Risk factors for wound infection after minor surgery in general practice.
ABSTRACT To determine the incidence of and risk factors for surgical site infections in general practice.
Prospective, observational study of patients presenting for minor excisions.
Primary care in a regional centre, Queensland, October 2004 to May 2005.
857 patients were assessed for infection.
The overall incidence of infection was 8.6% (95% CI, 3.5%-13.8%). Excisions from lower legs and feet (P = 0.009) or thighs (P = 0.005), excisions of basal cell carcinoma (P = 0.006) or squamous cell carcinoma (P = 0.002), and diabetes (P < 0.001) were independent risk factors for wound infection.
Our results indicate the high-risk groups for surgery in a general practice setting, such as people with diabetes and those undergoing excision of a non-melanocytic skin cancer or excision from a lower limb. Recognition of these groups could encourage more judicial use of prophylactic antibiotics and use of other interventions aimed at reducing infection rates.
- SourceAvailable from: PubMed Central[Show abstract] [Hide abstract]
ABSTRACT: To determine the effectiveness of a single perioperative prophylactic 2 g dose of cephalexin in preventing surgical site infection (SSI) following excision of skin lesions from the lower limb.BMJ Open 07/2014; 4(7):e005270. · 2.06 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Objectives. Although the incidence of skin cancers in India (part of South Asia) is low, the absolute number of cases may be significant due to large population. The existing literature on BCC in India is scant. So, this study was done focusing on its epidemiology, risk factors, and clinicopathological aspects. Methods. A hospital based cross-sectional study was conducted in Punjab, North India, from 2011 to 2013. History, examination and histopathological confirmation were done in all the patients visiting skin department with suspected lesions. Results. Out of 36 confirmed cases, 63.9% were females with mean ± SD age being years. Mean duration of disease was 4.7 years. Though there was statistically significant higher sun exposure in males compared to females ( value being 0.000), BCC was commoner in females, explainable by intermittent sun exposure (during household work in the open kitchens) in women. Majority of patients (88.9%) had a single lesion. Head and neck region was involved in 97.2% of cases, with nose being the commonest site (50%) with nodular/noduloulcerative morphology in 77.8% of cases. Pigmentation was evident in 22.2% of cases clinically. Nodular variety was the commonest histopathological variant (77.8%). Conclusions. This study highlights a paradoxically increasing trend of BCC with female preponderance, preferential involvement of nose, and higher percentage of pigmentation in Indians.Journal of Skin Cancer. 11/2014;
- [Show abstract] [Hide abstract]
ABSTRACT: Objectives. Although the incidence of skin cancers in India (part of South Asia) is low, the absolute number of cases may be significant due to large population. The existing literature on BCC in India is scant. So, this study was done focusing on its epidemiology, risk factors, and clinicopathological aspects. Methods. A hospital based cross-sectional study was conducted in Punjab, North India, from 2011 to 2013. History, examination and histopathological confirmation were done in all the patients visiting skin department with suspected lesions. Results. Out of 36 confirmed cases, 63.9% were females with mean ± SD age being 60.9 ± 14.2 years. Mean duration of disease was 4.7 years. Though there was statistically significant higher sun exposure in males compared to females (P value being 0.000), BCC was commoner in females, explainable by intermittent sun exposure (during household work in the open kitchens) in women. Majority of patients (88.9%) had a single lesion. Head and neck region was involved in 97.2% of cases, with nose being the commonest site (50%) with nodular/noduloulcerative morphology in 77.8% of cases. Pigmentation was evident in 22.2% of cases clinically. Nodular variety was the commonest histopathological variant (77.8%). Conclusions. This study highlights a paradoxically increasing trend of BCC with female preponderance, preferential involvement of nose, and higher percentage of pigmentation in Indians.Journal of skin cancer. 01/2014; 2014:173582.
