variations in the frequency of mrsa infections across acute nhs hospitals, 2001-2006 paul fenn dev...
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Variations in the frequency of MRSA infections across acute NHS hospitals, 2001-2006
Paul FennDev VencappaAlastair GrayOliver RiveroNeil Rickman
Background This study originated as part of research on the relationship
between liability risk-sharing measures and patient safety in the NHS [funded under the ESRC Public Services Programme]
Data on risk sharing measures available from the NHS Litigation Authority
Discounts available for risk management standards; hypothesis – financial incentives improve (or signal) patient safety measures, including hospital hygeine
MRSA surveillance data collected by Health Protection Agency since 2001 has progressively extended the panel of data that can be analysed alongside other DoH administrative datasets
Permits a wider set of hypotheses to be tested using panel data estimation methods in relation to the factors driving MRSA infection rates across hospitals and over time
Changes in length of stay, casemix and bed utilisation could plausibly affect the rate of hospital infections
Trends
Staphylococcus aureus bacteraemia reports (HPA, 2007)
MRSA bacteraemia reports from 2001 to 2006
01
23
45
67
89
10R
ate
per
10,0
00 F
CE
s
020
0040
0060
0080
00T
otal
MR
SA
rep
orts
2001 2002 2003 2004 2005 2006Year
Total MRSA reports Rate per 10,000 FCEs
MRSA infection rates by HC region from 2001 to 2006
46
810
46
810
46
810
2000 2002 2004 20062000 2002 2004 20062000 2002 2004 2006
East Midlands East of England London
North East North West South Central
South East South West West Midlands
MR
SA
infe
ctio
ns p
er 1
0,00
0 F
CE
s
YearGraphs by geo_local
Mean length of stay by HC region from 2001 to 2006
2.5
33.
54
2.5
33.
54
2.5
33.
54
2000 2002 2004 20062000 2002 2004 20062000 2002 2004 2006
East Midlands East of England London
North East North West South Central
South East South West West MidlandsMea
n le
ngth
of
stay
YearGraphs by geo_local
Mean bed utilisation rates by HC region from 2001 to 2006
.8.8
5.9
.8.8
5.9
.8.8
5.9
2000 2002 2004 20062000 2002 2004 20062000 2002 2004 2006
East Midlands East of England London
North East North West South Central
South East South West West Midlands
Mea
n be
d ut
ilisa
tion
rate
YearGraphs by geo_local
Distributions
Distributions of MRSA infections, NHS Acute Trusts
2001 2002 2003 2004 2005 2006 Total Nos.
0 3 3 2 4 4 3 19 1-10 21 17 22 20 19 18 117
11-20 24 29 19 23 20 30 145 21-30 29 23 32 31 33 35 183 31-40 29 33 24 18 25 22 151 41-50 13 15 14 18 13 16 89 51-60 9 10 15 13 16 14 77 61-70 6 5 8 11 10 11 51 71-80 7 9 2 6 8 7 39 81-90 5 5 7 6 2 4 29
91-100 9 5 6 7 7 4 38 101-110 2 5 6 5 5 4 27 111-120 2 2 1 1 3 1 10 121-130 2 2 4 3 0 0 11 131-140 0 0 3 0 1 0 4 141-150 2 2 0 0 1 0 5 151-160 1 1 0 1 0 0 3 161-170 1 2 1 0 1 0 5 171-180 0 0 0 0 0 1 1 181-190 1 1 1 0 0 0 3 191-200 1 0 0 1 0 0 2 201-210 0 0 1 0 0 0 1
