Methods: We identified patients with ≥1 inpatient ICD-9 codes consistent with CAP after VACS enrollment. Chart reviews used standardized data abstraction forms. Events were categorized as CAP present or not on admission and microbiologic diagnosis as definitive, presumed, or suspected. Positive predictive value (PPV) was calculated as the number of chart review confirmed pneumonia events divided by the number identified by ICD-9 codes.
Results: Between 2003-08, of 434 HIV+ and 115 HIV- patients with a CAP ICD-9 code, 74% and 66%, respectively, had pneumonia confirmed by chart review, 18% and 25% had no pneumonia, 2% and 4% had hospital-acquired pneumonia, and 6% and 4% were uncertain (p=0.1); 9% of HIV+ and 18% of HIV- confirmed CAP cases had HCAP risk factors (P=0.018). PPV of ICD-9 codes ranged from 0-100%; it was 74% for the most frequent code (pneumonia due to organism unspecified). Indeed, the majority of CAP patients had suspected bacterial pneumonia (BP) without microbiologic confirmation; only in 13% and 5% of HIV+ and HIV- was a definitive BP diagnosis established based on identification of a pathogen, and in 8% and 9%, respectively, the diagnosis was presumed based on compatible gram stain and culture results from expectorated or induced sputum, or from endotracheal aspirate (P=0.3).
Conclusion: Overall, 72% of patients with a CAP ICD-9 code had clinically confirmed pneumonia by chart review, a definitive microbiologic diagnosis of BP was infrequently established. HIV- patients were more likely to have HCAP. In this cohort, ICD-9 codes for CAP perform similarly in HIV+ and HIV- patients, and identified patients with clinically confirmed CAP requiring hospitalization with good reliability. Future work will assess modified algorithms to improve PPV of ICD-9 codes to identify patients with CAP.
M. C. Rodriguez-Barradas,
S. Brown, None
A. Butt, Gilead: Grant Investigator , Research grant
AbbVie: Grant Investigator , Research grant
M. J. Fine, None
M. Bidwell Goetz, None
C. Graber, None
L. Huang, None
K. Mcginnis, None
D. Rimland, None
A. C. Justice, None
K. Crothers, None