Systematic Review and Meta-Analysis of Bariatric Surgery
for Pediatric Obesity
Jonathan R. Treadwell, PhD; Fang Sun, MD, PhD; Karen Schoelles, MD, SM
Ann Surg. 2008;248(5):763-776. ©2008 Lippincott Williams & Wilkins
Abstract and I ntroduction
Objective: The prevalence of morbid obesity has risen sharply in recent years, even among
pediatric patients. Bariatric surgery is used increasingly in an effort to induce weight loss,
improve medical comorbidities, enhance quality of life, and extend survival. We performed a
systematic review and meta-analysis of all published evidence pertaining specifically to bariatric
surgery in pediatric patients.
Methods: We systematically searched MEDLINE, EMBASE, 13 other databases, and article
bibliographies to identify relevant evidence. Included studies must have reported outcome data
for =3 patients aged =21, representing =50% of pediatric patients enrolled at that center. We
only included English language articles on currently performed procedures when data were
separated by procedure, and there was a minimum 1-year follow-up for weight and body mass
Results: Eight studies of laparoscopic adjustable gastric banding (LAGB) reported data on 352
patients (mean BMI 45.8); 6 studies of Roux-en-Y gastric bypass (RYGB) included 131 patients
(mean BMI 51.8); 5 studies of other surgical procedures included 158 patients (mean BMI 48.8).
Average patient age was 16.8 years (range, 9-21). Meta-analyses of BMI reductions at longest
follow-up indicated sustained and clinically significant BMI reductions for both LAGB and RYGB.
Comorbidity resolution was sparsely reported, but surgery did appear to resolve some medical
conditions including diabetes and hypertension. For LAGB, band slippage and micronutrient
deficiency were the most frequently reported complications, with sporadic cases of band
erosion, port/tube dysfunction, hiatal hernia, wound infection, and pouch dilation. For RYGB,
more severe complications have been documented, such as pulmonary embolism, shock,
intestinal obstruction, postoperative bleeding, staple line leak, and severe malnutrition.
Conclusions: Bariatric surgery in pediatric patients results in sustained and clinically significant
weight loss, but also has the potential for serious complications.
Obesity among pediatric patients has increased sharply in recent years. The percentage of
adolescents in the United States with a body mass index (BMI) above the 95th percentile for
age and sex (based on Centers for Disease Control and Prevention (CDC) growth charts)
nearly tripled between 1970 and 1999 (from 5% to 14%), and an analysis of 1999 to 2002 data
estimated this prevalence at 16%.
Many studies have demonstrated the health risks of obesity in pediatric populations.[3-14]
Becque determined that 35 of 36 (97%) obese adolescents had 4 or more serious
cardiovascular risk factors. (The factors under consideration were: (1) serum triglyceride >100
mg/dL; (2) HDL cholesterol below the 10th percentile for age and sex; (3) total cholesterol >200
mg/dL; (4) systolic BP above the 90th percentile for age and sex; (5) dystolic BP above the 90th
percentile for age and sex; (6) maximal oxygen consumption <24 mL/kg of body weight; and (7)
strong immediate family history of cardiovascular disease.) Weiss found that 97 of 195
severely obese adolescents (50%) met criteria for the metabolic syndrome, as compared with 0
of 20 nonobese adolescents. Rhodes studied 14 morbidly obese children and adolescents
and found that 5 of them (36%) had sleep apnea, which was associated with more
neurocognitive deficits (learning, memory). Additional risks of obesity among adolescents
include musculoskeletal problems, asthma, gastroesophageal reflux disease (GERD),
pseudotumor cerebri, gallstones, and menstrual abnormalities.[3,6,13]
Research has also demonstrated reduced quality of life and social marginalization among
obese pediatric patients.[16,17] Schwimmer surveyed the quality of life of 106 obese patients
aged 5 to 18 years and found an average score of only 67, as compared with 83 for nonobese
pediatric patients (on their pediatric quality of life scale, 100 indicated excellent quality of life,
and 0 indicated extremely poor quality of life). The impact of obesity was persistent for both
psychosocial health and physical health. In another study of over 90,000 adolescents in the
National Longitudinal Study of Adolescent Health, the authors measured the number of
friendship nominations received by other adolescents. This study defined a friendship
nomination as when the obese adolescent is cited by another adolescent as a friend. The
average was lower for overweight adolescents (3.4) than for nonoverweight adolescents (4.8).
