Surgical Science, 2013, 4, 8-12
Published Online December 2013 (http://www.scirp.org/journal/ss)
http://dx.doi.org/10.4236/ss.2013.412A002
Open Access SS
Amelioration of Diabetes Mellitus Type II after Sleeve
Gastrectomy—Data on Nationwide Survey on Quality
Assurance in Bariatric Surgery in Germany*
I. El-Sayes1, R. Weiner1, M. Talai Rad2, S. Wolff3, C. Knoll4, T. Manger5,6, C. Stroh5,6,7#
1Sachsenhausen Hospital, Frankfurt, Germany
2Helios Hospital, Bad Saarow, Germany
3Department of General, Abdominal and Vascular Surgery, University Hospital Magdeburg, Magdeburg, Germany
4Stat Consult, Magdeburg, Germany
5Department of General, Abdominal and Paediatric Surgery, SRH Hospital, Gera, Germany
6Institute of Quality Assurance in Surgery gGmbH, University Magdeburg, Magdeburg, Germany
7Competence Network Obesity, Germany
Received August 19, 2013; revised September 17, 2013; accepted September 25, 2013
Copyright © 2013 I. El-Sayes et al. This is an open access article distributed under the Creative Commons Attribution License,
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
ABSTRACT
Introduction: Sleeve Gastrectomy (SG) is becoming more popular due to its weight reducing effect and promising
anti-diabetic efficacy. However, long term results are still lacking. Methods: The study focuses on anti-diabetic effi-
cacy of SG through retrospective analysis of data for patients who underwent SG in Germany from 2005 to 2011.
Anti-diabetic efficacy was assessed at 1, 2 and up to 4 years after surgery. Results: 5400 morbidly obese patients un-
derwent SG. Of these 5400 patients 13.2% (n = 712) were insulin treated (IT) and 21.6% (n = 1165) were non-insulin
treated (NIT). Total follow-up was accomplished in 41.24% of patients. Percentage of remission and improvement (RI)
at 1 year was 83.8% (80.2% for insulin treated (IT) vs. 85.1% for non-insulin treated (NIT)). RI% at 2 years dropped to
77.6% (76.9% for IT vs. 77.9% for NIT patients). With late follow up (up to 4 years), RI% was 65.9% (58.8% for IT vs.
66.7% for NIT patients). Difference between IT and NIT patients was insignificant. Conclusion: SG shows promising
ant-diabetic efficacy at 1 year, 2 years and up to 4 years after surgery. This efficacy gradually drops with prolonged
time interval after surgery and seems to be insignificantly higher among NIT vs. IT patients.
Keywords: Sleeve Gastrectomy; Diabetes Mellitus Type II; Diabetes Remission; Metabolic Surgery
1. Introduction
Sleeve Gastrectomy (SG) was initially described as the
first step of biliopancreatic diversion with duodenal
switch in super obese patients [1]. Recently, stand-alone
SG is gaining worldwide popularity, being a relatively
non-technically demanding procedure with excellent re-
sults, in terms of substantial weight loss. Accordingly,
SG is now approved as a definitive treatment in patients
with a body mass index (BMI) >40 kg/m2 or BMI >35
kg/m2 in diabetic patients [2-4]. This is due to the fact
that SG has an extended spectrum of action which covers
additional satisfactory improvement of diabetic state [2-
4]. It has also been proposed with encouraging results for
diabetic non-morbidly obese patients with optimistic
outcome [2-4]. Being a relatively recent technique, long
term effect of SG is currently under research. This na-
tionwide survey demonstrates long term anti-diabetic ef-
ficacy of SG in morbidly obese Germans who underwent
SG from 2005 to 2011.
2. Patients and Methods
*Conflict of interest: German Bariatric Surgery Registry is supported
by BMBF with No. 01GI1124.
The corresponding author confirms no links to these firms. The topic is
p
resented in an independent light and the information outlined is pro-
duct neutral.
#Corresponding author.
Patient selection: This data pool includes morbidly obese
Germans who underwent SG between 2005 and 2011 in
107 hospitals cooperating with the German Bariatric Sur-
gery Registry (GBSR), Institute of Quality Assurance in

I. EL-SAYES ET AL. 9
Surgery at the Otto-von-Guericke University of Magde-
burg [5]. Data were collected in a prospective manner.
That is to say, every year a new sample of population is
added to the already existing cohort. After complete data
collection, retrospective statistical analysis was done.
Inclusion criteria conformed to the National Institutes of
Health Consensus criteria [6]. The term (diabetes) refers
to a clinical status with a fasting plasma glucose level of
more than 126 mg/dl [7].
Assessment of diabetic profile was done at 1, 2 and up
to 4 years after SG. Accordingly, patients fell into one of
four presentations, namely: remission, improvement, no
change and deterioration. Remission, which can be either
partial (improvement) or complete, was defined as
achieving glycaemia below the diabetic range (126 mg/dl)
in the absence of active pharmacologic (anti-hypergly-
cemic medications, immunosuppressive medications) or
surgical (ongoing procedures such as repeated replace-
ments of endoluminal devices) therapy [8].
3. Statistical Analysis of Data
Statistical analysis was performed by Stat Consult GmbH
using SAS 9.2 software program. Descriptive statistical
analysis was specified by presentation of absolute and
relative frequencies for nominal values and mean, stan-
dard deviation, minimum and maximum values for con-
tinuous variables. Median was considered for high varia-
tion. Descriptive statistics were extended by frequency
tests for several values and variables. For further verifi-
cation of the differences between the variables χ2-test
was used. Significant differences are shown if p < 0.05.
