Evaluation of Cost of Nosocomial Infection: Summary for Participants



Every year in Scotland there are about 700,000 overnight admissions to hospital. A small number of patients go on to develop infections during their hospital stay. These infections are known as nosocomial infections (NI) or healthcare associated infections (HAI). These NI can cause the patient to stay in hospital longer and which can lead to delays in treating other patients. We will use the shortened term NI throughout the paper when referring to nosocomial infection.

Within Scotland a range of infection prevention and control measures have been used to reduce the risk of NI. It is important to understand who is affected, when and where, what types of infection they get. Knowing this helps when deciding which measures should be used and where.

Nosocomial infection can happen while a patient is in hospital or just after they leave.

There are lots of reasons why someone can develop an infection. Being ill or receiving healthcare can make your natural defence system (immune system) weaker than usual. Most people will not pick up an infection while they are being treated, but it is impossible to prevent all NI. Reducing the risk of patients getting NI during healthcare is a critical part of patient safety.

NI describes multiple infection types which can affect any part of the body. These infections range from urinary tract infections which may require treatment with a course of antibiotics, to more serious life threatening blood stream infections.

NI are a concern as they can affect a patient’s recovery, and lead to poorer health. They may also lead to extra treatments with antibiotics or surgery. Tackling these infections is a key priority for the Scottish Government and NHS Scotland in terms of the safety and wellbeing of patients, staff and the public.

The aim of the study was to investigate the cost and impact of these infections on patients, the health service and the wider community. To do this information was collected about people who developed an NI and those who did not. Understanding the incidence (or total number of cases that arise in a year in hospitals) of NI and what happens to patients will help to target infection prevention and control measures to those patients who would benefit the most.

The European Centre for Disease Prevention and Control (ECDC) estimates that on any given day 1 in 18 patients who are in hospital in the Europe have NI. This means that across Europe on any given day, eighty thousand patients have an NI. These estimates arise from prevalence surveys which are a snapshot of infections at a given time.

A National Point Prevalence Survey (PPS) happens every five years in Scotland to look at NI and antimicrobial prescribing. Point prevalence surveys (PPS) are a snapshot of hospital patients with a NI at the time of survey. The last PPS in 2016 found that roughly one in every 22 adult inpatients in a hospital in Scotland had a NI at the time of survey. We know these surveys are limited and changes in reasons for admission and types of infection throughout the year, for example more respiratory infection in winter, can impact on these estimates.

For one year starting in April 2018 a team of specially trained research nurses based in two Scottish hospitals looked at every suspected NI. All suspected cases were compared to a standard definition, used throughout the world, to diagnose nosocomial infection. When the cases met the definition the research nurses recorded the type of NI, the organism that caused the infection and how long the infection lasted. This information linked to hospital records of all patient admissions which allowed us to investigate the impact of NI on patients stay in hospital. The study reports incidence of NI, which is the proportion of new cases of NI in the hospital population. The study was managed by Glasgow Caledonian University (GCU).

One in every hundred patients treated developed an NI during the study or alternatively for every 100,000 occupied bed days there were 250 NIs.

The risk of developing NI increased with age, with those over 80 years at two and a half times greater risk of developing NI compared with those under 40 years. About one third (29%) of NI were found in patients aged over 80 years. Risk of NI in emergency admissions was twice that of planned admissions.

NI was most common in special types of wards such as intensive care/high dependency, renal medicine and cardiothoracic surgery. This reflects the higher risks of the patients in these settings who are often immunocompromised and therefore at risk of acquiring infection. There is also a higher level of invasive treatments which are risk factors for infection, which happen in these settings.

Urinary tract infection was the most commonly occurring NI, followed by blood stream infection, lower respiratory tract infection, gastrointestinal infection, surgical site infection, and pneumonia. Different organisms (or bugs) can cause NI, but most commonly the NI were caused by Escherichia coli, Staphylococcus aureus and Norovirus.

Patients who developed NI stayed in hospital an average of eight days longer than patients of similar age, and conditions.

Pneumonia showed the longest average additional time spent in hospital (16 days). However, blood stream infections cause the greatest total length of stay because there are a greater number of infections.

All patients in the study reported lower quality of life than the general population. The impact of the NI was difficult to distinguish from the conditions that brought them into hospital. Due to there not being large numbers of NI patients and the frailty of those patients who had NI, it was challenging to recruit enough patients to allow detailed analysis of how NI affected their quality of life by infection type or any level of detail.

We estimated that within NHS Scotland there are 7,500 NI cases annually. From this it was estimated that in Scotland, on average, 58,000 bed days are occupied by patients who developed NI each year. This is equivalent to a small general hospital being used to treat only patients with NI all year.

