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Journal Watch
Healthcare Infection 2008; 13: 21–23
Journal Watch Journal Watch presents a breif description of articles recently published in other journals and thought to be of relevance or interest to the AIC readership. Readers are encouraged to refer to the full article for complete information.
Elements of influenza vaccination programs that predict higher vaccination rates: results of an emerging infections network survey Following the Healthcare Infection Control Practices Advisory Committee (HICPAC) and the Advisory Committee on Immunization Practices (ACIP) release of recommendations designed to increase vaccination rates among health care workers (HCWs), 991 infectious diseases consultants were surveyed by the Infectious Diseases Society of America regarding vaccination programs at their respective institutions. The recommendations were formulated as a result of continuing low vaccination rates, and were evidence based. They include several specific measures aimed at encouraging vaccination, including education regarding the benefits of influenza vaccination, providing free vaccination and easy access, obtaining a signed declination form from HCWs who refuse vaccination and using the level of vaccination coverage as a measure of patient safety and quality of care. One aim of the survey was to examine the level of implementation of the recommendations. There were 418 valid responses to the survey. Vaccination rates for all health care workers in most institutions were between 41 and 60%. Logistic regression models were used to determine predictors of vaccination rates – and all program elements were significant predictors of vaccination rates in univariate analysis. Because the elements were highly associated with each other, another statistical method (principal components analysis) was used to find combinations of the elements that would serve as optimal predictors of higher vaccination rates. The results of the survey indicated that many hospitals have not completely implemented the HICPAC/ACIP recommendations. Almost all institutions provided vaccine free of charge to HCWs, and most (87%) offered the vaccine in locations convenient to HCWs; however, few offered vaccine at staff meetings or out of hours clinics. The two least implemented recommendations were requiring signed declination statements and practicing active surveillance for healthcare acquired influenza. Nine institutions reported that signed declinations would be required for the next season (2006/2007). Twenty one percent of respondents did not know their vaccination rates and 5% reported that rates could not be determined. Most (62%) vaccinated 60% of HCWs and only 10% reported rates 80%. Rates were significantly higher in institutions that required signed declination statements.
Australian Infection Control Association 2008
The principal components analysis suggested that the most effective elements for a successful vaccination campaign are: vaccine free of charge, devoting adequate resources to vaccination efforts and education of targeted groups of HCWs. The authors report being disappointed at the general low level of implementation of the recommendations and also that infectious diseases consultants generally support public reporting of institution vaccination rates. Polgreen PM, Chen Y, Beekmann S, Srinivasan A, Neill MA, Gay T, Cavanaugh JE. Elements of influenza vaccination programs that predict higher vaccination rates: results of an emerging infections network survey. Clin Inf Dis 2008; 46: 14–19.
Risk factors and recommendations for rate stratification for surveillance of neonatal healthcare-associated bloodstream infection The aim of this study was to assess key potential risk factors for bloodstream infection (BSI) in neonates and to determine those most appropriate for stratifying BSI rates and to enable valid comparisons between hospitals with differing case-mixes. The authors argue that due to the variation in case-mix between neonatal units, risk stratification should relate risks to neonates rather than to the unit as a whole, whereas the latter method is currently the method used by the English Nosocomial Infection National Surveillance Scheme. All 1367 babies admitted to the neonatal unit at a London Hospital over a 34-month period were followed from admission to discharge for development of BSI. The definitions for development of BSI used differ from National Healthcare Safety Network (NHSN) definitions. Data recorded included gender, gestational age, birthweight, postnatal age (recorded daily), endotracheal tube, nasal cunnulae, central vascular device, peripheral vascular device, parenteral nutrition, nasogastric tube and ‘receiving breast milk’. The relationship between BSI and birthweight, gestational age and postnatal age was considered unlikely to be linear so statistical techniques were used to fit a curve for each of these variables – each showed an initial curved relationship indicating a higher risk for lower birthweight, gestational age and postnatal age which then plateaued. For this reason these variables were modelled as categorical variables with three categories – high, medium, and falling to low risk as the curve levelled off.
