Prevalence of Bacteremia in Pediatric Patients With CAP
Prevalence of Bacteremia in Pediatric Patients With CAP
This multicenter retrospective study was conducted from a cohort of children evaluated to validate International Classification of Diseases, 9th revision, Clinical Modification codes for CAP. The previous study used billing codes from the Pediatric Hospital Information System (Children's Hospital Association, Overland Park, KS) and included patients from 60 days to 18 years of age, with a discharge code of pneumonia or effusion, radiographically confirmed pneumonia and/or clinical features and laboratory results consistent with pneumonia from 1 of 4 free-standing children's hospitals (Monroe Carell Jr. Children's Hospital at Vanderbilt, Nashville, TN; Children's Mercy Hospitals & Clinics, Kansas City, MO; Seattle Children's Hospital, Seattle, WA and Cincinnati Children's Hospital Medical Center, Cincinnati, OH) from January 1, 2010, to December 31, 2010. A 25% random sample (N = 998) of 3646 hospital discharges were identified as possible CAP by International Classification of Diseases, 9th revision, Clinical Modification codes and were selected for medical record review. Patients hospitalized since birth, with a chronic comorbid condition or whose primary admitting diagnosis was trauma, were excluded (n = 243). In addition, patients were excluded if no blood culture information was available (n = 19) or there was no provider diagnosis of pneumonia (n = 78). Patients meeting inclusion criteria were categorized into 3 mutually exclusive categories: those with documented bacteremia, those without bacteremia as documented by a negative or contaminated blood culture (culture negative) and those in whom a blood culture had not been performed (no culture). All culture data were obtained within 48 hours of hospital admission.
Detailed medical record reviews were performed in all children in this study. Data collected included demographics, presenting signs and symptoms, physical examination findings and laboratory, radiograph, and microbiology results, including bacterial pathogens and antibiotic susceptibility patterns. The following clinical outcomes were also recorded: length of stay, presence of pneumonia-associated sequelae, supplemental oxygen requirement, intensive care unit admission and vasoactive medications. Treatment data during hospitalization were obtained from Pediatric Hospital Information System and discharge antibiotic therapy was obtained from medical record review. Data from medical record review were entered into a central web-based data collection system. All investigators who participated in medical record review underwent training and piloted the record review process to ensure consistency in data collection. Discrepancies were resolved by group consensus and changes were made to the data collection tool for clarification when necessary.
Pathogenic bacteria included S. pneumoniae, Staphylococcus aureus andHaemophilus influenzae. Bacteria considered as contaminants included coagulase-negative Staphylococcus spp., [alpha]-hemolytic Streptococcus spp.,Corynebacterium spp., Bacillus spp. and Micrococcus spp. Susceptibility data were determined at each individual site using current Clinical and Laboratory Standards Institute criteria. Antimicrobial therapy was recorded daily and defined in 2 categories: narrow (penicillin or aminopenicillin) and broad (any second- or third-generation cephalosporin, macrolide, lincosamide, quinolone or penicillin combined with a [beta]-lactamase inhibitor). Blood culture–directed changes in antibiotics were classified as broadened, narrowed or unchanged relative to S. pneumoniae and Staphylococcus aureus. For example, a patient initially receiving vancomycin that was changed to ceftriaxone based on culture results was classified as "narrowed" due to a narrower spectrum of pneumococcal andStaphylococcus aureus coverage of ceftriaxone compared with vancomycin. Conversely, if ceftriaxone was added to vancomycin with a blood culture result revealing either S. pneumoniae or Staphylococcus aureus, therapy was considered to be unchanged based on no additional spectrum coverage of either pathogen.
Pneumonia was categorized as uncomplicated or complicated within the first 24 hours of hospitalization. Uncomplicated pneumonia was defined as alveolar or lobar infiltrate with or without a small effusion on chest radiograph or was determined to be clinically consistent with pneumonia in the medical record. Complicated pneumonia was defined as at least 1 of the following: presence of moderate-to-large pleural effusion, lung abscess or necrosis, or bronchopleural fistula on radiologic imaging (eg, chest radiograph, ultrasound, computerized axial tomography scan) or requirement of a pleural fluid drainage procedure. Pneumonia sequelae were defined as presence of one or more of the following: complicated pneumonia, organ dysfunction, vasoactive support, intensive care admission or extrapulmonary complication. Organ dysfunction was based on consensus guidelines and defined as sepsis evidenced by bacteremia in the setting of intensive care admission requiring vasoactive medications, respiratory failure with the need for endotracheal intubation or noninvasive mechanical ventilation via positive pressure methods or dysfunction in cardiovascular, renal, hepatic, hematologic or neurologic systems. Metastatic complication was defined as at least 1 of the following sites of secondary infection: skin/soft tissue abscess, pyomyositis, septic arthritis or osteomyelitis at any time during hospitalization.
Characteristics of the study population were described overall and within their blood culture group. Continuous variables were summarized using median and interquartile range (IQR) and compared between children with bacteremia, those with negative blood culture and without blood culture using the Wilcoxon rank-sum test. Categorical variables were described using counts and frequencies and compared between those with bacteremia and those with negative culture and no culture using χ test or Fisher's exact test. The prevalence of bacteremia and contaminated blood cultures was determined for all patients, patients with uncomplicated pneumonia and patients with complicated pneumonia using binomial exact 95% confidence intervals. Descriptive statistics were used for susceptibility data and therapy at hospital discharge.