Total 167 169 168 168 168 170 1,010 Source: MRSA Surveillance System, Department of Health
Distributions of MRSA infection rates by HC region
010
2030
010
2030
010
2030
0 10 20 30 0 10 20 30 0 10 20 30
East Midlands East of England London
North East North West South Central
South East South West West Midlands
Per
cent
MRSA infection rates/10,000 FCEsGraphs by geo_local
Drivers
Activity levels and casemix 2001-2006
2001 2002 2003 2004 2005 2006 Total
Finished consultant episodes 65098 70261 74359 76596 80573 83632 75246
Mean length of stay (days) 3.585 3.491 3.453 3.263 2.995 2.790 3.258
Bed utilisation rate 0.837 0.844 0.847 0.843 0.840 0.836 0.841
Proportion general medicine 0.219 0.238 0.252 0.248 0.247 0.235 0.240
Proportion general surgery 0.097 0.103 0.105 0.104 0.104 0.102 0.103
Proportion gynaecology 0.033 0.035 0.035 0.033 0.033 0.034 0.034
Proportion obstetrics 0.035 0.036 0.038 0.038 0.038 0.038 0.037
Proportion paediatrics 0.068 0.070 0.071 0.068 0.074 0.074 0.071
Proportion trauma/ orthopaedics 0.106 0.114 0.116 0.115 0.113 0.114 0.113
Proportion urology 0.020 0.022 0.022 0.022 0.021 0.021 0.021
Proportion other surgery 0.062 0.065 0.066 0.066 0.064 0.065 0.065
Proportion other medicine 0.257 0.282 0.280 0.290 0.289 0.304 0.284
Source: Hospital Episode Statistics by specialty, Department of Health
Direct measures to control MRSA, 2003-2007 2003: CMO provides specific directions on actions that
should be taken to reduce healthcare associated infections: better surveillance, improved techniques for use of catheters, tubes and
instruments, higher standards of hygiene in clinical practice, more prudent use of antibiotics, and a range of managerial and organisational changes
2004: “CleanYourHands” campaign launched by the NPSA 2004: DoH directs additional resources towards NHS trusts
with particularly high MRSA rates 2006: new Health Act introduced
detailed hygiene code for NHS organisations to assess and manage infection risks, implement clinical care protocols, and provide training
2007: “Deep Clean” initiative launched by DoH
CNST risk management standards, 2001-2006
Year Risk management standards Total 0 1 2 3 2001 20 117 26 1 164 2002 21 111 29 3 164 2003 7 115 39 5 166 2004 0 110 46 10 166 2005 0 88 68 10 166 2006 0 88 70 10 168
Total 48 629 278 39 982
CNST discount: 0% 10% 20% 30%
Source: NHS Litigation Authority
Standard 1 2 3 4 5
Criterion Governance
Competent &Capable
Workforce
SafeEnvironment
ClinicalCare
Learning fromExperience
1 Risk management strategy
Corporate induction Secure environment Patient identification Incident reporting
2 Policy on procedural documents
Local induction of permanent staff
Child protection Patient information Raising concerns
3 Risk management committee(s)
Local induction of temporary staff
Vulnerable adults Consent Complaints
4 Risk awareness training for senior management
Supervision of medical staff