Also, obese adolescents were more likely to receive zero friendship nominations (which was
true for 12% of overweight adolescents as compared with 7% of nonoverweight adolescents),
suggesting social marginalization.
Obese pediatric patients are more likely to become obese adults than their nonobese peers.[7,18-
20] In a review of 15 studies, Serdula estimated that 42% to 63% of obese school-age children
become obese adults; the comparative risk of becoming an obese adult was 4 to 6.5 times
higher for obese school-age children than nonobese school-age children. Power used data
from a 1958 birth cohort and found similar relative risks of adulthood obesity based on
adolescent obesity. Whitaker found that 23 of 30 patients (77%) who had been severely
obese at age 15 to 17 years were still obese as adults, and this same percentage (77%) was
observed in a study by Freedman that included 186 obese adolescents.
Obesity during adolescence has also been tied directly to health problems in adulthood.[7,20-22]
Power reviewed 5 pertinent studies and found correspondence between adolescent obesity
and adulthood all-cause mortality, coronary heart disease, atherosclerosis, colorectal cancer,
gout, arthritis, and menstrual problems. Also, Abraham found higher prevalence rates of 4
medical conditions (diabetes, atherosclerosis, hypertension, and cardiovascular disease)
among 19 adolescents whose weight was =120% of the average weight for age and height.
Treatments for obesity are intended to induce weight loss, improve medical comorbidities,
enhance quality of life, and (ultimately) extend survival. Nonsurgical treatments, including
dietary modification, physical activity, behavioral modification, and pharmacotherapy, have
turned in generally unsatisfactory results thus far. Studies have observed high dropout rates,
and among patients who remain in the studies, only modest weight loss is achieved. For
example, in 3 recent trials (Chanoine et al, Savoye et al, and Berkowitz et al) followed
obese pediatric patients for 1 year after initiation of treatment. Chanoine et al enrolled 357
pediatric patients in a group to receive orlistat, hypocaloric diet, exercise, and behavioral
modification, but only 232 of them (65%) completed 1-year follow-up, and their average BMI
loss was only 0.55 units (from a baseline BMI of 35.6). Similarly, Savoye et al observed 1-
year completion in only 71% (75/105) of patients assigned to a weight management program,
and the average 1-year BMI reduction was only 1.7 units (baseline BMI 35.9). Berkowitz et al
observed somewhat greater BMI reduction (3.2 units from a baseline of 37.5) among 33 of 43
patients (77%) who completed 1-year follow-up.
One invasive treatment option for severely obese pediatric patients is bariatric surgery. Its
overall use has increased dramatically in recent years, from approximately 13,000 operations in
1998 to approximately 121,000 operations in 2004 (these figures include adults). Patients
under age 18 years comprise about 0.1% to 1% of bariatric surgery patients.[27-29] The estimated
adolescent bariatric rate (per 100,000 population) in the United States increased from 0.7 in
2000 to 2.3 in 2003. A 2005 survey of bariatric surgeons in the United States found that 49%
of them had performed bariatric surgery on one or more adolescents in the previous year, 75%
were planning to perform adolescent bariatric surgery in the coming year, and 55% either had a
bariatric program with pediatric specialists or were creating one.
Among adults, bariatric surgery is typically reserved for those with a BMI = 40 kg/m2, or =35
kg/m2 in the presence of one or more medical comorbidities.[32-34] Some authors have proposed
more stringent BMI criteria for the pediatric population: BMI =50 kg/m2, or =40 kg/m2 in the
presence of one or more medical comorbidities.[35-37] Others have suggested that the adult BMI
criteria should apply equally to this population.[38-40] Additional suggested criteria prior to
adolescent bariatric surgery included the attainment of physical maturity, demonstrated
decisional capacity, and a supportive family environment.
A wide variety of surgical procedures have been used to treat obesity. The 2 most commonly
performed bariatric surgical procedures are laparoscopic adjustable gastric banding (LAGB) and
the Roux-en-Y (RYGB) gastric bypass. The LAGB is a purely restrictive procedure in which the
surgeon places a silicone band around the entire upper portion of the stomach, creating a tiny
pouch where food empties from the esophagus to the upper stomach. The RYGB restricts
intake through the creation of a small gastric pouch, and also reduces food absorption via
bypass of the proximal small intestine. Other bariatric surgical procedures include vertical
banded gastroplasty (VBG), biliopancreatic diversion (BPD), biliopancreatic diversion with
duodenal switch (BPD/DS), banded bypass (BB), and laparoscopic sleeve gastrectomy (LSG).
