Serhat Ünal MD
Study Group on Nosocomial
European Society of Clinical
Microbiology and Infectious Diseases
Department of Internal Medicine
Faculty of Medicine
By the end of the 19th century, hospitals were dangerous places. There was little understanding of how infectious diseases were transmitted, hygiene was poor, and many died as a result of infections acquired during surgery or childbirth. However, improvements came with the growing understanding of the link between hygiene and infection, the use of antiseptics during surgery, and the discovery of penicillin in 1928. Since then, especially in the 1950s and 60s, new classes of antibiotics were developed faster than bacteria developed resistance to them. But the bugs have fast caught up, and by the 1980s and 1990s scientists were only managing to make improvements within classes.
The last 30 years of the 20th century saw the return of hospital-acquired infections (HAIs) as a major problem, of which methicillin-resistant Staphylococcus aureus (MRSA) has received the most media coverage. However, it is not the only multiple antibiotic-resistant organism and may not even be the most dangerous. Of perhaps even more concern is another – vancomycin-resistant enterococci (VRE).
The problem posed by such emerging organisms prompted the establishment of infection control network systems such as the Centers for Disease Control (CDC) in the US and the Public Health Laboratory Service (PHLS) – now the Health Protection Agency (HPA) – in the UK. The European Society of Clinical Microbiology and Infectious Diseases (ESCMID), founded in 1983, is a nonprofit organisation registered in Germany. The range of ESCMID’s commitments and activities has expanded significantly through the years, including the organisation or support of a wide variety of educational meetings – from courses for trainees to symposia on highly specialised microbiological or clinical topics. Through its study groups, ESCMID has had an impact on discussions and resolutions on a broad range of scientific and clinical issues. One of these study groups is the ESCMID Study Group on Nosocomial Infections (ESGNI), formed with the aim of studying all aspects of nosocomial infection that are particularly relevant for the sake and purposes of ESCMID and its membership, establishing essential links and networks, sharing expertise and knowledge with the membership, and developing continuous education in the field of nosocomial infections and infection control.
Scope of the problem
HAIs are, by definition, infections that are neither present nor incubating when a patient enters hospital. It is estimated that about 9% of inpatients in the UK have a HAI at any one time, a number comparable to that of other industrialised countries (see Table 1). An additional 10–60% of infections may present after discharge.
Their effects vary from discomfort for the patient to prolonged or permanent disability. A small proportion of patient deaths each year are primarily attributable to HAIs. Not all HAIs are preventable, since the very old, the very young, those undergoing invasive procedures and those with suppressed immune systems are particularly susceptible. HAIs are an important cause of morbidity and mortality and therefore should be rigorously controlled as part of the general duty of patient care. But HAIs also have a considerable “economic” impact on hospital services and on the costs of healthcare.
The economic consequences of HAIs
Measuring the costs of HAIs is difficult, and the financial impact varies between different healthcare systems. Nevertheless, in simple terms, HAIs can have the following economic consequences:
- Delays to patient discharge, resulting in increased “hotel” costs. In addition, the patient suffers additional costs due to increased absence from work, and relatives suffer costs of time and travel to visit the patient.
- Increased treatment costs (eg, increased drug therapy and increased numbers of procedures, including repeat surgery). The patient may be discharged from hospital while infected, and the increased treatment costs then fall on general practice or community services.
- Increasing numbers of laboratory and imaging investigations.
- Increased infection control costs, including epidemiological investigations and medical, nursing and management time.
- HAIs are often the subject of litigation, the costs of which may be huge.
Increased rates of HAI associated with blocked beds, closed wards and theatres result in increased unit costs for admissions and procedures, lengthening waiting lists and failure to complete contracts. All these have financial penalties. Patient morbidity resulting from HAI will also have large community and society costs that are difficult to quantitate but may have considerable impact. Also difficult to measure in economic terms is a loss of reputation – either for the whole hospital or for individual units – which has significant impact on contracts and patient referral.