in training
Moving & handling Clinical record-keeping standards
Claims
5 Risk management process
Risk management training
Slips, trips & falls Transfer of patients Investigations
6 Risk register Training needs analysis Inoculation incidents Medicines management
Analysis
7 Responding to external recommendations specific to the organisation
Medical devices training
Maintenance of medical devices & equipment
Blood transfusion Improvement
8 Clinical records management
Hand hygiene training Harassment & bullying Resuscitation Best practice - NICE, NCEs & national guidance
9 Professional clinical registration
Moving & handling training
Violence & aggression Infection control Best practice - NSFs & high level enquiries
10 Employment checks Supporting staff involved in an incident, complaint or claim
Stress Discharge of patients Being open
Source: NHSLA April 2007
Estimation
Estimating equation
= number of reported MRSA infections, hospital i, year titx
2ln( )itit it i it
it
xd u v
T 1βρ
= number of finished consultant episodes, hospital i, year titT
= vector of activity and casemix variables, hospital i, year titρ
= error term, hospital i, year titv
= vector of CNST risk management standards, hospital i, year titd
= unobserved effect, hospital iiu
Estimation Issues
Zero observations [xit = 0] Some hospitals omitted from analysis Solution: assume count data process
and estimate using QMLE or MLE
2ln( )itit it i it
it
xd u v
T 1βρ
Estimation Issues
Clustered sampling [it is not iid in pooled regression] Can lead to over-acceptance of
hypotheses relating to β1 and β2 Solution: use cluster-robust standard
errors
2ln( )itit it i it
it
xd u v
T 1βρ
Estimation Issues
Unobserved heterogeneity [ui ≠ 0] Omitted variable bias and/or inefficiency
if hospital effects unmodelled Solution: use panel data estimation
methods (random effects; fixed effects; first differencing)
2ln( )itit it i it
it
xd u v
T 1βρ
Estimation Issues
Endogeneity [E(ditvit) ≠ 0] Simultaneity bias Solution: use IV or GMM estimation
methods Internal instruments: lagged values of dit External instruments: claims experience of
hospital
2ln( )itit it i it
it
xd u v
T 1βρ
Results
(1) (2) (3) (4) (5) (6) Pooled
OLS RE GLS
FE OLS
Poisson QMLE
RE NB-ML
FE NB-ML
Ln(length of stay) 0.652*** 0.610*** 0.500** 0.884*** 0.769*** 0.476* (4.43) (5.29) (3.15) (5.52) (5.31) (2.20) Ln(bed utilization rate) -0.222 -0.122 -0.0754 -0.122 -0.0247 -0.0419 (-0.53) (-0.48) (-0.26) (-0.31) (-0.07) (-0.11) CNST level2 -0.0401 -0.0310 -0.0157 -0.0406 -0.0217 -0.0233 (-0.86) (-0.94) (-0.42) (-0.95) (-0.67) (-0.46) CNST level3 -0.206* -0.137 -0.0816 -0.160 -0.114 -0.00986 (-2.10) (-1.68) (-0.87) (-1.66) (-1.59) (-0.06) Proportion general surgery 0.233 0.926 3.196* 1.431 1.706 3.929* (0.18) (0.98) (2.18) (1.46) (1.88) (2.03) Proportion gynaecology -1.002 -1.193 -3.313* -1.658 -1.387 -2.223 (-1.34) (-1.70) (-2.10) (-1.77) (-1.93) (-1.00) Proportion obstetrics -1.088* -1.673** -3.938** -1.617* -2.488** -3.940* (-1.99) (-3.10) (-2.90) (-2.00) (-3.15) (-2.15) Proportion paediatrics -0.637 -0.696 -0.897 -0.582 -0.475 0.269 (-1.38) (-1.75) (-1.14) (-0.99) (-1.03) (0.17) Proportion trauma & orthopaedics -0.474 -0.575 0.896 -0.461 -0.707* 1.209 (-1.43) (-1.83) (0.70) (-1.23) (-2.23) (0.66) Proportion urology -0.904 -1.431 -1.325 -0.403 -1.244 -0.810 (-0.35) (-0.67) (-0.38) (-0.18) (-0.64) (-0.18) Proportion other surgery 1.375** 1.150*** 0.384 1.364*** 0.835* 0.187 (3.29) (3.56) (0.73) (3.34) (2.38) (0.27) Proportion other medicine 0.215 0.126 -0.0957 0.111 0.0863 -0.126 (0.98) (0.75) (-0.40) (0.56) (0.53) (-0.38) Proportion psychiatry -1.338 -1.603** -1.295* -1.319 -1.698** -0.969 (-1.85) (-2.84) (-2.00) (-1.92) (-3.11) (-1.08) Single specialty hospital -0.946*** -0.829*** -0.915*** -0.763*** (-4.37) (-5.84) (-4.73) (-4.32) Teaching hospital 0.205** 0.191** 0.211*** 0.212*** (3.05) (2.88) (3.40) (3.51)
Estimation with exogenous regressors
Note: Region and year dummies omitted
(1) (2) (3) (4) (5) (6) Pooled
OLS RE GLS
FE OLS
Poisson QMLE
RE NB-ML
FE NB-ML
Ln(length of stay) 0.652*** 0.610*** 0.500** 0.884*** 0.769*** 0.476* (4.43) (5.29) (3.15) (5.52) (5.31) (2.20) Ln(bed utilization rate) -0.222 -0.122 -0.0754 -0.122 -0.0247 -0.0419 (-0.53) (-0.48) (-0.26) (-0.31) (-0.07) (-0.11) CNST level2 -0.0401 -0.0310 -0.0157 -0.0406 -0.0217 -0.0233 (-0.86) (-0.94) (-0.42) (-0.95) (-0.67) (-0.46) CNST level3 -0.206* -0.137 -0.0816 -0.160 -0.114 -0.00986 (-2.10) (-1.68) (-0.87) (-1.66) (-1.59) (-0.06) Proportion general surgery 0.233 0.926 3.196* 1.431 1.706 3.929* (0.18) (0.98) (2.18) (1.46) (1.88) (2.03) Proportion gynaecology -1.002 -1.193 -3.313* -1.658 -1.387 -2.223 (-1.34) (-1.70) (-2.10) (-1.77) (-1.93) (-1.00) Proportion obstetrics -1.088* -1.673** -3.938** -1.617* -2.488** -3.940* (-1.99) (-3.10) (-2.90) (-2.00) (-3.15) (-2.15) Proportion paediatrics -0.637 -0.696 -0.897 -0.582 -0.475 0.269 (-1.38) (-1.75) (-1.14) (-0.99) (-1.03) (0.17) Proportion trauma & orthopaedics -0.474 -0.575 0.896 -0.461 -0.707* 1.209 (-1.43) (-1.83) (0.70) (-1.23) (-2.23) (0.66) Proportion urology -0.904 -1.431 -1.325 -0.403 -1.244 -0.810 (-0.35) (-0.67) (-0.38) (-0.18) (-0.64) (-0.18) Proportion other surgery 1.375** 1.150*** 0.384 1.364*** 0.835* 0.187 (3.29) (3.56) (0.73) (3.34) (2.38) (0.27) Proportion other medicine 0.215 0.126 -0.0957 0.111 0.0863 -0.126 (0.98) (0.75) (-0.40) (0.56) (0.53) (-0.38) Proportion psychiatry -1.338 -1.603** -1.295* -1.319 -1.698** -0.969 (-1.85) (-2.84) (-2.00) (-1.92) (-3.11) (-1.08) Single specialty hospital -0.946*** -0.829*** -0.915*** -0.763*** (-4.37) (-5.84) (-4.73) (-4.32) Teaching hospital 0.205** 0.191** 0.211*** 0.212*** (3.05) (2.88) (3.40) (3.51)
Estimation with exogenous regressors
Note: Region and year dummies omitted
(1) (2) (3) (4) (5) (6) Pooled
OLS RE GLS
FE OLS
Poisson QMLE
RE NB-ML
FE NB-ML