The health consequences of obesity in pediatric patients, considered together with the potential
for bariatric surgery to prevent or resolve these consequences, motivate the need for a
comprehensive summary of the relevant evidence. Consequently, we performed a systematic
review and meta-analysis of published studies of pediatric patients who have received bariatric
Experienced medical librarians searched 15 databases, including PubMed and EMBASE, for
relevant studies. We also examined the bibliographies from identified studies, reviews and gray
literature. The last search was conducted on December 31, 2007.
Article I nclusion Criteria
All patients must have been age =21 at the time of surgery. The study must have appeared as
an English language article in a peer-reviewed journal. The surgical procedure must have been
a procedure currently performed in the United States, and if more than 15% of patients in the
study had different bariatric procedures (eg, 50% RYGB and 50% LAGB), data must have been
separated by procedure. The study must have reported data on weight, BMI, comorbidity
resolution, quality of life, and/or survival. We only included data that were based on at least 3
patients who represented at least 50% of pediatric surgical patients. For weight or BMI data, we
only considered data at least one year after surgery, but there was no minimum follow-up for
other outcomes. For quality-of-life outcomes, the study must have measured quality of life
before and after surgery using a previously validated instrument. Data on any nonsurgical
control groups were included only if the patients receiving nonsurgical treatment were
sufficiently similar to surgical patients. If there were multiple reports from the same surgical
center, we avoided double-counting patients by including data and outcomes that were based
on the largest number of patients and still meeting the other inclusion criteria.
We used studies' reports of BMI as a key outcome. Body fat is more accurately measured using
hydrodensitometry or dual-energy x-ray absorptiometry (DXA), but these methods are highly
labor-intensive and costly. BMI, however, only requires measurements of height and weight.
Field et al (2003) found that among 596 children and adolescents, BMI explained 72% of the
variance in body fat (corresponding to a Pearson r correlation of 0.85). Furthermore, the CDC
have stated that BMI is a reliable indicator of body fatness in most children and teens. These
observations suggest that in pediatric patients, BMI is a reasonably accurate surrogate for body
fatness, thus we used BMI as an outcome measure.
Meta-analyses of the mean change in BMI were conducted using the random-effects method of
DerSimonian and Laird. Because patients had already undergone unsuccessful attempts at
weight loss prior to surgery, our first set of analyses assumed that patients would not have lost
weight without surgery. This assumption was tested in sensitivity analyses in which we
investigated alternative assumptions that, without surgery, patients would experience modest
weight loss (up to 3.2 BMI units, which was the BMI reduction in the nonsurgical study by
Berkowitz et al). We measured heterogeneity with the I2 statistic, with I2 = 50% defining
For weight loss, a clinically significant amount was defined as 7% of body weight, because
patients who lose this amount of weight have been shown by other researchers to yield
substantial reductions in medical comorbidities of obesity (eg, diabetes).[45,46]
For meta-analysis of before-after studies of change in BMI, the computation of an effect size
requires a patient-level correlation between presurgical BMIs and postsurgical BMIs. Five
studies reported such individual patient data, so we calculated the correlation for each of these
studies, and then performed a random-effects meta-analysis of these correlations. We then
used the summary correlation (0.60) as an imputed correlation in studies that had not provided
individual patient data. In subsequent robustness tests, we used the 95% confidence bounds of
this correlation (0.36 and 0.76) to determine sensitivity to the choice of correlation.
Other sensitivity analyses included the removal of one study at a time to determine whether the
conclusion was driven by any single study; cumulative meta-analysis to determine sensitivity to
publication date; assessment of the width of the confidence interval around a summary effect
size to determine the robustness of a quantitative estimate; and removal of studies with less
than 75% follow-up to determine sensitivity of conclusions to the inclusion of studies with 50%-
Rating the Strength of the Evidence
We evaluated the overall stability and strength of the evidence for weight loss and comorbidity
resolution after bariatric surgery using a formal rating system. The system incorporates the
quality, quantity, consistency, robustness of the evidence, as well as the magnitude of observed
effects. Quality refers to the degree of potential bias in the design or conduct of studies.
