Burden of surgical site infections in the Netherlands: cost analyses and disability-adjusted life years

Summary

Background

Surgical site infections (SSIs) are associated with morbidity, mortality and costs.

Aim

To identify the burden of (deep) SSIs in costs and disability-adjusted life years (DALYs) following colectomy, mastectomy and total hip arthroplasty (THA) in the Netherlands.

Methods

A retrospective cost-analysis was performed using 2011 data from the national SSI surveillance network PREZIES. Sixty-two patients with an SSI (exposed) were matched to 122 patients without an SSI (unexposed, same type of surgery). Patient records were studied until 1 year after SSI diagnosis. Unexposed patients were followed for the same duration. Costs were calculated from the hospital perspective (2016 price level), and cost differences were tested using linear regression analyses. Disease burden was estimated using the Burden of Communicable Disease in Europe Toolkit of the European Centre for Disease Prevention and Control. The SSI model was specified by type of surgery, with country- and surgery-specific parameters where possible.

Findings

Attributable costs per SSI were €21,569 (THA), €14,084 (colectomy) and €1881 (mastectomy), mainly caused by prolonged length of hospital stay. National hospital costs were estimated at €10 million, €29 million and €0.6 million, respectively. National disease burden was greatest for SSIs following colectomy (3200 DALYs/year, 150 DALYs/100 SSIs), while individual disease burden was highest following THA (1200 DALYs/year, 250 DALYs/100 SSIs). For mastectomy, these DALYs were <1. The total cost of DALYs for the three types of surgery exceeded €88 million.

Conclusion

Depending on the type of surgery, SSIs cause a significant burden, both economically and in loss of years in full health. This underlines the importance of appropriate infection prevention and control measures.

Introduction

Surgical site infections (SSIs) are frequently occurring nosocomial infections, accounting for approximately 25–30% of hospital-acquired infections (HAIs) [1]. In the Netherlands, 0.9–19.6% of all surgical patients will develop an SSI, depending on the type of surgery [2]. SSIs can have major implications for patients, hospitals and society; they increase morbidity as well as mortality [3], and as such may contribute to the burden on society in terms of healthcare costs (economic burden) and loss of years experienced in full health [disease burden, commonly measured in disability-adjusted life years (DALYs)]. As part of a larger European project on the disease burden of HAIs, a disease progression model was developed estimating that SSIs cause 58 DALYs per 100,000 European inhabitants, with 0.5 DALYs per SSI [4]. However, this estimate was based on SSIs in general, without distinction by type of surgery, while it is likely that the burden of disease varies between different types of surgery.

SSIs may also result in excess healthcare utilization and costs. With increasing overall healthcare costs, hospitals are encouraged to use their resources more efficiently and to avoid preventable costs. Currently, knowledge on the costs of SSIs in the Netherlands is limited. In 1996, a Dutch paper [5] estimated the attributable costs of an SSI following cardiothoracic surgery to be $16,878. A few years later, Geubbels estimated the cost of a superficial SSI to be between €900 and €2600, and that of a deep SSI to be between €3200 and €19,900 [6]. This study, however, based the costs of extra care on several assumptions and reported data on surgical specialty level instead of surgery level. Previous international studies have shown that costs can double, triple or even increase six-fold for patients with an SSI compared with patients without an SSI [7], [8], [9], depending on the type of surgery, setting and type of infection. The increased length of stay (LOS) is responsible for the majority of additional healthcare costs [10], [11], [12], [13], followed by parenteral medication and additional surgical procedures [14], [15]. However, due to different international healthcare systems and healthcare financial systems, costs calculated in these mostly UK- and US-based studies cannot be translated directly to the Dutch setting. Moreover, studies vary greatly in methodology, including evaluated cost components and unit costs [7]. Hence, to obtain useful estimates, country-specific data and surgery-type-specific data should be assessed for the Netherlands.

As such, this study determined the burden of disease in DALYs and the hospital costs for (deep) SSIs following three different, but commonly performed, types of surgery: colectomy, mastectomy and total hip arthroplasty (THA).