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Duration of antibiotic treatment after appendicectomy for acute complicated appendicitis. BJS 2014; 101: 715-719.

Published: 26th March 2014

Authors: C. C. van Rossem, M. H. F. Schreinemacher, K. Treskes, R. M. van Hogezand, A. A. W. van Geloven

Background

Antibiotic treatment after appendicectomy for complicated appendicitis aims to reduce postoperative infections. However, available data on the duration of treatment are limited. This study compared the difference in infectious complications between two protocols, involving either 3 or 5 days of postoperative antibiotic treatment.

Method

This was an observational cohort study of all adult patients who had an appendicectomy between January 2004 and December 2010 at either one of two hospitals in the same region. At location A, the protocol included 3 days of postoperative antibiotic treatment, whereas at location B it specified 5 days. The primary outcome was the development of postoperative infections as either superficial wound infection or deep intra‐abdominal infections.

Results

A total of 1143 patients with acute appendicitis underwent appendicectomy, of whom 267 (23·4 per cent) had complicated appendicitis. The duration of postoperative antibiotic treatment was 3 days in 135 patients (50·6 per cent) and at least 5 days in 123 (46·1 per cent). No difference was found between antibiotic treatment for 3 or 5 days in terms of developing an intra‐abdominal abscess (odds ratio (OR) 1·77, 95 per cent confidence interval 0·68 to 4·58; P = 0·242) or a wound infection (OR 2·74, 0·54 to 13·80; P = 0·223). In patients with complicated appendicitis, the laparoscopic approach was identified as a risk factor for developing an intra‐abdominal abscess in univariable analysis (OR 2·46, 1·00 to 6·04; P = 0·049), but was not confirmed as an independent risk factor for this complication in multivariable analysis (OR 2·32, 0·75 to 7·14; P = 0·144).

Conclusion

After appendicectomy for complicated appendicitis, 3 days of antibiotic treatment is equally effective as 5 days in reducing postoperative infections.

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Your comments

4 Comments

Kirsty McFarlane

3 years ago

Dear Sir,

The recently published World Health Organisation’s global surveillance report on antimicrobial resistance has unveiled very startling and worryingly high levels of resistance all over the world (1). This is driven mainly by the overuse and misuse of antibiotics. Usage of appropriate antibiotics and for appropriate duration can serve as a very important tool in limiting this crisis. Van Rossem et al. have presented a very pertinent study, building a strong case for shorter duration of antibiotic usage in complicated acute appendicitis, thus supporting good antibiotic stewardship.

However, in their uni/multivariate analyses, for predicting risk factors for infectious complications, only a few variables seem to have been analysed. It would have been interesting to see if some more, yet relevant, factors were accounted for, such as time to initial intervention, co-morbidities, advanced age (rather than below or above 50 years), nutritional status, etc. (2). This could have potentially helped in identifying more variables that lead to infective complications.

In addition, their finding of higher incidence of intra-abdominal abscess with laparoscopy on univariate analysis could have been biased by the fact that surgeons were not as proficient when the laparoscopy was introduced in the study as there was a high conversion rate of 22%. As one climbs up the learning curve of laparoscopic surgical skills, it will be interesting to see if the univariate analysis still holds the ground in later years of the study, when the operative proficiency will presumably be comparable in both open and laparoscopic surgery and therefore infective complication rates might be comparable too. 

Aditya Kanwar
Tamsin Oswald
Sarah Robinson

Wansbeck Hospital
Northumbria NHS Trust
UK
adityakanwar@doctors.net.uk

References:
1. Antimicrobial resistance: global report on surveillance 2014. World health Organisation. (http://www.who.int/drugresistance/documents/surveillancereport/en/)
2. Solomkin JS, Mazuski JE, Bradley JS, Rodvold KA, Goldstein EJ, Baron EJ et al. Diagnosis and management of complicated intra-abdominal infection in adults and children: guidelines by the Surgical Infection Society and the Infectious Diseases Society of America. Clin Infect Dis 2010; 50: 133-164 (erratum in Clin Infect Dis 2010; 50: 1695).

Kirsty McFarlane

3 years ago

Dear Sir

We read with interest the recent paper by van Rossem et al. (1). We commend the authors’ efforts to examine the influence of antibiotic duration in emergency surgical patients, especially in the current climate of increasing antimicrobial resistance and financial pressures on healthcare systems. However, we would like to highlight a few additional points.