Quantity refers to the number of studies and the number of enrolled patients. Consistency
addresses the degree of agreement among the results of available studies. Robustness
involves the constancy of conclusions in the face of minor hypothetical alterations in the data.
Magnitude of effect concerns the quantitative amount of benefit that patients experience after
Our system employs decision points that collectively yield an overall category that describes the
strength of the evidence for a quantitative estimate and qualitative conclusion as strong,
moderate, weak, or insufficient. The qualitative conclusion addresses the question, Does it
work? The quantitative estimate addresses the question, How well does it work? This distinction
allows flexibility in ratings of different aspects of the evidence. For example, an evidence base
can be considered weak in terms of the precise quantitative estimate of effect (eg, if estimates
vary widely among studies), but strong or moderate with respect to the qualitative conclusion
(eg, if all studies nevertheless demonstrate the same direction of effect).
To rate the quality of case series of bariatric surgery, we considered 6 criteria: (1) whether the
study was prospective; (2) whether the study had included consecutive patients; (3) whether the
outcome assessment was performed by an independent party; (4) whether the study was not
funded by a financially interested party; (5) whether the outcome was objective; and (6) whether
the data for the outcome contained at least 85% of the pertinent included patients. We
assessed the quality of a given study separately for the different outcomes and timepoints
reported by that study, because some criteria (eg, 85% completion) can vary by outcome or
I ncluded Studies
The study identification process is depicted in Figure 1. Of the 18 unique studies that met the
inclusion criteria, 8 investigated laparoscopic adjustable gastric banding (LAGB), 5 investigated
RYGB, one investigated both RYGB and vertical banded gastroplasty (VBG), 2 VBG only, one
BPD only, and one the banded bypass (BB) procedure. The total patient enrollment was 641;
the procedure-specific totals were 352 for LAGB, 131 for RYGB, 71 for VBG, 68 for BPD, and
19 for BB.
Study attrition diagram depicts article counts at each stage of the review process.
Key characteristics about enrolled patients and the procedures performed are listed in Table 1 .
For LAGB, the earliest procedures on pediatric patients were performed in 1996; 6 of the 8
LAGB studies used the LAP-BAND® (Inamed Health, Santa Barbara, CA) one used the
Swedish Adjustable Gastric Band (SAGB; Ethicon Endo-Surgery, Cincinnati, OH), and one used
the SAGB in 74% of patients and the LAP-BAND® in the remaining 26%. In the United States,
the LAP-BAND is F.D.A.-approved only in adults (although a trial in adolescents is ongoing); the
SAGB is still in the FDA approval process. The mean age ranged from 15.6 to 18 (weighted
average 16.7; overall age range 9-20). The percentage of females ranged from 50% to 81%
(weighted average 70%). The mean baseline BMI ranged from 42.4 to 50.5 (weighted average
46; overall BMI range 31-76.6).
For RYGB, the earliest procedures on pediatric patients were performed in the 1970s. Of the 6
RYGB studies, 2 used a laparoscopic approach, 3 used an open approach, and one used an
open approach for 94% of procedures and a laparoscopic approach for the remaining 6%. The
mean age ranged from 15.7 to 17.57 (weighted average 16.8; overall age range 11-21). The
percentage female ranged from 57% to 79% (weighted average 66%). The mean baseline BMI
ranged from 47 to 56.5 (weighted average 51.8; overall BMI range 38-95.5). All other
procedures were performed using an open approach; the patients undergoing these procedures
were similar to those undergoing LAGB or RYGB.
Fourteen of 18 studies explicitly stated that, prior to surgery, nonsurgical methods of weight loss
had been attempted and were unsuccessful in all patients. Eleven of 18 studies were conducted
in the USA; the other 7 were conducted in Israel (two studies), Italy (two studies), Australia,
Austria, or Saudi Arabia. Six non-USA studies investigated LAGB, and the seventh investigated
BPD. Fourteen studies reported data from a single surgical center, whereas the other 4 were
from 2 or more surgical centers.
One of the 18 studies reported a control group of patients who were not treated with bariatric
surgery (the Lawson study of RYGB). This control group included 12 patients who had
completed one year in a nonsurgical pediatric weight management program. However, patients
in the control group were much different from those who received surgery. Specifically, the
control group patients weighed statistically significantly less at baseline (mean BMI 47) than
surgical patients (mean BMI 56.5), and the study did not report any medical comorbidities
among control group patients, as compared with surgical patients who had several
comorbidities at baseline. These factors mean that the groups were not well-matched at
baseline, consequently we excluded the data from this control group, and included only the data
from the surgical group. Thus, for the purpose of our review, the studies were all case series.