MJA • Volume 185 Number 5 • 4 September 2006
The Medical Journal of Australia ISSN:
0025-729X 4 September 2006 185 5
©The Medical Journal of Australia 2006
to be poor,7 and a comprehensive
MEDLINE search revealed only one study
that adequately recorded the incidence of
infection following minor surgery in general
Skin excisions form a large proportion of
a typical Australian general practitioner’s
workload, and this proportion is even
greater in Queensland.9 In north Queens-
land, most suspicious skin lesions are man-
aged by GPs,10 particularly in rural centres
such as Mackay, where there is no resident
dermatologist. There is evidence that per-
forming minor surgery in general practice is
cost-effective compared with a hospital set-
ting.11 However, it is important to know the
incidence of and risk factors for complica-
tions such as infection following minor sur-
gery in general practice.
The data for this study were collected
incidentally as part of a randomised control-
led trial, which compared the standard man-
agement of keeping wounds dry and
covered with allowing wounds to be uncov-
ered and wet in the first 48 hours following
minor surgery.12 As both arms of the trial
showed equivalent infection rates at the 5%
significance level (intervention, 8.4%; con-
trol, 8.9%), they have been considered as a
single group for the purpose of this study.
Our aims in this study were to determine
the incidence of and risk factors for surgical
site infections following minor skin exci-
sions in a primary care setting.
urgical site infection following minor
surgery contributes to patient morbid-
ity and compromises the cosmetic
outcome. Most data regarding incidence
and predictors of surgical site infection are
based on hospital studies,1-3 and most stud-
ies looking at infection rates following
minor dermatological surgery outside hos-
pital have been conducted in specialist der-
matology clinics.4-6 In contrast, the quality
of evidence regarding infection rates follow-
ing minor surgery in general practice seems
The methods for our prospective study of
patients presenting for minor skin excisions,
conducted initially as a randomised controlled
trial, have been described in detail else-
where.12 Here we provide a general overview.
Setting and participants
Nineteen GPs from four practices in the
Mackay area participated. Consecutive
patients presenting for minor skin excisions
between October 2004 and May 2005 were
invited to take part. Practice nurses were
responsible for recruiting patients and collect-
ing demographic and clinical data. A body site
map was used to define excision sites.
All patients presenting to a participating GP for
“minor skin excision” (except for skin exci-
sions on the face) were eligible to participate.
Patients were excluded if they were already
taking oral antibiotics, if oral or topical antibi-
otics were clinically indicated immediately
postoperatively, or if they were taking immu-
nosuppressive drugs. Further exclusion crite-
ria were lacerations, having a flap or two-layer
procedure, and excision of sebaceous cysts
(which were often already infected).
Surgical wound management protocol
Three 1-hour workshops were conducted for
participating GPs to develop guidelines to
ensure that excisions were managed in a stand-
Wounds were assessed for infection by the
practice nurse or doctor on the day of removal
of sutures, or sooner if the participant re-
presented with a perceived infection.
We used a definition of wound infection
adapted from standardised surveillance criteria
for defining superficial surgical site infection,
which we felt to be the closest to a “gold
standard” available (Box 1).1
Incidence of infection is given with 95% confi-
dence intervals. Numerical data are summa-
rised using mean (SD) when normally
distributed, or median and interquartile range
(IQR) when skewed.
Bivariate comparisons were conducted
using χ2 tests (two categorical variables) and
unpaired t tests or non-parametric Mann–
Whitney tests (categorical and numerical
Multivariable generalised linear modelling
was used to identify independent risk factors
of infection after minor surgery. Relative risks
with 95% confidence intervals were estimated
using the binomial distribution and the loga-
rithmic link function. All variables that were
not part of the final model (age, sex, month
excision took place, management of wound,
and significant medical condition other than
diabetes) were assessed for potential con-
founding of the relationships between body
site of skin lesion, histology of skin lesion, and
diabetes with wound infection.
Risk factors for wound infection after minor surgery
in general practice
Clare Heal, Petra Buettner and Sheldon Browning
Objective: To determine the incidence of and risk factors for surgical site infections in
Design: Prospective, observational study of patients presenting for minor excisions.
Setting: Primary care in a regional centre, Queensland, October 2004 to May 2005.
Participants: 857 patients were assessed for infection.
Results: The overall incidence of infection was 8.6% (95% CI, 3.5%–13.8%). Excisions
from lower legs and feet (P=0.009) or thighs (P=0.005), excisions of basal cell carcinoma
(P=0.006) or squamous cell carcinoma (P=0.002), and diabetes (P<0.001) were
independent risk factors for wound infection.