DOI: 10.1071/HI08005
21
Healthcare Infection
Univariate Poisson regressions indicated that all risk factors except gender and exposure to breast milk in the previous 3 days were significantly associated with BSI, with the strongest associations being parenteral nutrition, birthweight <700 g, gestational age <26 weeks and central vascular device. Subsequent multiple regression analysis identified only parenteral nutrition within the preceding 3 days and gestational age <26 weeks as significant independent risk factors. The BSI rate was 40 times higher in infants with these two risk factors than in infants without these risk factors. Parenteral nutrition has now been recognised as a risk factor in several studies, and the authors argue that it could be a mistake that many surveillance programs for neonates focus primarily on the risks of intravascular catheters without considering the nature of the associated infusate. They suggest that given that at least in the UK, use of parenteral nutrition varies widely between institutions, any inter-hospital comparisons that do not take account of this as a risk factor would be invalid. The authors also recommend stratifying by gestational age but recognise that birthweight is easier to capture and might be a viable alternative. They acknowledge weaknesses in their study including the fact that it was single site and also the need for validation of their findings. Holmes A, Dore´ CJ, Saraswatula A, Bamford KB, Richards MS, Coello R, Modi N. Risk factors and recommendations for rate stratification for surveillance of neonatal healthcare-associated bloodstream infection. J Hosp Inf 2008; 68: 66–72.
Ventilator-associated pneumonia as a quality indicator for patient safety? This article discusses ventilator-associated pneumonia (VAP) and the concept of benchmarking in health care, particularly in relation to VAP. The authors argue against considering VAP rates as a potential candidate for benchmarking or for monitoring quality of patient care on the basis that at the present time, accurate benchmarking is not feasible. Reasons given for this argument include the difficulty with case definition and diagnosis and assessment of severity of pneumonia, the complexity of surveillance for VAP due to the need to access multiple data sources and case-mix complexities particularly in relation to critically ill patients. Alternatively it is suggested that some risk factors are modifiable and can be monitored and used as quality indicators. The main risk factors are listed in the article together with a measure of the strength of the evidence for each risk factor. Process improvements have been shown to reduce VAP rates, usually in studies where they have been implemented as ‘bundles’. Overall, they conclude that benchmarking VAP rates is hazardous and potentially misleading but that use of evidence-based process indicators as part of a well 22
defined surveillance system can serve as quality indicators and ultimately improve patient safety and quality of care. U¸c kay I, Ahmed QA, Sax H, Pittet D. Ventilator-associated pneumonia as a quality indicator for patient safety? Clin Inf Dis 2008; 46: 557–563.
Nasal carriage of S. aureus increases the risk of surgical site infection after major heart surgery This article describes a 1-year observational study during which patients undergoing major heart surgery (MHS) were screened for nasal carriage of Staphylococcus aureus before surgery. The authors contend that data on risks of surgical site infection (SSI) in nasal carriers is scarce but suggest that it may be a risk factor following cardiac surgery and they note that there are no commonly recognised guidelines that specifically recommend screening and decolonisation. The study aimed to determine the incidence of carriers in the population undergoing MHS at a 1750-bed tertiary referral teaching hospital in Spain and to assess the impact of nasal carriage on the incidence of SSI in these patients. Cases of SSI were recorded and risk factors of patients with and without SSI were analysed. There were a total of 357 patients include in the study of which 96 (27%) were found to be nasal carriers of S. aureus and nine of these had methicillin resistant strains (MRSA). Infections were diagnosed according to CDC criteria and superficial and deep incisional SSIs were included. Patients were not decolonised and vancomycin prophylaxis was not provided; however, contact precautions were taken with patients known to be MRSA carriers. Renal failure was found to be the only condition associated with increased risk (RR 2.3, 95% CI: 1.35–3.95) for nasal carriage of S. aureus. Risk factors associated with nasal carriage of MRSA were obesity (RR 5.07, 95% CI 1.29–20.0) and previous cerebrovascular accident (RR 4.99, 95% CI 1.2–18.8). Twenty three patients developed an SSI (6.4%). Fifteen (4.2%) had postsurgical mediastinitis and eight (2.2%) had a superficial SSI. The incidence of SSI among nasal carriers of S. aureus was 12.5% and among carriers of MRSA it was 33%. Nasal carriage of S. aureus was found to be an independent risk factor for the development of SSI and also for increased mortality among this population. The authors admit that their study is small and that isolates from nasal screening were not compared with those responsible for the SSI. However, they recommend implementation of nasal screening and decolonisation in this population to reduce the incidence of SSI. Mun˜oz P, Hortal J, Giannella M, Barrio JM, Rodriguez-Cre´ixems, Pe´rez, Rinco´n C, Bouza E. Nasal carriage of S. aureus increases the risk of surgical site infection after major heart surgery. J Hosp Inf 2008; 68: 25–31.
