Evidence for the benefit of hand hygiene practices in health care

1. Impact of hand hygiene on
healthcare associated infections:
Four key studies
Josh Freeman
Department of Clinical Microbiology
ADHB

2. • Before-after intervention study (Quasi-experimental)
– “Before” - 1994
– “After” - 1995-1998
• Large teaching hospital (University of Geneva Hospitals)
• Standardisation of outcome measures
– auditing of hand hygiene compliance (5 moments)
– nosocomial infections (NNISS definitions) measured by annual
prevalence surveys
– MRSA attack rate – new hospital acquired cases per 100
admissions

4. HH compliance
HH compliance improved overall from 47.6% at baseline in 1994 to 66.2% in December
1997 (p<0.001)

5. Impact on nosocomial infections and MRSA
attack rate
Between 1994 and
1998, MRSA
infections
decreased from
2.16 /10000 PD to
0.93 / 10000 PD
(p<0.001)
MRSA bacteraemia
decreased from
0.74 to 0.24 /
10000 PD (p<0.001)

6. Evidence that HH affects healthcare-associated
infections: Strengths and Weaknesses
Strengths
• Large hospital with large
sample size
• Temporal associaton
between improved hand
hygiene practice and
reduced nosocomial
infections and MRSA attack
rate
• Extended time frame post
intervention
Weaknesses
• Other interventions
targeting MRSA carried out
simultaneously
• Few data points for
nosocomial infection rates
(particularly pre-
intervention)
• “Nosocomial infections”
may be subject to
classification bias despite
standardised definitions

7. • Before-after intervention study
– Before: Jan 1999-May 2001
– After: May 2001- April 2004
• Five wards at Austin Health, Melbourne
• Intervention
– HH programme
– Mupirocin / triclosan for MRSA colonised patients on admission
• Outcomes
– Standardised HH compliance auditing (“5 moments”)
– Standardised definitions
• MRSA bacteraemia
• MRSA clinical isolates
• ESBL-E. coli and K. pneumoniae clinical isolates

8. HH compliance pre and post intervention
Overall – 21%
pre-intervention
to 42% post
intervention

9. MRSA rates pre and post intervention
Slope<0; p<0.001
Slope<0;p=0.003

10. ESBL rates pre and post intervention

11. Evidence that HH affects healthcare-associated
infections: Strengths and Weaknesses
Strengths
• Substantial and significant
association between
program onset, improved
HH compliance and
improved trends in MRSA
bacteraemia; MRSA clinical
isolates; and ESBL clinical
isolates
• Large number of data points
pre and post intervention
Weaknesses
• Intervention included
decolonisation for MRSA,
therefore difficult to
estimate relative impact of
HH on MRSA rates

12. • Before-after study (Quasi-experimental study)
– Standardised process and outcome measures
• auditing of HH compliance 4 monthly (5 moments)
• Standardised definitions of MRSA bacteraemia / clinical isolates
• Pilot study
– 6 Victorian healthcare institutions over 24 month period
• Statewide study
– 75 Victorian hospitals over 12 month period
– Rolled out in two stages: Stage 1 – March 2006-April 2007 and
stage 2 July 2006-June 2007

13. HH Compliance: Pilot program

14. MRSA bacteraemia rates: Pilot program

15. MRSA clinical isolates: Pilot program

16. HH compliance: Statewide rollout

17. MRSA bacteraemia rates: Statewide rollout

18. MRSA clinical isolates: Statewide rollout

19. Evidence that HH affects healthcare-associated
infections: Strengths and Weaknesses
Strengths
• Large, multicentre study
• Improved HH practice
temporally associated with
significant reductions in MRSA
bacteraemia in both the pilot
and statewide studies
• Large number of data points
before and after the
intervention
• MRSA bacteraemia–less
vulnerable to classification
bias than many endpoints
(“hard” endpoint)
Weaknesses
• Quasi-experimental, non-
randomised study with
historical controls– therefore
intrinsically vulnerable to
confounding
• Concurrent MRSA-specific
measures not documented
• MRSA clinical isolates started
to decrease prior to
commencing the program
(raising possibility that factors
other than the HH program
may have been driving change)

20. 24 month Outcomes from the Australian
National Hand Hygiene Initiative (MJA -in press)
• National HH initiative (Hand Hygiene Australia)
• Quasi-experimental study (2009-2010)
– “Before” - Jan 2007-Dec 2008
– “After” - Jan 2009-Dec 2010
• Nationally standardised
– Auditing of HH compliance (“5 moments”)
– MRSA bacteraemia
– Hospital-onset SA/MRSA bacteraemia

21. HH compliance by state: 2009-2010 (post intervention)
Overall 43.6% at
baseline to 67.8% post
intervention

22. National MRSA bacteraemia rates pre and post
intervention
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
Apr-07 Nov-07 Jun-08 Dec-08 Jul-09 Jan-10 Aug-10 Feb-11
RateofMRSAbacteraemiaper10,000PD's
Month
Pre NHHI
Post NHHI Implementation
Slope<0;p=0.008

23. Hospital-onset S. aureus bacteraemia rates post
intervention
0
0.2
0.4
0.6
0.8
1
1.2
1.4
RateofS.aureusbacteraemiasper10,00PD's
Month
MRSA /10,000
MSSA/10,000
SAB/10,000
Linear (MRSA /10,000)
Linear (MSSA/10,000)
Linear (SAB/10,000)

24. Evidence that HH affects healthcare-associated
infections: Strengths and Weaknesses
Strengths
• First nationwide before-after
intervention study for HH
programme with outcome
data
• Large multi centre study
• Utilises a “hard” endpoint
(MRSA bacteraemia)
• Strong temporal association
with improved compliance and
reduced MRSA bacteraemia
• Large number of data points
pre and post intervention
Weaknesses
• Vulnerable to confounding
(like all quasi-experimental
studies)
• No reduction in “hospital-
onset” S. aureus
bacteraemia or “hospital-
onset” MRSA bacteraemia

25. HH compliance infection: Association versus
causality
Bradford Hill Criterion Supports improved HH compliance as a means to reduce
infection?
Association is strong? YES – Statistically significant association between HH and infection
rates
Association is seen consistently? YES – Consistent association in four well designed studies
Cause precedes effect? YES – Improvements in hand hygiene have preceded / coincided with
reduced infections
Biological gradient (dose-
response between cause and
effect)?
YES - Inverse correlation between HH compliance rates and rates of
infection
Biologically plausible? YES – Hands of healthcare workers known to be frequently
contaminated with potential pathogens including MRSA
Coherence (compatible with
existing knowledge)?
YES- A causal relationship would be consistent with accepted models
of pathogenesis of healthcare-associated infections
Subject to experiment? NO – experimental studies not feasible / ethical
Alternate explanations for
association?
YES – Difficult to rationalise temporal association between HH
compliance and infectious endpoints based on alternative
explanations