Only one study was clearly conducted prospectively (the Nadler study). Retrospective design
may introduce bias because at the point when authors decide to publish the data, they are
armed with the knowledge of the favorable (or unfavorable) outcomes experienced by patients.
One strategy to counteract this potential bias is to include all eligible patients consecutively.
This was performed in 14 studies, not performed in 3 studies, and unclear in the remaining
study. Consecutive inclusions helps reduce selection for favorable outcomes. A related quality
factor is study completion rate: studies would ideally report long-term outcome data on all
patients who received the treatment. However, with any long-term follow-up, there will be
patients whose outcomes are not known or patients who have not reached longer timepoints.
Usually it is unclear whether dropouts experienced similar outcomes as those remaining in the
study, or whether recently-treated patients will eventually experience similar outcomes.
Patient weight is easily measured objectively, and of the 13 studies included for BMI data, 9
stated that patients attended follow-up visits in the clinic, suggesting that the weight data were
based on actual weight measurement rather than patients' self-reporting. Three other studies
did not report sufficient information on how the weight data were measured, and the other study
(the study by Greenstein and Rabner) based weight data on patient self-reporting. Two other
quality criteria that we applied involved the independence of outcome assessors and the study
funding source. None of the 18 studies used independent outcome assessment (eg, weights
recorded at a center independent from the surgeon and surgical staff), which raises the
possibility of outcome recording bias. Also, only one of the 18 studies reported the study funding
source. However, studies were generally conducted by bariatric surgeons, who do have
financial interest in the performance of surgery.
In the Results sections below, we discuss the outcome data that met the inclusion criteria,
separately for different bariatric procedures. This separation is important because different
bariatric procedures would be expected to result in different amounts of weight loss, different
rates of comorbidity resolution, and different types of complications.
Results of Adjustable Gastric Banding
Reduction in BMI. Of the 8 studies, 2 studies' data did not meet inclusion criteria for this
outcome because authors either did not report the number of patients followed for 1+ years (Al-
Qahtani et al), or did not report 1+ year data for at least 50% of patients (Nadler et al),
Thus, our BMI inclusion criteria were met by 6 of the 8 LAGB studies.
We conducted a meta-analysis of BMI change at longest follow-up after LAGB (top half of Fig.
2). The length of follow-up in the 5 studies ranged from 1 to 3 years, and the percentage of
surgical patients who were included in each study ranged from 58% to 100%. Our meta-
analysis indicated substantial heterogeneity (I2=56%). Given the imputation of a prepost
correlation for 4 of the 6 studies (Dillard et al, Yitzhak et al, Silberhumer et al, and
Angrisani et al) we did not attempt to explain this heterogeneity via meta-regression. The 95%
confidence interval of the random-effects summary statistic ranged from -13.7 to -10.6 BMI
units, indicating substantial weight loss after adjustable gastric banding. This interval compares
favorably to the minimum weight loss considered clinically significant (the dashed line in the
figure at 3.4 BMI units, which corresponds to 7% of body weight in these LAGB patients). The
finding of clinically significant weight loss after bariatric surgery persisted through all of our
sensitivity analyses, indicating a robust finding for BMI reduction at longest follow-up.
Meta-analyses of BMI reduction at longest follow-up after bariatric surgery. Forest plots of
random-effects meta-analyses of the change in BMI at longest follow-up, separately for
laparoscopic adjustable gastric banding (top half) and Roux-en-Y gastric bypass (bottom half).
The data for Fielding et al and Collins et al are based on earlier publications from those
centers (Dolan et al and Stanford et al, respectively) because the more recent publications
did not report data on at least 50% of patients at one year or longer.
Resolution of Comorbidities
Four of the 8 LAGB studies reported comorbidity data that met inclusion criteria. The pertinent
data on comorbidity resolution after LAGB appear in the upper section of Table 2 . The mean
length of follow-up in these 4 studies ranged from 1.3 to 2.9 years. For diabetes, 2 studies[50,53]
reported resolution rates of 100% (7/7) and 80% (4/5). For hypertension, 3 studies[50,52,53]
reported resolution rates of 50% (6/12), 100% (6/6), and 100% (3/3). For other comorbidities, no
more than one study reported resolution rates.