Conclusion: Our results indicate the high-risk groups for surgery in a general practice
setting, such as people with diabetes and those undergoing excision of a non-
melanocytic skin cancer or excision from a lower limb. Recognition of these groups
could encourage more judicial use of prophylactic antibiotics and use of other
interventions aimed at reducing infection rates.
MJA 2006; 185: 255–258
256MJA • Volume 185 Number 5 • 4 September 2006
The statistical analysis took the cluster sam-
pling design (four doctors’ practices) into
account. Throughout the analysis, P values less
than 0.05 (two-sided hypotheses) were con-
The statistical analysis was conducted
using SPSS for Windows, release 12 (SPSS
Inc, Chicago, Ill, USA) and Stata for Win-
dows, release 8 (StataCorp, College Station,
Participating GPs were younger (median
age, 44 years) and more predominantly
female (64%) than average for Australian
GPs (modal age category, 45–54 years; 32%
Of 1247 patients who attended for skin
excisions during the collection period from
October 2004 to May 2005, 377 were
excluded (294 ineligible; 83 non-partici-
pants) (Box 2). There were no significant
differences in the age (participants, 56.3
years [SD, 16.5]; non-participants, 58.1
years [SD, 16.2]; P=0.208) and sex (partic-
ipants, 47.6% female; non-participants,
44.9% female; P=0.407) of participating
and non-participating patients.
Thirteen patients were eventually lost to
follow-up. Follow-up was completed in 857
Infection occurred in 74 of the 857 exci-
sions (8.6%; 95% CI, 3.5%–13.8%). Infec-
tion rates for the four centres were 2.9%,
7.8%, 10.0%, and 10.2% (P=0.0496). Of
all characteristics recorded, only the pres-
ence of diabetes was significantly correlated
with a higher incidence of infection (diabe-
tes, 18.2%; no diabetes, 8.4%; P=0.019)
(Box 3). Participants older than 60 years
had a higher incidence of wound infection
(12.4%) than younger participants (5.6%)
(P=0.056). Squamous cell carcinomas were
most prone to be infected (13.5%), and
benign naevi (2.5%) and seborrhoeic kera-
toses (0) were least likely to become
infected. Of the 74 infections, 25 (34%)
occurred on the lower leg (below the knee)
or foot. There was little variation in inci-
dence of infection with the month in which
the excision took place, with no evidence of
increased infection during the hotter wet
season (P=0.527). There was no significant
difference in time to removal of sutures
between the infected and non-infected
groups (median, 8 days, IQR, 7–10 days for
both groups; P=0.538).
Multivariable generalised linear modelling
showed that the body sites legs and feet (P=
0.009) and thighs (P=0.005); the histologi-
cal subtypes basal cell carcinoma (P=0.006)
and squamous cell carcinoma (P=0.002);
and prevalence of diabetes (P<0.001) were
independently correlated with wound infec-
tion (Box 4).
Our results suggest that diabetes, excisions
from the lower leg and foot or thigh, and
excisions of non-melanocytic skin cancer
(squamous cell carcinoma and basal cell
carcinoma) are independent risk factors for
infection after minor surgery. The latter find-
ing is consistent with a study conducted in a
specialist dermatology clinic, which sug-
gested that oncological surgery (excision of
3 Bivariate correlates between
infection after minor surgery
and participant and lesion
Scalp and neck 10.6%0.072
Arms and hands6.8%
Legs and feet 15.0%
Histology of lesion
Basal cell carcinoma11.4%
Squamous cell carcinoma13.5%
Date of excision
Wet season (December to
Other medical condition*
*Medical conditions recorded were chronic
obstructive pulmonary disease (8), anaemia (1),
“aspirin” (2), “steroids” (3), “warfarin” (2), ischaemic
heart disease (1), and peripheral vascular disease (1).
Results were adjusted for the cluster sampling
1 Definition of superficial surgical site
• Infection must occur within 30 days of
• There must be purulent discharge from
the wound, or the general practitioner
must diagnose a wound infection, or the
GP commences antibiotics.