It is estimated that NI treatment cost £46.4 million during 2018/2019 in Scotland.

Bloodstream infection and pneumonia were the highest costed NI types per case.

The total annual cost in the UK is estimated to be £774 million, but could be higher.

The average cost for treatment of patients with NI, three months after leaving hospital was just under £1500. Patients with NI were given more antibiotics in the community and stayed three days longer on average than patients without NI if they were re-admitted to hospital. The majority (95%) of the excess costs was on acute care services after re-admission. Bloodstream infection, gastrointestinal infection and pneumonia had the biggest impact on costs after a patient was discharged from hospital.

Identifying patients who are at greater risk of developing NI at the start of their hospital stay and managing their care to reduce their risk of developing NI is critical.

Patients who at the point of admission are: treated in a teaching hospital, of older age, have cancer, cardiovascular disease, chronic renal failure or diabetes; and are admitted as an emergency, have a higher risk of developing NI. Knowing which patients are most at risk of different types of NI could allow personalised infection prevention measures to used.

In addition to identifying patients at higher risk, it is important that all healthcare staff prevent NI transmission by following infection prevention and control measures for all patients during their stay, in line with the national guidance which can be found here: https://www.nipcm.hps.scot.nhs.uk/.

We can all help prevent NI by following the infection prevention and control advice we are given by staff when in hospital as a patient or when visiting a hospital. These include hand hygiene and not visiting someone else in hospital if you are unwell. The current measures we can all use currently, which have been introduced during the COVID-19 pandemic, are available here: https://www.gov.scot/news/visiting-family-and-friends-in-hospital.

If the NHS in Scotland could reduce the numbers of HAI by 10%, there is the potential to free enough hospital resources to treat an average of 1,706 patients receiving planned treatment in hospital. This would reduce waiting lists, which is really important for patient care and especially in the context of the COVID-19 pandemic legacy on the NHS.

The findings of the study have been shared with:

  • The hospitals that took part in the study
  • The national organisations responsible for Infection Prevention and Control (IPC) guidance
  • The Chief Nursing Officers (CNO) Healthcare Associate Infection (HAI) policy unit within the Scottish Government (SG).

The Glasgow Caledonian University (GCU) website contains links to the findings of the ECONI stud which have been published in peer-reviewed journals. https://www.gcu.ac.uk/hls/econi/newsandpublications/


A number of articles have been published already:

  1. Manoukian S, Stewart S, Dancer S, Graves N, Mason H, McFarland A, Robertson C, Reilly J. Estimating excess length of stay due to healthcare-associated infections: a systematic review and meta-analysis of statistical methodology. J Hosp Infect. 2018 Oct;100(2):222-235. doi: 10.1016/j.jhin.2018.06.003. Epub 2018 Jun 11. PMID:29902486.
  2. Stewart S, Robertson C, Manoukian S et al. How do we evaluate the cost of nosocomial infection? The ECONI protocol: an incidence study with nested case-control evaluating cost and quality of life. BMJ Open 2019; 9: e026687. doi:10.1136/bmjopen-2018-026687
  3. Stewart S, Robertson C, Pan J, Kennedy S, Dancer S, Haahr L, et al. Epidemiology of healthcare-associated infection reported from a hospital-wide incidence study: considerations for infection prevention and control planning. J Hosp Infect 2021. pp. 10-22 https://doi.org/10.1016/j.jhin.2021.03.031
  4. Stewart S, Robertson C, Pan J, Kennedy S, Haahr L, Manoukian S, et al. Impact of healthcare-associated infection on length of stay. J Hosp Infect 2021. pp. 23-31 https://doi.org/10.1016/j.jhin.2021.02.026
  5. Stewart S, Robertson C, Kennedy S, Kavanagh K, Haahr L, Manoukian S, et al. Personalised infection prevention and control: identifying patients at risk of healthcare-associated infection. J Hosp Infect 2021. pp. 32-42 https://doi.org/10.1016/j.jhin.2021.03.032
  6. Manoukian S, Stewart S, Graves N, Mason H, Robertson C, Kennedy S, et al. Bed-days and costs associated with the inpatient burden of healthcare-associated infection in the UK. J Hosp Infect 2021. pp. 43-50 https://doi.org/10.1016/j.jhin.2020.12.027
  7. Manoukian S, Stewart S, Graves N, Mason H, Robertson C, Kennedy S, et al. Evaluating the post-discharge cost of healthcare-associated infection in NHS Scotland. J Hosp Infect 2021. pp. 51-58. https://doi.org/10.1016/j.jhin.2020.12.026



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