All 8 LAGB studies were included for complications data ( Table 3 ). No in-hospital or
postoperative death was reported in any LAGB study. Reoperations were performed on 8% of
the patients (28/352) to correct various complications such as band slippage, gastric dilation,
intragastric band migration, psychologic intolerance of band, hiatal hernia, cholecystitis, and
tubing crack. Overall, band slippage was the most frequently reported specific complication
(3%; 12/352). Eight of the 12 cases occurred in one center using SAGB, while the other 4 cases
occurred in 3 centers using LAP-BAND. In addition, 8 cases of iron deficiency and 5 cases of
mild hair loss were reported; the remaining reported complications had a case number equal to
or less than three. No studies reported data on the impact of surgery on growth or development.
Results of Roux -en-Y Gastric Bypass
Reduction in BMI. Of the 6 studies, 1 (Barnett et al) did not meet inclusion criteria for this
outcome because authors did not report the length of follow-up of patients receiving specific
procedures. Another study (Rand et al) was excluded from consideration because it was very
low quality because of nonconsecutive patient inclusion and the possibility that BMI data were
based on patient recall rather than objective weight measurement. Thus, our BMI inclusion
criteria were met by 4 of the 6 RYGB studies.
As with LAGB, we conducted a meta-analysis of BMI change at longest follow-up after RYGB
(bottom half of Fig. 2). The mean length of follow-up in the 4 studies ranged from 1.0 years to
6.3 years, and the percentage of surgical patients who were included in each study ranged from
61% to 90%. Our meta-analysis indicated no heterogeneity (I2=0%). The 95% confidence
interval of the random-effects summary statistic ranged from -17.8 to -22.3 BMI units, indicating
substantial weight loss after Roux-en-Y gastric bypass. As with LAGB, this interval compares
favorably to the minimum weight loss considered clinically significant (the dashed line in the
figure at 4.1 BMI units, which corresponds to 7% of body weight in these RYGB patients). The
finding of weight loss after bariatric surgery persisted through all of our sensitivity analyses,
indicating a robust finding for BMI reduction at longest follow-up.
Resolution of Comorbidities
Four of 6 RYGB studies reported comorbidity data that met inclusion criteria. The included data
appear in the middle section of Table 2 . Among these 4 studies, the mean length of follow-up
ranged from 5 months to 2.7 years. For hypertension, 3 studies[27,28,60] reported resolution rates
of 50% (3/6), 82% (9/11), and 100% (3/3). For sleep apnea, 2 studies[27,62] each reported
resolution rates of 100% (6/6 and 10/10). For other comorbidities, no more than one study
reported resolution rates.
All 6 RYGB studies were included for complications data ( Table 3 ). No in-hospital death was
reported. One patient in the Lawson et al study.[62-64] died 9 months after surgery, because of
severe Clostridium difficile colitis, severe diarrhea, an extended period of profound
hypovolemia, and multiple organ failure. Three additional patients died of causes that were
unlikely to be directly related to the bariatric surgeries (one patient in the Barnett study died 4
years after surgery; 2 patients in the Sugerman et al study died 2 years and 6 years after
Reported postoperative complications of RYGB included some potentially life-threatening
conditions such as shock, pulmonary embolism, severe malnutrition, immediate postoperative
bleeding, and gastrointestinal obstruction. The most frequently reported type of complication
involved protein-calorie malnutrition and micronutrient deficiency. Inconsistencies in reporting
precluded calculation of an overall reoperation rate after RYGB.
Regarding physical maturation, Rand et al reported patients' preoperative and postoperative
heights and concluded that there was no evidence of growth retardation after surgery (at an
average follow-up of 6 years). However, the authors of the study also stated that the question
as to whether these adolescents achieved their expected growth could not be extracted from
Results of Other Procedures
For weight or BMI data, three[68,69,71] of the 5 studies of other procedures met the inclusion
criteria, however, all 3 of these studies were of very low quality. Unique quality problems with
these 3 studies involved nonconsecutive patient inclusion in 2 of the 3 studies; weights based
on patient reporting or unreported method of obtaining weight data; and <85% completion in 2
of the 3 studies.
For comorbidity resolution, 3 of the 5 studies reported data, but Barnett et al only reported
data combined across procedures, and Greenstein and Rabner included no more than 2
patients for any given comorbidity, therefore these data did not meet inclusion criteria. The
reported comorbidity results of the BPD study appear at the bottom of Table 2 .