Overall cost estimates
Although the measurement of costs caused by HAIs is difficult, a number of studies have shown the probable magnitude of the problem (see Table 2). A 1999 study looked at 4,000 adult patients in an English district general (community) hospital during 1994–1995, where 7.8% of patients were identified as having an HAI in hospital.(1) Patients with an HAI diagnosed in hospital remained there approximately 2.5 times longer than uninfected patients – an average of 11 additional days. Hospital costs were approximately 2.8 times greater than those for uninfected patients, averaging about €4,400 per case. Adjusted for age, sex, co-morbidity and other factors, the death rate was seven times higher for patients with HAI. The estimated costs of HAI to the hospital in the study totalled €5.27 million. Costs might be expected to be higher in tertiary referral hospitals. The extrapolated national annual cost burden of HAI for hospitals was about €1.46 billion – equivalent to about 1% of the total national hospital budget, or the resources of 27 400-bed general hospitals. The national annual postdischarge costs were estimated to be €82.3 million. This included general practice costs of €12.3 million, hospital outpatients €39 million and community nursing services €31 million. It was estimated that HAIs were the direct cause of about 5,000 deaths per annum in England (more than those caused by suicides or traffic accidents) and contributed to an additional 15,000. In the US, HAIs are among the top 10 causes of death.
The US Institute of Medicine estimates that preventable adverse patient events, including HAIs, are responsible for 44,000–98,000 deaths annually in the US at a cost of €13.5–23 billion. The US National Nosocomial Infection Surveillance system had a positive impact on reducing HAI rates in participating hospitals.
Cost of outbreaks
Several studies have attempted to measure the costs associated with hospital outbreaks of infection. Again, the costs are tentative and must be considered in relation to the healthcare system studied and the year of study. Nevertheless, the costs have again been shown to be considerable. It was estimated that the additional costs generated by a large outbreak of MRSA over three years in an English district general hospital totalled €585,000.(2) A smaller MRSA outbreak cost €10,000; however, an outbreak of multidrug-resistant Gram-negative infection increased costs by about €51,000 (at 1990 prices). A study measured the costs of MRSA in a Canadian hospital and calculated that MRSA cost all Canadian hospitals €61–86 million annually (at 1997 prices).(3)
Cost benefit of infection control
In the Study on the Efficiency of Nosocomial Infection Control (SENIC) of 1974–1983, US hospitals with one fulltime infection control nurse (ICN) per 250 beds, an infection control doctor (ICD), moderately intense surveillance and a system for reporting wound infection rates to surgeons reduced their HAI rates by 32%.(4) In the other hospitals, the HAI rate increased by 18%. The SENIC study estimated that the annual cost of HAI in US hospitals was €792 million. The cost of infection control teams (0.2 ICD, 1 ICN and 1 clerk per 250 beds) was €57 million per annum, only 7% of the infection costs. Therefore, if infection control programmes were effective in preventing only 7% of nosocomial infections (normally distributed), the costs of the programmes would be covered. A 20% effectiveness would save €158 million, while 50% would save €395 million (at 1975 prices).
The costs of HAI are huge and include patient morbidity and mortality, hospital and community medical costs, the impact of blocked beds and wider socioeconomic costs. The costs of infection control programmes and staffing are relatively small, and with only a small degree of effectiveness they can pay for themselves. Investment in infection control is therefore highly cost-effective.
- Plowman R, Graves N, Griffin M, et al. Socio-economic burden of hospital acquired infection. London: PHLS; 1999.
- Coello R, Glenister H, Fereres J, Bartlett C, Leigh D, Sedgwick J, Cooke EM.The cost of infection in surgical patients: a case-control study. J Hosp Infect 1993;25:239-50.
- Cox RA, Conquest C, Mallaghan C, Marples RR. A major outbreak of methicillin-resistant Staphylococcus aureus caused by a new phage-type (EMRSA-16). J Hosp Infect 1995;29:87-106.
- Kim T, Oh PI, Simor AE. The economic impact of methicillin-resistant Staphylococcus aureus in Canadian hospitals. Infect Control Hosp Epidemiol 2001;22:99-104.
- Haley RW, Quade D, Freeman HE, Bennett JV. The SENIC Project. Study on the efficacy of nosocomial infection control (SENIC Project). Summary of study design. Am J Epidemiol 1980;111:472-85.