Healthcare Infection
Budget impact analysis of rapid screening for Staphylococcus aureus colonization among patients undergoing elective surgery in US hospitals This article describes the development of a budget impact model to determine the impact of adding preadmission rapid testing for nasal carriage of Staphylococcus aureus and subsequent decolonisation therapy to the standard care for all patients scheduled for elective surgery. The authors used various national data sources to create the model. It was estimated that 7 181 484 patients were admitted to US hospitals for elective surgery in 2003. The prevalence of S. aureus colonisation was estimated from previous studies at 32.5% for the model. The sensitivity and specificity for the rapid diagnostic test were estimated at 52% and 85%, respectively, as obtained from the manufacturer of the test. Efficacy of decolonisation was estimated at 56.5% and the probability of developing a post-surgical S. aureus infection at 7.5% for carriers and 1.5% for non-carriers, all from previously published results. Outcomes taken into account for cost of infections were length of stay, cost and mortality and regression analyses were performed to attempt to control for fixed hospital effects and patient characteristics including age, gender and comorbidities. Screening and treatment costs were estimated based on the assumption that it would take a nurse 7.5 min to obtain a sample and on the costs of rapid diagnostic testing and decolonisation treatment in 2004.
rapid testing and decolonisation therapy for all patients scheduled to undergo elective surgery at $231 538 400 (95% CI 299 786 016–$1 330 255 360) for 2004. The mean annual number of hospital days were predicted to be reduced by 364 919 (95% CI 67 893–926 983) hospital days. The probability that net cost savings would result was estimated at 65%. A key driver of outcomes were found to be the efficacy of decolonisation therapy and for this analysis the authors state that their estimate of 56.5% was conservative, meaning a higher efficacy would result in greater savings. The prevalence of S. aureus carriage was another key driver suggesting that hospitals admitting a greater number of patients who are carriers have a higher potential for positive outcomes from these measures. The authors point out that the limitations of the study include use of a national perspective, whereas individual hospital cost savings may vary widely; testing did not consider different strains of S. aureus, and that the model focused only on testing of the nares and not other body sites. However, they also point out that their results are consistent with previous findings and that overall it would seem the model predicts that there is a high probability that screening and subsequent decolonisation would likely result in substantial cost savings for US hospitals. Noskin GA, Rubin RJ, Schentag JJ, Kluytmans J, Hedblom EC, Jacobson C, Smulders M, Gemmen E, Bharmal M. Budget impact analysis of rapid screening for Staphylococcus aureus colonization among patients undergoing elective surgery in US hospitals. Infect Control and Hosp Epid 2008; 29: 16–24.
Using relatively complex statistical analysis, the authors estimate the annual mean cost savings from pre-admission
23
Journal Watch Journal Watch presents a breif description of articles recently published in other journals and thought to be of relevance or interest to the AIC readership. Readers are encouraged to refer to the full article for complete information.
Elements of influenza vaccination programs that predict higher vaccination rates: results of an emerging infections network survey Following the Healthcare Infection Control Practices Advisory Committee (HICPAC) and the Advisory Committee on Immunization Practices (ACIP) release of recommendations designed to increase vaccination rates among health care workers (HCWs), 991 infectious diseases consultants were surveyed by the Infectious Diseases Society of America regarding vaccination programs at their respective institutions. The recommendations were formulated as a result of continuing low vaccination rates, and were evidence based. They include several specific measures aimed at encouraging vaccination, including education regarding the benefits of influenza vaccination, providing free vaccination and easy access, obtaining a signed declination form from HCWs who refuse vaccination and using the level of vaccination coverage as a measure of patient safety and quality of care. One aim of the survey was to examine the level of implementation of the recommendations. There were 418 valid responses to the survey. Vaccination rates for all health care workers in most institutions were between 41 and 60%. Logistic regression models were used to determine predictors of vaccination rates – and all program elements were significant predictors of vaccination rates in univariate analysis. Because the elements were highly associated with each other, another statistical method (principal components analysis) was used to find combinations of the elements that would serve as optimal predictors of higher vaccination rates. The results of the survey indicated that many hospitals have not completely implemented the HICPAC/ACIP recommendations. Almost all institutions provided vaccine free of charge to HCWs, and most (87%) offered the vaccine in locations convenient to HCWs; however, few offered vaccine at staff meetings or out of hours clinics. The two least implemented recommendations were requiring signed declination statements and practicing active surveillance for healthcare acquired influenza. Nine institutions reported that signed declinations would be required for the next season (2006/2007). Twenty one percent of respondents did not know their vaccination rates and 5% reported that rates could not be determined. Most (62%) vaccinated 60% of HCWs and only 10% reported rates 80%. Rates were significantly higher in institutions that required signed declination statements.