The complications data appear in the lower sections of Table 3 . No in-hospital deaths were
reported, and 3 follow-up deaths were reported (all after BPD; the causes were protein
malnutrition, pulmonary edema, and acute necrotizing pancreatitis). In the VBG studies,
recurrent gastric ulceration (in 2 patients), enlarged pouches (in 2 patients) and staple line
disruption (in one patient) were reported. The study of BPD (a malabsorptive procedure)
reported 11 cases of protein malnutrition. In the banded bypass study, 2 revisions for gastro-
gastric fistula, one cholecystectomy, one recurrent marginal ulcer requiring antacids, and 3
plastic surgeries for excess skin were reported as postsurgery complications. None of the 5
studies reported any data on the potential impact of physical growth.
Strength of Evidence
Our strength-of-evidence ratings for each outcome of each bariatric procedure are shown in
Table 4 . The strength ratings reflect a balance of various factors including low/moderate
quality, limited quantity (especially for comorbidity resolution), large magnitude of reported
effects, and consistency of results across studies. We did not draw precise quantitative
conclusions for any outcomes because of the imputation of prepost correlations (for BMI data)
or limited numbers of studies (comorbidity resolution).
In considering bariatric surgery for pediatric patients, 3 unique issues arise: informed consent,
interference with physical growth/maturation, and compliance with postsurgical diets.
Regarding informed consent, Inge et al(2004) stated that one important ethical consideration
is whether the pediatric patient has decisional capacity. Determining decisional capacity often
requires consultation with the family, and patients without such capacity should not be treated
surgically. Even with good decisional capacity when surgery is elected, some pediatric bariatric
patients may later regret the decision to undergo surgery. If so, bariatric procedures that are
more easily reversed (such as LAGB) may receive greater consideration in the pediatric
Another concern is the potential for bariatric surgery to interfere with physical growth and/or
sexual maturation. In our review, only one study formally evaluated the growth of patients after
surgery, and the authors considered the data inconclusive. We note that the overall average
age of patients in the included studies was 16.7, and our analysis of CDC growth charts
suggests that an average boy of this age has completed 98.4% of his growth to age 20, and the
corresponding percentage for a girl is 99.6%. These percentages suggest that, among the
pediatric patients who have received bariatric surgery, the impact of surgery on height is largely
moot. The impact on other aspects of maturation, however, is unclear.
Compared with adults, pediatric patients may have lower levels of compliance with postsurgical
dietary regimens, dietary supplements, and exercise recommendations. One study included in
our review reported that only 13% of pediatric patients continued taking nutritional supplements
as instructed. No other included studies examined the issue. To adequately address concerns
about low compliance, additional evidence is needed from future studies.
Turning to surgical outcomes, the amount of weight loss after bariatric surgery among pediatric
patients appears to be clinically significant. The F.D.A. defines clinically significant weight loss
for pharmacotherapy as 5% of body weight. Trials in diabetes prevention in obese patients
have targeted 7% of body weight as a meaningful weight loss goal.[45,46] In a pediatric patient of
average age, height and BMI in the included studies, the 5% and 7% goals correspond to BMI
reductions of only 2.7 and 3.7 units, respectively. Our meta-analyses of BMI reductions (Fig. 1)
show that postsurgical weight loss far exceeds these targets. The BMI reduction appears to be
larger after RYGBP than after LAGB, however the RYGBP patients had larger presurgical BMIs
(~52 versus~46), and some of the weight loss difference may be because of the baseline
A more direct measure of clinical impact, however, is the postsurgical status of obesity-
associated comorbidities. In the pediatric population, some studies have reported the
postsurgical resolution of comorbidities such as diabetes and hypertension. This evidence,
however, is sparsely reported. Future decisions about bariatric surgery in this population will be
aided by improved reporting of key adolescent health outcomes including comorbidities, bone
growth, postsurgical compliance, and physical and sexual maturation. We also found limited
evidence on quality-of-life improvements after surgery (only one study's data met the inclusion
criteria), and no studies of pediatric patients have followed patients long enough to determine
whether bariatric surgery extends survival. Two recent studies suggested that, among obese
adults, those who chose bariatric surgery lived longer than those who did not.[73,74]
The applicability of that finding to pediatric patients is unclear. Two LAGB studies have directly
compared the postsurgical outcomes of adolescents and adults (these adolescents were
included in our meta-analysis of BMI reduction after LAGB).[48,58] In a study by Dolan, 2 years
after LAGB, the mean BMI for the 17 adolescents (median age 17; range 12-19) had dropped
from 42.2 to 30.1, whereas for the 17 matched adults (median age 41; range 23-70) it had
dropped from 41.8 to 33.1. Similarly, Dillard et al (2007) reported similar weight loss between
adolescents and adults. These findings suggest that the BMI impact of surgery does not depend
on age, but additional research is necessary to permit firm conclusions.