Ln(length of stay) 0.652*** 0.610*** 0.500** 0.884*** 0.769*** 0.476* (4.43) (5.29) (3.15) (5.52) (5.31) (2.20) Ln(bed utilization rate) -0.222 -0.122 -0.0754 -0.122 -0.0247 -0.0419 (-0.53) (-0.48) (-0.26) (-0.31) (-0.07) (-0.11) CNST level2 -0.0401 -0.0310 -0.0157 -0.0406 -0.0217 -0.0233 (-0.86) (-0.94) (-0.42) (-0.95) (-0.67) (-0.46) CNST level3 -0.206* -0.137 -0.0816 -0.160 -0.114 -0.00986 (-2.10) (-1.68) (-0.87) (-1.66) (-1.59) (-0.06) Proportion general surgery 0.233 0.926 3.196* 1.431 1.706 3.929* (0.18) (0.98) (2.18) (1.46) (1.88) (2.03) Proportion gynaecology -1.002 -1.193 -3.313* -1.658 -1.387 -2.223 (-1.34) (-1.70) (-2.10) (-1.77) (-1.93) (-1.00) Proportion obstetrics -1.088* -1.673** -3.938** -1.617* -2.488** -3.940* (-1.99) (-3.10) (-2.90) (-2.00) (-3.15) (-2.15) Proportion paediatrics -0.637 -0.696 -0.897 -0.582 -0.475 0.269 (-1.38) (-1.75) (-1.14) (-0.99) (-1.03) (0.17) Proportion trauma & orthopaedics -0.474 -0.575 0.896 -0.461 -0.707* 1.209 (-1.43) (-1.83) (0.70) (-1.23) (-2.23) (0.66) Proportion urology -0.904 -1.431 -1.325 -0.403 -1.244 -0.810 (-0.35) (-0.67) (-0.38) (-0.18) (-0.64) (-0.18) Proportion other surgery 1.375** 1.150*** 0.384 1.364*** 0.835* 0.187 (3.29) (3.56) (0.73) (3.34) (2.38) (0.27) Proportion other medicine 0.215 0.126 -0.0957 0.111 0.0863 -0.126 (0.98) (0.75) (-0.40) (0.56) (0.53) (-0.38) Proportion psychiatry -1.338 -1.603** -1.295* -1.319 -1.698** -0.969 (-1.85) (-2.84) (-2.00) (-1.92) (-3.11) (-1.08) Single specialty hospital -0.946*** -0.829*** -0.915*** -0.763*** (-4.37) (-5.84) (-4.73) (-4.32) Teaching hospital 0.205** 0.191** 0.211*** 0.212*** (3.05) (2.88) (3.40) (3.51)
Estimation with exogenous regressors
Note: Region and year dummies omitted
(1) (2) (3) (4) (5) (6) Pooled
OLS RE GLS
FE OLS
Poisson QMLE
RE NB-ML
FE NB-ML
Ln(length of stay) 0.652*** 0.610*** 0.500** 0.884*** 0.769*** 0.476* (4.43) (5.29) (3.15) (5.52) (5.31) (2.20) Ln(bed utilization rate) -0.222 -0.122 -0.0754 -0.122 -0.0247 -0.0419 (-0.53) (-0.48) (-0.26) (-0.31) (-0.07) (-0.11) CNST level2 -0.0401 -0.0310 -0.0157 -0.0406 -0.0217 -0.0233 (-0.86) (-0.94) (-0.42) (-0.95) (-0.67) (-0.46) CNST level3 -0.206* -0.137 -0.0816 -0.160 -0.114 -0.00986 (-2.10) (-1.68) (-0.87) (-1.66) (-1.59) (-0.06) Proportion general surgery 0.233 0.926 3.196* 1.431 1.706 3.929* (0.18) (0.98) (2.18) (1.46) (1.88) (2.03) Proportion gynaecology -1.002 -1.193 -3.313* -1.658 -1.387 -2.223 (-1.34) (-1.70) (-2.10) (-1.77) (-1.93) (-1.00) Proportion obstetrics -1.088* -1.673** -3.938** -1.617* -2.488** -3.940* (-1.99) (-3.10) (-2.90) (-2.00) (-3.15) (-2.15) Proportion paediatrics -0.637 -0.696 -0.897 -0.582 -0.475 0.269 (-1.38) (-1.75) (-1.14) (-0.99) (-1.03) (0.17) Proportion trauma & orthopaedics -0.474 -0.575 0.896 -0.461 -0.707* 1.209 (-1.43) (-1.83) (0.70) (-1.23) (-2.23) (0.66) Proportion urology -0.904 -1.431 -1.325 -0.403 -1.244 -0.810 (-0.35) (-0.67) (-0.38) (-0.18) (-0.64) (-0.18) Proportion other surgery 1.375** 