Healthcare-associated surgical site infection (HA SSI)

Risk of symptomatic infection and duration of disease

Deep, organ-space and superficial surgical site infections (SSIs) were defined in accordance with the ECDC case definition (ECDC, 2012).

In an attempt to provide an outcome tree reflecting the natural history of healthcare associated SSI, a systematic review of the literature was undertaken. During the initial search strategy, it became clear that it was impossible to obtain a full picture of all attributable deaths, complications, sequelae and length of hospital stay due to the heterogeneous nature of deep, organ-space and superficial SSIs.

We therefore decided to group all SSIs and focus on one sequelae: the proportion of case fatalities. The latter was set to 0.9% for patients aged under 65 years and to 3.6% for patients 65 years and over (Astagneau, 2001). However, this approach underestimated the burden of healthcare-associated SSI which would need to include long-term sequelae, such as mobility restrictions and reoperations following joint replacement surgery.

Model input summary

Table 1. Transition probabilities used in the outcome tree

 Health outcome
 (Health state)

Distribution of health states in health outcome

Transition probability

Source/assumption

Deaths following symptomatic infection

 

0.9% < 65
3.6% >= 65

Astagneau P, 2001

Table 2. Disability weights and duration

Health outcome
(Health state)

Disability Weight (DW) (Haagsma, 2015)

Duration

DW

Label

In years

Source/assumption

Symptomatic disease

0.051 (0.039-0.06)

Infectious disease, acute episode, moderate

0.096

Coskun, 2005

References

Astagneau P, Rioux C, Golliot F, Brucker G, Group INS. Morbidity and mortality associated with surgical site infections: results from the 1997-1999 INCISO surveillance. J Hosp Infect. 2001 Aug;48(4):267-74.

Coskun, D., Aytac, J., Aydinli, A., & Bayer, A. (2005). Mortality rate, length of stay and extra cost of sternal surgical site infections following coronary artery bypass grafting in a private medical centre in Turkey. J Hosp Infect, 60(2), 176-179.

European Centre for Disease Prevention and Control. Point prevalence survey of healthcare- associated infections and antimicrobial use in European acute care hospitals – protocol version 4.3. Stockholm: ECDC; 2012.

Haagsma JA, Maertens de Noordhout C, Polinder S, Vos T, Havelaar AH, Cassini A, Devleesschauwer B, Kretzschmar ME, Speybroeck N, Salomon JA. Assessing disability weights based on the responses of 30,660 people from four European countries. Population Health Metrics 2015; 13: 10