Disclosures Assessing Septic Arthritis Outcomes and Prognostic Factors in Culture Positive and Culture Negative Patients � I have nothing to disclose Shaina Lipa, MS4 UCSF SOM PROF-PATH Research Fellow PI - Dr. Saam Morshed, MD, PhD Study Questions Background/Significance � Septic arthritis is a clinical emergency that may 1. Are there risk factors for culture positivity for cause substantial morbidity and mortality patients presenting with septic arthritis? � Diagnosis is confirmed by gram stain and culture 1. Are there differences in outcomes between of joint aspiration patients with culture positive septic arthritis versus those with culture negative septic � Up to 40% of patients may have negative cultures arthritis? � Presently there are not enough studies that evaluate the difference in complication rates between culture positive and culture negative patients
Study Design and Methods Study Design and Methods � Inclusion criteria: � Study subjects were identified based on a query of the THREDS (The Health Record Data Service) database for – Adult patients (18 or older) who presented with septic the following: arthritis in a large joint between May 2008-May 2012 – ED visits, admissions, or outpatient clinic visits between – Patients with intra-articular aspirate white cell count (WCC) of at lest 50,000 mm 3 May 2008 to May 2012 – ICD9 codes 711.00-711.99, 274.00, 274.01, and 274.9 � Exclusion criteria: – Any patients with septic arthritis who are younger than ICD 9 Code Description 18 years old will not be selected for the cohort 711.00-711.99 Arthropathy associated with infections, all joints 274.00 Gouty arthropathy, joint 274.01 Acute gouty arthropathy 274.9 Gout, unspecified Study Design and Methods Study Design and Methods 2,437 2,437 THREDS THREDS 1,817 no culture 81 81 Met Criteria Met Criteria 49 32 49 32 Culture Positive Culture Negative Culture Positive Culture Negative
Study Design and Methods Risk Factors � Demographics 2,437 � Health-related behaviors THREDS 1,817 no culture � Clinical features 534 <50,000 WCC 81 � Joint factors Met Criteria � Medical comorbidities � Distant site infections 49 32 Culture Positive Culture Negative Outcomes Outcomes � Number of procedures performed for � Surgical procedures > 1 septic arthritis � Re-admission to the hospital � Number of re-admissions to the � Incidence of osteomyelitis hospital � Admission to ICU � Incidence of osteomyelitis � Length of stay � Admission to ICU � Length of stay = Composite Outcome
Statistical Analysis Results � Hypothesis #1: There are prognostic factors for Culture Positive Culture Negative Joint culture positivity in septic arthritis patients n (%) n (%) Knee 31 (63) 23 (72) Ankle 6 (12) 4 (13) Elbow 4 (8) 4 (13) � Hypothesis #2: There are differences in Hip 4 (8) 0 complication rates between culture positive and Shoulder 3 (6) 0 culture negative septic arthritis patients Wrist 1 (2) 1 (3) Results Results Significant Factors from Bivariable Analysis (P </ 0.2) Culture Positive Culture Negative Pathogen Frequency (%) Risk Factor P-value (n=49) (n=32) Bacteroides non-fragilis group 1 (2) Demographics Coagulase negative Staphylococcus 1 (2) Sex 0.126 Escherichia coli 1 (2) Male 39 20 Group B Streptococcus 3 (6) Female 10 12 Health Related Behaviors Group A Streptococcus 4 (8) Group G Streptococcus 1 (2) Alcohol 21 7 0.060 Klebsiella pneumoniae 1 (2) Injection Drug Use 12 2 0.039 MRSA 13 (27) Lab Data MSSA 18 (38) 130181 (107894) 90689 (53055) Synovial Fluid WCC 0.056 Neisseria gonorrhoeae 1 (2) Positive Blood Culture 16 0 0.000 Pseudomonas aeruginosa 1 (2) 13.9 (6.2) 11.4 (3.8) WBC 0.052 Streptococcus pneumoniae 3 (6) 130.8 (66.4) 103.7 (71.0) CRP 0.131 Standard deviations are provided in parenthesis
Results Results Significant Factors from Bivariable Analysis (P >/ 0.2) Culture Positive Culture Negative � Receiver Operating Risk Factor P-value (n=49) (n=32) Characteristic (ROC ) Local curve Prosthetic Joint 4 0 0.149 Prior Joint Surgery 12 0 0.002 � Maximized sensitivity Medical Comorbidities and specificity Diabetes Meillitus 6 10 0.047 Hepatits C 18 4 0.021 � Found WBC of 13 to Liver Disease 6 0 0.076 be our cut-point Distant Site Infections Remote Bone Infection 6 0 0.076 Results Results Multivariate Analysis for Culture Positivity Multivariate Analysis for Procedure Factor Odds Ratio P-value 95% CI Factor Odds Ratio P-value 95% CI Culture positivity Procedure Alcohol 6.7 0.041 1.1-42.0 Culture positivity 17.4 0.008 2.1-144.2 Injection drug use 36.0 0.003 3.3-389.9 Osteoarthritis 0.2 0.153 0.0-1.9 Serum WBC >/13 10.2 0.021 1.4-74.1 Synovial WCC 1.0 0.154 0.9-1.0
Results Results Multivariate Analysis for Readmission Multivariate Analysis for Composite Outcome Factor Odds Ratio P-value 95% CI Factor Odds Ratio P-value 95% CI Readmission Composite Culture positivity 0.53 0.609 0.05-6.06 Culture positivity 20.51 0.002 3.06-137.40 Antibiotics beforehand 24.71 0.020 1.66-367.35 Age 1.05 0.053 1.00-1.11 HepC 6.44 0.059 0.93-44.33 Chills 0.17 0.041 0.03-0.93 Smoking 3.97 0.161 0.58-27.28 HepC 4.50 0.049 1.00-20.16 Alcohol 8.95 0.030 1.23-64.96 Antibiotics beforehand 30.42 0.025 1.55-597.27 Summary Acknowledgements � Dr. Saam Morshed, MD, PhD IDU and alcohol users were more likely to be culture positive � � Orthopaedic Trauma Institute Patients with a serum WBC of 13 k/ µ L or greater were more likely to � Hannah Canty, MS2 � be culture positive � Ethan Canty � Steven Kwong, MS2 Culture positive patients were more likely to experience an adverse � outcome � Monica Fernandez � Dr. Alicia Fernandez, MD Patients with culture positivity are a particular high-risk population in � � PROF-PATH Fellowship whom interventions need to be focused to improve outcomes � CTR Pathway Patients who are IDU, alcohol users, or patients with a serum WBC of � 13 k/ µ L or greater may be particularly prone to more severe joint sepsis and may require more aggressive treatment to mitigate adverse outcomes
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