1.150*** 0.384 1.364*** 0.835* 0.187 (3.29) (3.56) (0.73) (3.34) (2.38) (0.27) Proportion other medicine 0.215 0.126 -0.0957 0.111 0.0863 -0.126 (0.98) (0.75) (-0.40) (0.56) (0.53) (-0.38) Proportion psychiatry -1.338 -1.603** -1.295* -1.319 -1.698** -0.969 (-1.85) (-2.84) (-2.00) (-1.92) (-3.11) (-1.08) Single specialty hospital -0.946*** -0.829*** -0.915*** -0.763*** (-4.37) (-5.84) (-4.73) (-4.32) Teaching hospital 0.205** 0.191** 0.211*** 0.212*** (3.05) (2.88) (3.40) (3.51)
Estimation with exogenous regressors
Note: Region and year dummies omitted
(1) (2) (3) (4) (5) (6) Pooled
OLS RE GLS
FE OLS
Poisson QMLE
RE NB-ML
FE NB-ML
Ln(length of stay) 0.652*** 0.610*** 0.500** 0.884*** 0.769*** 0.476* (4.43) (5.29) (3.15) (5.52) (5.31) (2.20) Ln(bed utilization rate) -0.222 -0.122 -0.0754 -0.122 -0.0247 -0.0419 (-0.53) (-0.48) (-0.26) (-0.31) (-0.07) (-0.11) CNST level2 -0.0401 -0.0310 -0.0157 -0.0406 -0.0217 -0.0233 (-0.86) (-0.94) (-0.42) (-0.95) (-0.67) (-0.46) CNST level3 -0.206* -0.137 -0.0816 -0.160 -0.114 -0.00986 (-2.10) (-1.68) (-0.87) (-1.66) (-1.59) (-0.06) Proportion general surgery 0.233 0.926 3.196* 1.431 1.706 3.929* (0.18) (0.98) (2.18) (1.46) (1.88) (2.03) Proportion gynaecology -1.002 -1.193 -3.313* -1.658 -1.387 -2.223 (-1.34) (-1.70) (-2.10) (-1.77) (-1.93) (-1.00) Proportion obstetrics -1.088* -1.673** -3.938** -1.617* -2.488** -3.940* (-1.99) (-3.10) (-2.90) (-2.00) (-3.15) (-2.15) Proportion paediatrics -0.637 -0.696 -0.897 -0.582 -0.475 0.269 (-1.38) (-1.75) (-1.14) (-0.99) (-1.03) (0.17) Proportion trauma & orthopaedics -0.474 -0.575 0.896 -0.461 -0.707* 1.209 (-1.43) (-1.83) (0.70) (-1.23) (-2.23) (0.66) Proportion urology -0.904 -1.431 -1.325 -0.403 -1.244 -0.810 (-0.35) (-0.67) (-0.38) (-0.18) (-0.64) (-0.18) Proportion other surgery 1.375** 1.150*** 0.384 1.364*** 0.835* 0.187 (3.29) (3.56) (0.73) (3.34) (2.38) (0.27) Proportion other medicine 0.215 0.126 -0.0957 0.111 0.0863 -0.126 (0.98) (0.75) (-0.40) (0.56) (0.53) (-0.38) Proportion psychiatry -1.338 -1.603** -1.295* -1.319 -1.698** -0.969 (-1.85) (-2.84) (-2.00) (-1.92) (-3.11) (-1.08) Single specialty hospital -0.946*** -0.829*** -0.915*** -0.763*** (-4.37) (-5.84) (-4.73) (-4.32) Teaching hospital 0.205** 0.191** 0.211*** 0.212*** (3.05) (2.88) (3.40) (3.51)
Estimation with exogenous regressors
Note: Region and year dummies omitted
(1) (2) (3) (4) (5) Pooled
linear GMM
RE EC2SLS
FE linear GMM
Pooled nonlinear GMM
q-diff nonlinear GMM
Ln(length of stay) 0.653*** 0.620*** 0.506** 0.862*** 0.836*** (4.60) (5.41) (3.14) (5.52) (3.62) Ln(bed utilization rate) -0.212 -0.125 -0.0915 -0.118 0.5293 (-0.53) (-0.49) (-0.31) (-0.31) (1.20) CNST level2 -0.0114 -0.108 -0.107 -0.051 (-0.12) (-1.54) (-0.54) (-0.57) CNST level3 -0.290** -0.224 -0.212 -0.328*** -0.0523 (-3.17) (-1.49) (-0.41) (-4.21) (-0.81) Proportion general surgery -0.103 0.808 3.089* 1.211 -2.5777 (-0.08) (0.86) (2.08) (1.30) (-1.28) Proportion