There was a significant difference in mean operating time for both open and laparoscopic appendicectomy between the two hospital sites. This suggests either a difference in the standard of surgery or operative experience between hospitals. Longer duration of surgery is known to be associated with increased surgical site infections (2). We were therefore disappointed that this confounding risk factor was not included in the multivariable analysis. Examination of other known risk factors for infection including co-morbid conditions (e.g. diabetes, obesity) and patient smoking status would also have been desirable.

The lack of robust follow-up data is also an important limitation of the study. The exclusion of outpatient and primary care data significantly diminishes the ability to capture vital information regarding the primary outcome measure of this study. As such, the true incidence of post-operative infective complications, especially superficial wound infections, is likely to have been significantly under-recorded in this study.

Shorter courses of antibiotics in the post-operative period are desirable. However, further higher quality evidence is required prior to the widespread adoption of shorter duration post-operative antibiotics after appendicectomy for complicated appendicitis.

Aonghus McGivney
Claire Arneil
Susan Moug
Sam Dockree
Sophie Flood
Chris Ray
Raymond Oliphant
On behalf of the RAH Virtual Journal Club

Department of General Surgery
Royal Alexandra Hospital
Corsebar Road
Paisley PA2 9PN
UK
raymondoliphant@nhs.net

References:
1. CC van Rossem, MHF Schreinemacher, K Treskes, RM van Hogezand, AAW van Geloven. Duration of antibiotic treatment after appendicectomy for acute complicated appendicitis. Br J Surg 2014; 101: 715-719.
2. G Leong, J Wilson, A Charlett. Duration of operation as a risk factor for surgical site infection: comparison of English and US data. J Hosp Infection 2006; 63: 255-262.

Kirsty McFarlane

3 years ago

Thank you for your comments about our study which highlights the importance of good antibiotic stewardship, and for your interest in potential additional factors that could affect complication rate after an appendicectomy.

We tried to identify the potential risk factors for complications after an appendicectomy for complicated appendicitis; for instance approach, age and antibiotic duration. Also, in advanced age (>70 years), there was no difference in infectious complications compared to younger patients, although this was a small group (31 patients). Comorbidity and nutritional status can obviously complicate recovery after any surgery, but most patients presenting with appendicitis are otherwise generally healthy. We believe that the most important risk factor for infection after surgery is the severity of appendicitis rather than other contributing factors. Antibiotics can reduce this, but more than a 3 day course will not provide further protection.

Only 32% of the patients with complicated appendicitis underwent a laparoscopic approach; of these 22% were converted to open (8% conversion rate for all laparoscopic surgery). Throughout the duration of the study no difference was seen in conversion rate between the first years and the last. This can be explained by the fact that the laparoscopic approach was gradually introduced among different surgeons; the learning curve effect was therefore maintained throughout the study. The conversion rate has subsequently decreased and this is the subject of study in our current prospective study.

Charles C. van Rossem
Anna A.W. van Geloven

Tergooi Hospital
Hilversum
The Netherlands
cvanrossem@tergooi.nl

Kirsty McFarlane

3 years ago

Dear colleagues,

The longer duration of surgery at location A is directly attributable to the main surgeon performing the appendicectomy for complicated appendicitis. Being the primary location for residents in surgery, at location A the main operator was a resident in 79% versus a consultant in 21% of the cases. At location B this number was the opposite, the main operator was a consultant in 71% versus a resident in 29% of the cases. The type of operator (resident or consultant), being collinear with the operating time, was included in both univariable and multivariable analysis and was not identified as a risk factor for developing an infectious complication (table 2).

We acknowledge that co-morbid conditions are risk factors for complications after any surgery. Co-morbid conditions are not reported in our study but are likely to be equally divided between the locations because of equally divided demographical data (sex and age) and because of the proximity of the hospitals with a similar population. Co-morbid disease is expected more in advanced age whilst appendicitis is a more rare condition in advanced age (only 6.5% above 70 years of age in our cohort).

In the discussion, we mention the possible underreported superficial wound infection rate because of lack of outpatient clinical data. However, all clinical significant infectious complications for which re-intervention, readmission or antibiotic treatment was necessary were detected in our electronic patient database system. It is unlikely that patients present themselves to primary care and being treated for a clinical significant wound infection without further referral.

Charles C. van Rossem
Anna A.W. van Geloven

Department of Surgery
Tergooi Hospital
1201 DA Hilversum
The Netherlands
cvanrossem@tergooi.nl