Australian Infection Control Association 2008
The principal components analysis suggested that the most effective elements for a successful vaccination campaign are: vaccine free of charge, devoting adequate resources to vaccination efforts and education of targeted groups of HCWs. The authors report being disappointed at the general low level of implementation of the recommendations and also that infectious diseases consultants generally support public reporting of institution vaccination rates. Polgreen PM, Chen Y, Beekmann S, Srinivasan A, Neill MA, Gay T, Cavanaugh JE. Elements of influenza vaccination programs that predict higher vaccination rates: results of an emerging infections network survey. Clin Inf Dis 2008; 46: 14–19.
Risk factors and recommendations for rate stratification for surveillance of neonatal healthcare-associated bloodstream infection The aim of this study was to assess key potential risk factors for bloodstream infection (BSI) in neonates and to determine those most appropriate for stratifying BSI rates and to enable valid comparisons between hospitals with differing case-mixes. The authors argue that due to the variation in case-mix between neonatal units, risk stratification should relate risks to neonates rather than to the unit as a whole, whereas the latter method is currently the method used by the English Nosocomial Infection National Surveillance Scheme. All 1367 babies admitted to the neonatal unit at a London Hospital over a 34-month period were followed from admission to discharge for development of BSI. The definitions for development of BSI used differ from National Healthcare Safety Network (NHSN) definitions. Data recorded included gender, gestational age, birthweight, postnatal age (recorded daily), endotracheal tube, nasal cunnulae, central vascular device, peripheral vascular device, parenteral nutrition, nasogastric tube and ‘receiving breast milk’. The relationship between BSI and birthweight, gestational age and postnatal age was considered unlikely to be linear so statistical techniques were used to fit a curve for each of these variables – each showed an initial curved relationship indicating a higher risk for lower birthweight, gestational age and postnatal age which then plateaued. For this reason these variables were modelled as categorical variables with three categories – high, medium, and falling to low risk as the curve levelled off.
DOI: 10.1071/HI08005
21
Healthcare Infection
Univariate Poisson regressions indicated that all risk factors except gender and exposure to breast milk in the previous 3 days were significantly associated with BSI, with the strongest associations being parenteral nutrition, birthweight <700 g, gestational age <26 weeks and central vascular device. Subsequent multiple regression analysis identified only parenteral nutrition within the preceding 3 days and gestational age <26 weeks as significant independent risk factors. The BSI rate was 40 times higher in infants with these two risk factors than in infants without these risk factors. Parenteral nutrition has now been recognised as a risk factor in several studies, and the authors argue that it could be a mistake that many surveillance programs for neonates focus primarily on the risks of intravascular catheters without considering the nature of the associated infusate. They suggest that given that at least in the UK, use of parenteral nutrition varies widely between institutions, any inter-hospital comparisons that do not take account of this as a risk factor would be invalid. The authors also recommend stratifying by gestational age but recognise that birthweight is easier to capture and might be a viable alternative. They acknowledge weaknesses in their study including the fact that it was single site and also the need for validation of their findings. Holmes A, Dore´ CJ, Saraswatula A, Bamford KB, Richards MS, Coello R, Modi N. Risk factors and recommendations for rate stratification for surveillance of neonatal healthcare-associated bloodstream infection. J Hosp Inf 2008; 68: 66–72.
Ventilator-associated pneumonia as a quality indicator for patient safety? This article discusses ventilator-associated pneumonia (VAP) and the concept of benchmarking in health care, particularly in relation to VAP. The authors argue against considering VAP rates as a potential candidate for benchmarking or for monitoring quality of patient care on the basis that at the present time, accurate benchmarking is not feasible. Reasons given for this argument include the difficulty with case definition and diagnosis and assessment of severity of pneumonia, the complexity of surveillance for VAP due to the need to access multiple data sources and case-mix complexities particularly in relation to critically ill patients. Alternatively it is suggested that some risk factors are modifiable and can be monitored and used as quality indicators. The main risk factors are listed in the article together with a measure of the strength of the evidence for each risk factor. Process improvements have been shown to reduce VAP rates, usually in studies where they have been implemented as ‘bundles’. Overall, they conclude that benchmarking VAP rates is hazardous and potentially misleading but that use of evidence-based process indicators as part of a well 22
defined surveillance system can serve as quality indicators and ultimately improve patient safety and quality of care. U¸c kay I, Ahmed QA, Sax H, Pittet D. Ventilator-associated pneumonia as a quality indicator for patient safety? Clin Inf Dis 2008; 46: 557–563.