gynaecology -0.829 -0.984 -3.157 -1.661 -2.8448 (-1.16) (-1.39) (-1.86) (-1.80) (-1.32) Proportion obstetrics -1.206* -1.569** -4.013** -2.009* -3.166* (-2.31) (-2.91) (-2.92) (-2.51) (-1.99) Proportion paediatrics -0.692 -0.689 -0.826 -0.698 -1.0807 (-1.54) (-1.76) (-0.97) (-1.24) (-1.08) Proportion trauma & orthopaedics -0.569 -0.544 1.153 -0.689* -0.6474 (-1.73) (-1.76) (0.87) (-2.00) (-0.68) Proportion urology -0.884 -0.915 -0.594 0.416 -12.387 (-0.35) (-0.43) (-0.16) (0.20) (-1.89) Proportion other surgery 1.215** 1.169*** 0.460 1.001** 0.0501 (3.05) (3.68) (0.82) (2.67) (0.05) Proportion other medicine 0.172 0.151 -0.0539 -0.019 -0.3767 (0.86) (0.90) (-0.21) (-0.10) (-1.19) Proportion psychiatry -1.415 -1.635** -1.305* -1.381* -4.096** (-1.95) (-2.87) (-2.00) (-2.00) (-3.60) Single specialty hospital -0.928*** -0.831*** -0.801*** (-4.40) (-5.97) (-4.62) Teaching hospital 0.228*** 0.194** 0.235*** (3.49) (3.01) (4.06)
Estimation with endogenous regressors
Note: Region and year dummies omitted
Unexplained reduction in MRSA rate relative to 2001
-20.00%
-15.00%
-10.00%
-5.00%
0.00%
5.00%
2001 2002 2003 2004 2005 2006
Pooled OLS
RE GLS
FE OLS
Poisson QMLE
RE NB-ML
FE NB-ML
Pooled GMM
RE EC2SLS
FE GMM
Nonlinear GMM
Conclusions
Conclusions Average length of stay is the main driver behind changes in
MRSA infection rates over time Of the 27% fall in MRSA rates between 2001/2 and 2006/7,
somewhere between 11% (short-run) and 19% (long-run) is attributable to the overall fall in length of stay over this period
Because the other factors we explored are either insignificant or have changed little over the period, the remaining fall in the MRSA rate is “unexplained” and could potentially be attributable to measures such as the NPSA’s “CleanYourHands” campaign
Casemix and location are important factors explaining differences in MRSA rates across acute hospitals
Hospitals with a higher proportion of surgical admissions have higher MRSA rates; hospitals with a higher proportion of O&G, paediatric, and psychiatric admissions have lower MRSA rates.
Acute hospitals in London, the South-East and the West Midlands have significantly higher MRSA rates than in other regions, after controlling for other factors including casemix and length of stay
Conclusions Controlling for casemix, location and length of stay,
single-specialty acute hospitals have much lower MRSA rates than other acute hospitals
Controlling for casemix, location and length of stay, acute teaching hospitals have higher MRSA rates than other acute hospitals (although this differential has weakened considerably since 2003)
There is some (inconclusive) evidence that hospitals achieving the highest CNST risk management standard (level 3) have lower MRSA infection rates
There is no evidence that, after controlling for location, variations in bed utilisation rates across acute hospitals have a significant effect on their MRSA infection rates