The Teen Longitudinal Assessment of Bariatric Surgery(Teen-LABS) is an ongoing four-center
study devoted to prospective examination of the outcomes of pediatric bariatric surgery. The
plan is to enroll 200 patients, all aged 19 or less, and examine outcomes after bariatric surgery
(mostly RYGB between 2007-2009) (see http://www.cincinnatichildrens.org/teen-LABS for
details). Outcomes to be collected include not only weight loss but medical comorbidities, early
(30 days) and late (1-2 years) complications, and psychosocial status (eating behavior,
depressive symptoms, and health-related quality of life). Also, researchers will compare these
results to the surgical outcomes of 200 adults who had a history of severe obesity before the
age of 18 but did not receive surgery at that time. This comparison may shed light on the health
implications of postponing surgery.
In general, pediatric patients who undergo bariatric surgery have previously had unsuccessful
weight loss with nonsurgical methods. The included studies, however, did not provide details
about which methods were attempted, the intensity of those methods, the duration of attempted
treatment, or the success criteria. The United Kingdom National Institute for Clinical Excellence
(NICE) published a systematic review in December 2006 of obesity treatments, including
nonsurgical weight loss treatments in pediatric patients. The trials reviewed, however, do not
shed light on the anticipated efficacy of nonsurgical methods in patients who qualify for bariatric
surgery. Those trials generally involved patients who were younger and less obese (eg, BMI
~30, age ~12 as opposed to BMI ~50 and age ~17), and some studies followed patients for only
a short period of time (eg, 9 months). The single trial in our review that compared surgical to
nonsurgical approaches did not include patient groups of comparable weight (and probably not
of comparable comorbidity burden).
The NICE review was one of 5 other systematic reviews addressing the use of bariatric surgery
for pediatric patients, all published between 2003 and 2006.[76-80] Of the 27 included articles in
our review, 13 were not included by any of the other reviews, mostly because of later
publication dates. Eight other publications were included by other reviews but not ours. We
excluded these either because the bariatric procedure was outdated;[81-85] because authors
combined data on different procedures; because it was a case study; or because it focused
on a single adverse event.
In the absence of randomized controlled studies, decision makers - including clinicians, patients
and policy makers - are forced to make choices based on the information that is currently
available. In the interest of making nonrandomized surgical studies more useful for this purpose,
we encourage improvements in the reporting of data collection, patient follow-up and outcomes.
Elapsed follow-up times for study patients vary over a wide range as do time points chosen for
evaluation. Overlap of patient populations in subsequent publications documenting longer
follow-up and/or additional patient experience may not always be readily apparent. Right-
censoring (ie, patients with more recently performed surgery) is often not distinguished from
loss to follow-up. Slim et al (2003) have developed and validated a quality assessment tool for
surgical publications which merits consideration by authors in this field. Table 5 lists several
items in the instrument that seem particularly relevant to the bariatric surgery literature.
We believe that the present review contributes to the literature in several ways. First, we
included 13 publications not previously available. Second, we rated the strength of the evidence
using a rating system to incorporate the quality, quantity and consistency of the evidence. Third,
we performed meta-analyses to estimate the overall impact on BMI, separately for different
procedures. Fourth, we considered the clinical significance of BMI changes by comparison to
established targets. Finally, we performed multiple sensitivity analyses to show that the
conclusions about weight loss do not depend critically on analytic assumptions. The limitations
of our review reflect the lack of reporting of long-term data on a sufficient number of
participants, of comorbidity burden and resolution, and of compliance with postsurgical
recommendations. Future studies of bariatric surgery in obese pediatric patients should make
an effort to capture and report this important information.
Table 1. I ncluded Studies
Table 2. Resolution of Medical Comorbidities After
Table 3. Complications of Bariatric Surgery