Materials and Methods
Study Design, Setting and Participants
This multicenter retrospective study was conducted from a cohort of children evaluated to validate International Classification of Diseases, 9th revision, Clinical Modification codes for CAP. The previous study used billing codes from the Pediatric Hospital Information System (Children's Hospital Association, Overland Park, KS) and included patients from 60 days to 18 years of age, with a discharge code of pneumonia or effusion, radiographically confirmed pneumonia and/or clinical features and laboratory results consistent with pneumonia from 1 of 4 free-standing children's hospitals (Monroe Carell Jr. Children's Hospital at Vanderbilt, Nashville, TN; Children's Mercy Hospitals & Clinics, Kansas City, MO; Seattle Children's Hospital, Seattle, WA and Cincinnati Children's Hospital Medical Center, Cincinnati, OH) from January 1, 2010, to December 31, 2010. A 25% random sample (N = 998) of 3646 hospital discharges were identified as possible CAP by International Classification of Diseases, 9th revision, Clinical Modification codes and were selected for medical record review. Patients hospitalized since birth, with a chronic comorbid condition or whose primary admitting diagnosis was trauma, were excluded (n = 243). In addition, patients were excluded if no blood culture information was available (n = 19) or there was no provider diagnosis of pneumonia (n = 78). Patients meeting inclusion criteria were categorized into 3 mutually exclusive categories: those with documented bacteremia, those without bacteremia as documented by a negative or contaminated blood culture (culture negative) and those in whom a blood culture had not been performed (no culture). All culture data were obtained within 48 hours of hospital admission.
Data Source
Detailed medical record reviews were performed in all children in this study. Data collected included demographics, presenting signs and symptoms, physical examination findings and laboratory, radiograph, and microbiology results, including bacterial pathogens and antibiotic susceptibility patterns. The following clinical outcomes were also recorded: length of stay, presence of pneumonia-associated sequelae, supplemental oxygen requirement, intensive care unit admission and vasoactive medications. Treatment data during hospitalization were obtained from Pediatric Hospital Information System and discharge antibiotic therapy was obtained from medical record review. Data from medical record review were entered into a central web-based data collection system. All investigators who participated in medical record review underwent training and piloted the record review process to ensure consistency in data collection. Discrepancies were resolved by group consensus and changes were made to the data collection tool for clarification when necessary.
Study Definitions
Pathogenic bacteria included S. pneumoniae, Staphylococcus aureus andHaemophilus influenzae. Bacteria considered as contaminants included coagulase-negative Staphylococcus spp., [alpha]-hemolytic Streptococcus spp.,Corynebacterium spp., Bacillus spp. and Micrococcus spp. Susceptibility data were determined at each individual site using current Clinical and Laboratory Standards Institute criteria. Antimicrobial therapy was recorded daily and defined in 2 categories: narrow (penicillin or aminopenicillin) and broad (any second- or third-generation cephalosporin, macrolide, lincosamide, quinolone or penicillin combined with a [beta]-lactamase inhibitor). Blood culture–directed changes in antibiotics were classified as broadened, narrowed or unchanged relative to S. pneumoniae and Staphylococcus aureus. For example, a patient initially receiving vancomycin that was changed to ceftriaxone based on culture results was classified as "narrowed" due to a narrower spectrum of pneumococcal andStaphylococcus aureus coverage of ceftriaxone compared with vancomycin. Conversely, if ceftriaxone was added to vancomycin with a blood culture result revealing either S. pneumoniae or Staphylococcus aureus, therapy was considered to be unchanged based on no additional spectrum coverage of either pathogen.
Pneumonia was categorized as uncomplicated or complicated within the first 24 hours of hospitalization. Uncomplicated pneumonia was defined as alveolar or lobar infiltrate with or without a small effusion on chest radiograph or was determined to be clinically consistent with pneumonia in the medical record. Complicated pneumonia was defined as at least 1 of the following: presence of moderate-to-large pleural effusion, lung abscess or necrosis, or bronchopleural fistula on radiologic imaging (eg, chest radiograph, ultrasound, computerized axial tomography scan) or requirement of a pleural fluid drainage procedure. Pneumonia sequelae were defined as presence of one or more of the following: complicated pneumonia, organ dysfunction, vasoactive support, intensive care admission or extrapulmonary complication. Organ dysfunction was based on consensus guidelines and defined as sepsis evidenced by bacteremia in the setting of intensive care admission requiring vasoactive medications, respiratory failure with the need for endotracheal intubation or noninvasive mechanical ventilation via positive pressure methods or dysfunction in cardiovascular, renal, hepatic, hematologic or neurologic systems. Metastatic complication was defined as at least 1 of the following sites of secondary infection: skin/soft tissue abscess, pyomyositis, septic arthritis or osteomyelitis at any time during hospitalization.
Statistical Analysis
Characteristics of the study population were described overall and within their blood culture group. Continuous variables were summarized using median and interquartile range (IQR) and compared between children with bacteremia, those with negative blood culture and without blood culture using the Wilcoxon rank-sum test. Categorical variables were described using counts and frequencies and compared between those with bacteremia and those with negative culture and no culture using χ test or Fisher's exact test. The prevalence of bacteremia and contaminated blood cultures was determined for all patients, patients with uncomplicated pneumonia and patients with complicated pneumonia using binomial exact 95% confidence intervals. Descriptive statistics were used for susceptibility data and therapy at hospital discharge.
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