Disclosures Assessing Septic Arthritis Outcomes and Prognostic - - PowerPoint PPT Presentation

Assessing Septic Arthritis Outcomes and Prognostic Factors in Culture Positive and Culture Negative Patients

Shaina Lipa, MS4 UCSF SOM PROF-PATH Research Fellow PI - Dr. Saam Morshed, MD, PhD

Disclosures

I have nothing to disclose

Study Questions

• 1. Are there risk factors for culture positivity for

patients presenting with septic arthritis?

• 1. Are there differences in outcomes between

patients with culture positive septic arthritis versus those with culture negative septic arthritis?

Background/Significance

Septic arthritis is a clinical emergency that may

cause substantial morbidity and mortality

Diagnosis is confirmed by gram stain and culture

• f joint aspiration

Up to 40% of patients may have negative cultures Presently there are not enough studies that

evaluate the difference in complication rates between culture positive and culture negative patients

Study Design and Methods

Inclusion criteria:

– Adult patients (18 or older) who presented with septic arthritis in a large joint between May 2008-May 2012 – Patients with intra-articular aspirate white cell count (WCC) of at lest 50,000 mm3

Exclusion criteria:

– Any patients with septic arthritis who are younger than 18 years old will not be selected for the cohort

Study Design and Methods

Study subjects were identified based on a query of the

THREDS (The Health Record Data Service) database for the following: – ED visits, admissions, or outpatient clinic visits between May 2008 to May 2012 – ICD9 codes 711.00-711.99, 274.00, 274.01, and 274.9

ICD 9 Code Description 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

2,437

THREDS

81

Met Criteria

49

Culture Positive

32

Culture Negative

Study Design and Methods

2,437

THREDS

81

Met Criteria

49

Culture Positive

32

Culture Negative

1,817 no culture

Study Design and Methods

2,437

THREDS

81

Met Criteria

49

Culture Positive

32

Culture Negative

1,817 no culture 534 <50,000 WCC

Risk Factors

Demographics Health-related behaviors Clinical features Joint factors Medical comorbidities Distant site infections

Outcomes

Number of procedures performed for

septic arthritis

Number of re-admissions to the

hospital

Incidence of osteomyelitis Admission to ICU Length of stay

Outcomes

Surgical procedures > 1 Re-admission to the hospital Incidence of osteomyelitis Admission to ICU Length of stay

= Composite Outcome

Statistical Analysis

Hypothesis #1: There are prognostic factors for

culture positivity in septic arthritis patients

Hypothesis #2: There are differences in

complication rates between culture positive and culture negative septic arthritis patients

Results

Joint Culture Positive n (%) Culture Negative n (%) Knee 31 (63) 23 (72) Ankle 6 (12) 4 (13) Elbow 4 (8) 4 (13) Hip 4 (8) Shoulder 3 (6) Wrist 1 (2) 1 (3)

Results

Pathogen Frequency (%) Bacteroides non-fragilis group 1 (2) Coagulase negative Staphylococcus 1 (2) Escherichia coli 1 (2) Group B Streptococcus 3 (6) Group A Streptococcus 4 (8) Group G Streptococcus 1 (2) Klebsiella pneumoniae 1 (2) MRSA 13 (27) MSSA 18 (38) Neisseria gonorrhoeae 1 (2) Pseudomonas aeruginosa 1 (2) Streptococcus pneumoniae 3 (6)

Results

Risk Factor Culture Positive (n=49) Culture Negative (n=32) P-value Demographics Sex 0.126 Male 39 20 Female 10 12 Health Related Behaviors Alcohol 21 7 0.060 Injection Drug Use 12 2 0.039 Lab Data Synovial Fluid WCC 130181 (107894) 90689 (53055) 0.056 Positive Blood Culture 16 0.000 WBC 13.9 (6.2) 11.4 (3.8) 0.052 CRP 130.8 (66.4) 103.7 (71.0) 0.131

Significant Factors from Bivariable Analysis (P </ 0.2)

Standard deviations are provided in parenthesis

Results

Risk Factor Culture Positive (n=49) Culture Negative (n=32) P-value Local Prosthetic Joint 4 0.149 Prior Joint Surgery 12 0.002 Medical Comorbidities Diabetes Meillitus 6 10 0.047 Hepatits C 18 4 0.021 Liver Disease 6 0.076 Distant Site Infections Remote Bone Infection 6 0.076 Significant Factors from Bivariable Analysis (P >/ 0.2)

Results

Receiver Operating

Characteristic (ROC ) curve

Maximized sensitivity

and specificity

Found WBC of 13 to

be our cut-point

Results

Factor Odds Ratio P-value 95% CI Culture positivity Alcohol 6.7 0.041 1.1-42.0 Injection drug use 36.0 0.003 3.3-389.9 Serum WBC >/13 10.2 0.021 1.4-74.1

Multivariate Analysis for Culture Positivity

Results

Factor Odds Ratio P-value 95% CI Procedure Culture positivity 17.4 0.008 2.1-144.2 Osteoarthritis 0.2 0.153 0.0-1.9 Synovial WCC 1.0 0.154 0.9-1.0

Multivariate Analysis for Procedure

Results

Factor Odds Ratio P-value 95% CI Readmission Culture positivity 0.53 0.609 0.05-6.06 Antibiotics beforehand 24.71 0.020 1.66-367.35 HepC 6.44 0.059 0.93-44.33 Smoking 3.97 0.161 0.58-27.28 Alcohol 8.95 0.030 1.23-64.96

Multivariate Analysis for Readmission

Results

Factor Odds Ratio P-value 95% CI Composite Culture positivity 20.51 0.002 3.06-137.40 Age 1.05 0.053 1.00-1.11 Chills 0.17 0.041 0.03-0.93 HepC 4.50 0.049 1.00-20.16 Antibiotics beforehand 30.42 0.025 1.55-597.27

Multivariate Analysis for Composite Outcome

Summary

• IDU and alcohol users were more likely to be culture positive
• Patients with a serum WBC of 13 k/µL or greater were more likely to

be culture positive

• Culture positive patients were more likely to experience an adverse
• utcome
• Patients with culture positivity are a particular high-risk population in

whom interventions need to be focused to improve outcomes

• Patients who are IDU, alcohol users, or patients with a serum WBC of

13 k/µL or greater may be particularly prone to more severe joint sepsis and may require more aggressive treatment to mitigate adverse

• utcomes

Acknowledgements

• Dr. Saam Morshed, MD, PhD

Orthopaedic Trauma Institute Hannah Canty, MS2 Ethan Canty Steven Kwong, MS2 Monica Fernandez

• Dr. Alicia Fernandez, MD

PROF-PATH Fellowship CTR Pathway