Surveillance of nosocomial infections

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Surveillance of nosocomial infections

• Hanne Eriksen

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Nosocomial infections (NCI)

• "nosus" disease
• "komeion" to take care of
• Infections that occur during hospitalization but
  are not present nor incubating upon hospital
  admission

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Characteristics of hospitals

• Treatment is main focus
• Many stakeholders
• Shift work
• A lots of data, easily defined cohorts
• Different patient population
• Variation of length of stay
• Vulnerable patients
• Community vs. hospital

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The problem of NCI

• USA
• Urinary tract infections 2.4 per 100 admissions
• Pneumonia 1 case per 100 admissions
• Surgical site infections 2.8 per 100 operations
• NCI one death every 6th minutes
• Norway
• One of 19 patients have a NCI

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The problem of NCI

• Regional hospital, Zimbabwe
• 1 of 6 developed SSI
• 2 referral hospitals, Ethiopia
• 38.7 developed SSI
• 14 of 18 deaths attributed to SSI

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Cost of NCI

• England
• Average cost per NCI 3.000 pounds
• Extra days
• Urinary tract infections 6
• Pneumonia 12
• Surgical site infections 7

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Why surveillance?

• NCI cause of morbidity and mortality
• One third may be preventable
• Surveillance key factor
• an infection control measure
• overview of the burden and distribution of NCI
• allocate preventive resources
• Surveillance is cost-efficient!!

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The surveillance loop
Health care system
Surveillance centre
Event Action
Data Information
Reporting
Analysis, interpretation
Feedback, recommendations
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Considerations when creating a surveillance system

• Goal of the surveillance system (why)
• Engage the stakeholders (who)
• Surveillance method (what, how, when)
• definition
• what to collect
• how to collect (operation of system)
• Available resources

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• I may not have gone where I intended to go, but
  I think I have ended up
• where I needed to be
• Douglas Adams

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Objectives

• Reducing infection rates
• Establishing endemic baseline rates
• Identifying outbreaks
• Identifying risk factors
• Persuading medical personnel
• Evaluate control measures
• Satisfying regulators
• Document quality of care
• Compare hospitals NCI rates

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Who

• All hospitals?
• All departments?
• All specialties?
• Other health institutions?

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Stakeholders
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Surveillance of one or more types of NCI

• Urinary tract infections
• Lower respiratory tract infections
• Surgical site infections
• Bloodstream infections
• Conjunctivitis
• Others

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Targeted surveillance

• Special patient population
• (surgical, medical, paediatric, intensive)
• Diagnostic and therapeutic procedures
• (endoscope, haemodialysis, catheterization,
• blood transfusion)
• Specific pathogens
• (staphylococcus aureus, MRSA,
• clostridium difficile, norovirus)

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Variables

• Administrative data
• Id, address, dates of admission, discharge..
• Patient related factors
• Age, sex, severity of underlying disease
• Procedures
• Surgery
• Devices (e.g. catheters)
• Treatment, diagnosis
• Use of antibiotics

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Stratification points, surgical site infections
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When?

• During hospital stay?
• Frequency of data collection
• After discharge?
• When and how?

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How?

• Two main surveillance methods
• incidence
• prevalence
• Variations within these methods

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 Incidence (cohort) studies marching towards
outcomes
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Cohort design
Prospective
NCI
Exposed
T
Study group
PAR
Not exposed
T
PAR Population at Risk T Time period
Retrospective
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Measure

• Percentage
• NCI / patients
• Incidence density
• Patient-days as denominator
• Risk factors
• RR risk in patients exposed
• risk in patients not exposed

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Positive aspects

• Provide information on several risk factors
• Exposure measures before outcome
• Information on consequences of NCI
• Can identify outbreak
• Ongoing attention

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Limitations

• Resource demanding
• Loss of follow-up
• Seldom NCI
• Confounding and bias is possible

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Prevalence

• Measures number of current NCI
• Within a defined population at risk
• At a given time
• NCI / patients at risk 100
• Point or period prevalence

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Use of prevalence surveys

• Show trends
• Estimate
• distribution of NCI
• surveillance accuracy
• incidence from prevalence??
• antimicrobial usage patterns
• Rise awareness

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Limitations

• Do not identify causes
• Duration of NCI affects the prevalence
• Not very suitable for small institutions
• Difficult to adjust prevalence

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Prevalence survey
UTI n6 SSI n2
Incidence surveillance
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Define method

• Identify and review
• Protocols used elsewhere e.g.
• HELICS incidence, Norway's prevalence
• Literature
• Minimum dataset

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Methodological issues

• Definitions
• NCI
• Cut off 48 or 72 hours?
• Criterias from Centers for Disease Control and
  Prevention (hospital)
• McGeer (long-term care facilities)
• Risk variables
• Case finding
• Active or passive
• By whom?
• After discharge?
• Prospective or retrospective?

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Case finding

• Active by surveillance personnel
• Passive by medical personnel
• Laboratory or clinical based
• Source of data
• Clinical examinations
• Medical records, reports from laboratories
• Forms or interviews

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Ongoing systematic collection?

• Cohort
• Continual?
• Periodical?
• Prevalence
• Weekly?
• Yearly?
• Depends on objectives

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Precision of estimate
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Dummy table
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Implementing surveillance system

• Administrators responsibility
• Involvement of stakeholders
• Identify available resources
• Personnel
• Money
• Time
• Equipment
• It- solutions
• Realistic project plan
• Organization map
• Making forms and letters
• It-solutions
• Training
• Use of data

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Making surveillance work

• Support by the administrators
• Involve local experts
• Simple
• Minimize resources required by hospitals
• Training
• Feedback and use of data
• Flexibility

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Training topics

• Why surveillance?
• How?
• Definition
• Case finding
• Case studies
• It-solution
• Use of data

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Quality controls

• Define acceptable loss of follow-up
• Make sure all patients are included
• Identify infections
• Use several sources
• Compare data, conduct surveys
• Training
• Clean data
• Completeness
• Logical values

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Use of data

• Prevent NCI
• Ward audits
• Present data to hospitals, administrators, MoH,
  patients
• Argument for resource allocation
• Audits for medical personnel
• Raise awareness

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Incidence of SSI over time
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Conclusion
Pathogen
Unhappy patients
Unhappy director
Hospital
Surveillance
Happy Patients
Happy director
Hospital