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Table 5: Complications and body mass index group
Underweight
and normal Overweight Class I Class II Class III P-value Sub-analysis
n % n % n % n % n %
Overall 951 2,011 1,708 830 516
Any complication 42 4.4 115 5.7 105 6.1 53 6.4 63 12.2 < 0.0001 dgij
Surgical complication 14 1.5 33 1.6 20 1.2 16 1.9 17 3.3 0.0214 dgi
Wound complication 27 2.8 79 3.9 81 4.7 40 4.8 48 9.3 < 0.0001 bcdgij
Medical complication 3 0.3 11 0.5 9 0.5 7 0.8 8 1.6 0.0739
Return to operating room 14 1.5 33 1.6 19 1.1 16 1.9 17 3.3 0.0156 dgi
Superficial SSI 26 2.7 56 2.8 62 3.6 27 3.3 37 7.2 < 0.0001 dgij
Deep SSI 0 0.0 15 0.7 8 0.5 5 0.6 1 0.2 NR
Organ/space SSI 0 0.0 0 0.0 2 0.1 2 0.2 0 0 NR
Wound dehiscence 1 0.1 8 0.4 13 0.8 6 0.7 14 2.7 < 0.0001 bdgij
Venous
thromboembolism 2 0.2 2 0.1 2 0.1 2 0.2 0 0 NR
Unplanned reintubation 0 0.0 1 0.1 0 0 0 0 1 0.2 NR
Urinary tract infection 0 0.0 3 0.1 1 0.1 3 0.4 1 0.2 NR
Other bleeding 1 0.1 3 0.1 6 0.4 1 0.1 4 0.8 0.1024
Hospital length of stay,
median and range 0 0-234 0 0-31 0 0-32 1 0-6 1 0-15 < 0.0001 bcdefghij
P-value subanalysis key: P-value < 0.05 in a (underweight and normal vs. overweight), b (underweight and normal vs. class I), c (underweight and
normal vs. class II), d (underweight and normal vs. class III), e (overweight vs. class I), f (overweight vs. class II), g (overweight vs. class III), h (class I vs.
class II), i (class I vs. class III), j (class II vs. class III). P-values are not reported (NR) for any variables with a cell size of 0. SSI: surgical site infection

propensity score matched to control for preoperative performed for those preoperative and intraoperative
and intraoperative variables, in order to isolate the variables with n > 10 events, and P < 0.05 on bivariate
effect of obesity on postoperative outcomes. Patient screen.
characteristics were matched if n > 10 (i.e., greater than
10 events) and P < 0.05 on bivariate screen. Based on Data were then separated into two groups: patients
these criteria, matched characteristics included the who were obese (BMI of 30 or more) and patients who
following: age; diabetes mellitus; active smoking; alcohol were not obese (BMI below 30). Patients were matched
use; hypertension; respiratory disease; heart disease; on a 1:1 basis using propensity scores from a logistic
history of transient ischemic attack or stroke; bleeding regression model (as described above). Outcomes were
comorbidity; preoperative wound infection; steroid or then compared between the matched cohorts using
immunosuppressant use; recent weight loss > 10% of McNemar’s test and the Wilcoxon signed rank test.
total body weight in 6 months prior to surgery; total Statistical significance is indicated by P < 0.05.
number of comorbidities (none, one, or two or more);
American Society of Anesthesiologists (ASA) class; RESULTS
inpatient versus outpatient status; operative time; and
total work relative value units. Overall
Between 2005 and 2013, the NSQIP datasets identified a
Statistical analysis total of 6,016 patients who underwent primary reduction
Characteristics of the sample were summarized using mammaplasty with 30-day postoperative follow-up. The
descriptive statistics. Medians and ranges were reported patients were predominantly white, comprising 46.1%
for continuous variables; frequencies and percentages are of the cohort, and 15.3% were black. Fifty percent were
reported for categorical variables. The chi square test, younger than 45 years of age, 44.3% were between 45
Fisher’s exact test and the Kruskal-Wallis test were used to and 65 years, and only 5.7% were older than 65 years.
determine association between BMI groups and various
demographic, comorbidity and outcome variables. If a From the total group of patients, 28.7% had at least one
statistically significant association was detected between preoperative comorbidity, and 9.5% had two or more.
a BMI group and a variable, a subgroup analysis was Common comorbidities included hypertension (21.7%),
performed using the same tests to determine which of active smoking (11.2%), and diabetes (4.7%) [Table 1].
the groups were significantly different from each other. Other factors to assess preoperative risk included ASA
Multivariable analysis of postoperative outcomes was classification, with 28.0% in class 1, 60.4% in class 2, 11.4%
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