Nasal carriage of S. aureus increases the risk of surgical site infection after major heart surgery This article describes a 1-year observational study during which patients undergoing major heart surgery (MHS) were screened for nasal carriage of Staphylococcus aureus before surgery. The authors contend that data on risks of surgical site infection (SSI) in nasal carriers is scarce but suggest that it may be a risk factor following cardiac surgery and they note that there are no commonly recognised guidelines that specifically recommend screening and decolonisation. The study aimed to determine the incidence of carriers in the population undergoing MHS at a 1750-bed tertiary referral teaching hospital in Spain and to assess the impact of nasal carriage on the incidence of SSI in these patients. Cases of SSI were recorded and risk factors of patients with and without SSI were analysed. There were a total of 357 patients include in the study of which 96 (27%) were found to be nasal carriers of S. aureus and nine of these had methicillin resistant strains (MRSA). Infections were diagnosed according to CDC criteria and superficial and deep incisional SSIs were included. Patients were not decolonised and vancomycin prophylaxis was not provided; however, contact precautions were taken with patients known to be MRSA carriers. Renal failure was found to be the only condition associated with increased risk (RR 2.3, 95% CI: 1.35–3.95) for nasal carriage of S. aureus. Risk factors associated with nasal carriage of MRSA were obesity (RR 5.07, 95% CI 1.29–20.0) and previous cerebrovascular accident (RR 4.99, 95% CI 1.2–18.8). Twenty three patients developed an SSI (6.4%). Fifteen (4.2%) had postsurgical mediastinitis and eight (2.2%) had a superficial SSI. The incidence of SSI among nasal carriers of S. aureus was 12.5% and among carriers of MRSA it was 33%. Nasal carriage of S. aureus was found to be an independent risk factor for the development of SSI and also for increased mortality among this population. The authors admit that their study is small and that isolates from nasal screening were not compared with those responsible for the SSI. However, they recommend implementation of nasal screening and decolonisation in this population to reduce the incidence of SSI. Mun˜oz P, Hortal J, Giannella M, Barrio JM, Rodriguez-Cre´ixems, Pe´rez, Rinco´n C, Bouza E. Nasal carriage of S. aureus increases the risk of surgical site infection after major heart surgery. J Hosp Inf 2008; 68: 25–31.
Healthcare Infection
Budget impact analysis of rapid screening for Staphylococcus aureus colonization among patients undergoing elective surgery in US hospitals This article describes the development of a budget impact model to determine the impact of adding preadmission rapid testing for nasal carriage of Staphylococcus aureus and subsequent decolonisation therapy to the standard care for all patients scheduled for elective surgery. The authors used various national data sources to create the model. It was estimated that 7 181 484 patients were admitted to US hospitals for elective surgery in 2003. The prevalence of S. aureus colonisation was estimated from previous studies at 32.5% for the model. The sensitivity and specificity for the rapid diagnostic test were estimated at 52% and 85%, respectively, as obtained from the manufacturer of the test. Efficacy of decolonisation was estimated at 56.5% and the probability of developing a post-surgical S. aureus infection at 7.5% for carriers and 1.5% for non-carriers, all from previously published results. Outcomes taken into account for cost of infections were length of stay, cost and mortality and regression analyses were performed to attempt to control for fixed hospital effects and patient characteristics including age, gender and comorbidities. Screening and treatment costs were estimated based on the assumption that it would take a nurse 7.5 min to obtain a sample and on the costs of rapid diagnostic testing and decolonisation treatment in 2004.
rapid testing and decolonisation therapy for all patients scheduled to undergo elective surgery at $231 538 400 (95% CI 299 786 016–$1 330 255 360) for 2004. The mean annual number of hospital days were predicted to be reduced by 364 919 (95% CI 67 893–926 983) hospital days. The probability that net cost savings would result was estimated at 65%. A key driver of outcomes were found to be the efficacy of decolonisation therapy and for this analysis the authors state that their estimate of 56.5% was conservative, meaning a higher efficacy would result in greater savings. The prevalence of S. aureus carriage was another key driver suggesting that hospitals admitting a greater number of patients who are carriers have a higher potential for positive outcomes from these measures. The authors point out that the limitations of the study include use of a national perspective, whereas individual hospital cost savings may vary widely; testing did not consider different strains of S. aureus, and that the model focused only on testing of the nares and not other body sites. However, they also point out that their results are consistent with previous findings and that overall it would seem the model predicts that there is a high probability that screening and subsequent decolonisation would likely result in substantial cost savings for US hospitals. Noskin GA, Rubin RJ, Schentag JJ, Kluytmans J, Hedblom EC, Jacobson C, Smulders M, Gemmen E, Bharmal M. Budget impact analysis of rapid screening for Staphylococcus aureus colonization among patients undergoing elective surgery in US hospitals. Infect Control and Hosp Epid 2008; 29: 16–24.
Using relatively complex statistical analysis, the authors estimate the annual mean cost savings from pre-admission
23