• Stitch abscess must not be counted as an
*Adapted from the Centers for Disease Control
and Prevention’s National Nosocomial Infections
2 Reasons for exclusion of 377
patients from study
Not returning for
removal of sutures*
*These five patients knew that they would not be
able to return for the removal of sutures. †The
practice nurse forgot to invite these patients to
MJA • Volume 185 Number 5 • 4 September 2006
skin cancer) is associated with a higher risk
of infection.13 Body extremities, with
reduced blood supply, have also previously
been associated with a higher incidence of
The overall incidence of infection in our
study (8.6%) was higher than we expected
from published results in a similar general
practice cohort (1.9%)8 and a similar der-
matology clinic cohort (2%),4 although
exclusion of facial excisions from our study,
which may have a lower incidence of infec-
tion,13 may have falsely elevated our overall
incidence of infection. Excluding patients
for whom antibiotics would otherwise have
been indicated postoperatively would, how-
ever, have lowered the infection rate. A
German study in a university medical cen-
tre setting reported a similar infection rate
of 8%.6 However, it is difficult to compare
the infection rate between different studies
as different variables and methods were
Our study had several limitations. There
are various characteristics influencing the
occurrence of infections and, although
information on as many variables as possible
was recorded, it proved difficult to ensure
that all possible predictors of infection were
recorded. There were inadequate data
recorded on suture size and patient occupa-
tion, and consequently, these factors could
not be compared. We did not record smok-
ing status, which may be a risk factor for
surgical site infections.1,14 We also did not
record the size of lesion excised, excision
margins or overall wound area, and there-
fore we are unable to exclude the possibility
that the increase in incidence of infection
recorded for squamous cell carcinomas and
basal cell carcinomas could be related to the
size of the overall wound area rather than
the histology. However, there is some evi-
dence that more complicated procedures
(flaps or skin grafts) are associated with
increased infection rates, rather than the size
of the excision.4 Exclusion of facial excisions
and more complicated surgery such as flap
or two-level procedures prevented analysis
of infection rates in these subgroups, and
Although diabetes was found to be inde-
pendently correlated with wound infection,
the prevalence of diabetes as well as other
medically important conditions was proba-
bly under-recorded, and power was limited
to analyse these subgroups.
Surgical training and technique of the GPs
involved are potential confounders which
would be difficult to quantify and were not
recorded. The differences in infection rates
we observed between centres have to be
seen as resulting from a combination of
patient, wound, and treatment factors, as
well as doctor factors.
The diagnosis of infection, even when
using guidelines, is still subjective, and has
inter- and intra-observer variation.15 The
definition of infection we used has limita-
tions, but it is the most widely implemented
standard definition of wound infection,15
and was as close to a gold standard as we
could find. We have no information regard-
ing intra- and inter-practice reproducibility
of measurement and recording procedures.
In addition, there are some limits to gen-
eralising these findings. The GPs involved
were not representative of Australian GPs,
being younger and more predominantly
female.16 The population of Mackay is
slightly older and has a lower median
household income than the Australian pop-
ulation.17 Mackay is a provincial town in
tropical north Queensland and has a hot and
humid climate, with the mean daily maxi-
mum temperature ranging between 24°C
4 Multivariable generalised linear modelling of relation between infection after
minor surgery and participant and lesion characteristics
Basal cell carcinoma
Squamous cell carcinoma
Legs and feet
Date of excision
Wet season (December to
Other medical condition*
*Other medical conditions recorded were chronic obstructive pulmonary disease (8), anaemia (1), “aspirin” (2),
“steroids” (3), “warfarin” (2), ischaemic heart disease (1), and peripheral vascular disease (1). The model was
adjusted for the cluster sampling design and for the confounding effects of age and sex of the participants.
