of the identified ICD-9-CM codes in predicting our gold-standard definition of specific bacterial infections that lead to hospital admissions varied between 100% and 66%. All conditions
Discussion
Our study evaluated the PPVs of ICD-9-CM codes for serious bacterial and opportunistic infections leading to hospital admissions using health care utilization data. The condition-specific PPVs were in a range comparable to many other outcomes frequently used in database studies. If the gold-standard definitions were relaxed to any infectious condition that led to the index hospitalization, the PPV for bacterial infections increased to 90%, which is considered high and compares to many other
Acknowledgments
This study was funded by the Engalitcheff Arthritis Outcomes Initiative through the Arthritis Foundation.
References (20)
- et al.
Infliximab (chimeric anti-tumour necrosis factor alpha monoclonal antibody) versus placebo in rheumatoid arthritis patients receiving concomitant methotrexate: a randomised phase III trial. ATTRACT Study Group
Lancet
(1999) - et al.
A review of uses of health care utilization databases for epidemiologic research on therapeutics
J Clin Epidemiol
(2005) - et al.
Immunosuppression: evolution in practice and trends, 1993–2003
Am J Transplant
(2005) The treatment of rheumatoid arthritis
Best Pract Res Clin Rheumatol
(2004)- et al.
Fatal sepsis in a patient with rheumatoid arthritis treated with etanercept
Mayo Clin Proc
(2001) - et al.
Anti-tumor necrosis factor agents and tuberculosis risk: mechanisms of action and clinical management
The Lancet Infectious Diseases
(2003) - et al.
The accuracy of Medicare claims-based diagnosis of acute myocardial infarction: estimating positive predictive value based on review of hospital records
Am Heart J
(2004) - et al.
Infliximab and methotrexate in the treatment of rheumatoid arthritis. Anti-Tumor Necrosis Factor Trial in Rheumatoid Arthritis with Concomitant Therapy Study Group
N Engl J Med
(2000) - et al.
A trial of etanercept, a recombinant tumor necrosis factor receptor: Fc fusion protein, in patients with rheumatoid arthritis receiving methotrexate
N Engl J Med
(1999) - et al.
Etanercept therapy in rheumatoid arthritis. A randomized, controlled trial
Ann Intern Med
(1999)
Cited by (138)
Pre-admission and In-Hospital Statin Use is Associated With Reduced Short-Term Mortality in Infective Endocarditis
2023, Mayo Clinic ProceedingsPeripheral Artery Disease and Subsequent Risk of Infectious Disease in Older Individuals: The ARIC Study
2022, Mayo Clinic ProceedingsAssociation Between Volume and Outcomes of Infective Endocarditis Surgery: A Nationwide Cohort Study
2022, Annals of Thoracic Surgery