Date of excision, presence of other medical condition, and wound management were not part of the model.◆
258MJA • Volume 185 Number 5 • 4 September 2006
and 30°C during the summer months, and a
relative humidity of 75%–79%.18 Our find-
ings may not be generalisable to a temperate
climate, although there is no published evi-
dence that heat and humidity increase infec-
Antibiotic prophylaxis is probably pre-
scribed excessively or inappropriately for
dermatological surgery,1,19 and is thought to
be best reserved for high-risk patients.19,20
There are no data available on the current
prescribing habits of Australian GPs regard-
ing antibiotic prophylaxis for minor exci-
sions. Although there is also no evidence
available regarding what reduction in the
rate of infection we might reasonably expect
from the use of prophylactic antibiotics for
minor excisions, there is some evidence of a
50% reduction in risk of infection when
perioperative antibiotic prophylaxis is used
following clean surgery.21 In addition to
efficacy, antibiotic costs, adverse effects and
resistance must be taken into account when
considering their use prophylactically. How-
ever, our results could encourage more judi-
cial use of prophylactic antibiotics by
defining high-risk groups for infection in a
general practice setting, such as people with
diabetes and those undergoing excision of a
non-melanocytic skin cancer or excision
from a lower limb. Alternatively, other non-
pharmaceutical interventions aiming to
reduce infection rates could be targeted
towards these high-risk groups.
We thank the participating GPs and practice
nurses. This project was funded by a Novice
Researcher scholarship from the Primary Health
Care Research, Evaluation and Development fund
through James Cook University. We also thank Ms
Lisa Crossland for her support as Primary Health
Care Research, Evaluation and Development co-
Clare Heal, MBChB, DRACOG, FRACGP,
Petra Buettner, MSc, PhD, Senior Lecturer1
Sheldon Browning, DRACOG, DipDerm,
FRACGP, General Practitioner2
1 James Cook University, Mackay, QLD.
2 Mackay, QLD.
1 Mangram AJ, Horan TC, Pearson ML, et al.
Guideline for prevention of surgical site infec-
tion, 1999. Infect Control Hosp Epidemiol 1999;
2 Cruse JE, Foord R. The epidemiology of wound
infection. Surg Clin North Am 1980; 60: 27-40.
3 Nguyen D, MacLeod WB, Phung DC, et al.
Incidence and predictors of surgical-site infec-
tions in Vietnam. Infect Control Hosp Epide-
miol 2001; 22: 485-492.
4 Amici J, Rogues A, Lasheras A, et al. A prospec-
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Dermatol 2005; 153: 967-971.
5 Furtoryan T, Grand D. Postoperative wound
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6 Dettenkofer M, Wilson C, Ebner W, et al. Sur-
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outpatient effectiveness and efficiency. Man-
report.pdf (accessed Jan 2006).
8 Lathlean S. Skin cancer in general practice in
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Physician 1999; 28 (Suppl 1): S28-S31.
9 Del Mar CB, Lowe JB. The skin cancer workload
in Australian general practice. Aust Fam Physi-
cian 1997; 26 (Suppl 1): S24-S27.
10 Marks R. Dermatology for the non-dermatolo-
gist. Med J Aust 1996; 164: 430.
11 O’Cathain A, Brazier J, Milner PC, Fall M. Cost
effectiveness of minor surgery in general prac-
tice: a prospective comparison with hospital
practice. Br J Gen Pract 1992; 42: 13-17.
12 Heal C, Buettner P, Raasch B, et al. ‘Can sutures
get wet?’ A randomised controlled trial of
wound management in general practice. BMJ
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13 Sylaidis P, Wood S, Murray DS. Postoperative
infection following clean facial surgery. Ann
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14 Nagachinta T, Stephens M, Reitz B, Polk BF.
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15 Bruce J, Russell EM, Mollison J, Krukowski ZH.
The quality of measurement of surgical wound
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atic review. J Hosp Infect 2001; 49: 99-108.
16 Britt H, Knox S, et al. General practice activity in
Australia 2000–2001. Sydney: University of Syd-
17 Australian Bureau of Statistics. Basic commu-
nity profile. CLIB 2001. 2001 Census of Popula-
tion and Housing. Canberra: ABS, 2001. (ABS
Cat. No. 2024.0.)
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033119.shtml (accessed Jul 2006).
19 Messingham MJ, Arpey CJ. Update on the use
of antibiotics in cutaneous surgery. Dermatol
Surg 2005; 31: 1068-1078.
20 Cho CY, Lo JS. Dressing the part. Dermatol Clin
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21 Platt R. Antibiotic prophylaxis in clean surgery:
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(Received 28 Feb 2006, accepted 18 Jul 2006)