Continuous variables of two groups were compared with
two sample t-Test.
4. Results
The study included 5400 morbidly obese patients who
underwent SG from 2005 through 2011. Their demo-
graphic data are demonstrated in Table 1. Of these 5400
patients who underwent SG 13.2% were insulin treated
(IT) vs. 21.6% who were non-insulin treated (NIT). All
these patients suffered on diabetes mellitus type II. Fol-
low up was successfully accomplished in 34.7% patients
after one year, 10.4% at two years and for 3.4% for pa-
tients up to 4 years. Those represent our cohort. This
relatively low follow up rate is due to the fact that follow
up program is not covered by the health insurance system
in Germany.
Patients are divided in two major groups according to
the anti-diabetic efficacy of SG: patients who show either
remission or improvement of their diabetic status (RI)
and those who show either no change of their diabetic
status or deterioration (ND). Remission was defined of
total loose of diabetes mellitus type II independent if the
patient was treated with insulin or oral anti-diabetics.
Several categories were defined patients could have a
reduction of insulin dose at all, a reduction of the oral
doses as well as a change from insulin to non-insulin
treated diabetes type II. Also some patients developed
diabetes in spite of weight reduction in case of better
medical examinations. Table 2 illustrates all these changes
as well as RI% among patients (total, IT and NIT) after
SG at 1, 2 and up to 4 years (Table 3 ). RI% was higher,
but statistically insignificant among NIT vs. IT patients
at all follow up points.
Data on duration of diabetes prior to surgery were not
available for these patients.
5. Discussion
Weight gain has always been referred to as a risk factor
for impaired glucose tolerance. Moreover, anti-diabetic
agents are usually associated with weight gain [9]. This
twin association of diabetes and obesity was the corner
stone for many studies centered upon simultaneous con-
trol of both metabolic disorders. Conservative methods
proved to lack long-lasting efficacy [10]. Surgery seems
therefore to be the most suitable alternative [10].
Among variable surgical options, SG has recently
emerged as a possible remedy for both diabetes and obe-
sity. Anti-diabetic effect of SG has even been proved to
precede its weight reducing effect [11]. Being a relatively
recent procedure, proper explanation of its mechanism of
action is currently under research. It is suggested that SG
is not simply an absolute restrictive maneuver. Fundus
Table 1. Demographic data of morbidly obese diabetics who
underwent SG in Germany from 2005 through 2011 and
incidence of associated co-morbidities.
 Gender:
 Males 1965 (36.4%)
 Females 3435 (63.6%)
 Mean age in years: 43.6
 Males 44.7
 females 42.9
 Mean BMI in kg/m²: 52.1
 Males 53.2
 Females 51.5
 Percentage of patients with
associated co-morbidities
(other than diabetes mellitus): 89.7%
 Hypertension 65.9%
 Skeletal diseases 49.8%
 Sleep apnea 26.9%
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I. EL-SAYES ET AL.
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Table 2. Changes of diabetes mellitus type II at 1, 2 and up to 4 years after SG for IT, NIT patients and for the total cohort.
At least one follow-up At one year (0.5 - 1.5 years)A t two years (1.5 - 2.5 years) Up to four years (>2.5 years)
N (%) N (%) N (%) N (%)
Patients with follow-up 2227 (41.2%) 1873 (34.7%) 559 (10.4%) 131 (2.4%)
After one year After two years Up to four years
(%) BMI (kg/m2) (%) BMI (kg/m2) (%) BMI (kg/m2)
Reduction of insulin
IT patients 40.9 (n = 99)−12.95 (±5.24) 39.7 (n = 31) −15.76 (±6.63) 17.7 (n = 3) −19.81 (±4.48)
Change from IT to NIT
IT to NIT patients 4.6 (n = 11)−13.80 (±3.70) 6.4 (n = 5) −16.93 (±6.85) - -
New onset of IT
IT patients 2.1 (n = 5) −7.65 (±10.75) 5.1 (n = 4) −12.50 (±5.60) - -
Reduction of oral anti-diabetics
NIT patients 34.8 (n = 152) −13.84 (±5.84) 18.0 (n = 22) −13.28 (±5.85) 22.2 (n = 6) −11.73 (±5.50)
Change from NIT to IT
NIT to IT patients 0.9 (n = 4) −11.00 (±3.68) 0.8 (n = 1) −5.93 (-) - -
New onset of NIT
NIT patients 0.7 (n = 3) −8.22 (±4.19) 0.8 (n = 1) −6.57 (-) 11.1 (n = 3) −13.88 (±6.88)
Remission and improvement (RI)
Total diabetics 83.8 −14.48 (±5.71) 77.6 −16.17 (±7.01) 65.9 −15.40 (±6.41)
IT patients 80.2 −14.15 (±5.96) 76.9 −16.03 (±6.51) 58.8 −20.18 (±6.72)
NIT patients 85.1 −14.63 (±5.62) 77.9 −16.19 (±7.35) 66.7 −11.95 (±4.98)
IT: insulin treated, NIT: non-insulin treated.
Table 3. Follow-up rate of patients at 1, 2 and up to 4 years after primary SG.
At least one follow-up At one year (0.75 - 1.25 years)At two years (1.75 - 2.25 years) Up to four years (>2.25 years)
N (%) N (%) N (%) N (%)
Patients with follow-up
2 227 (41.2%) 1 837 (34.7%) 599 (10.8%) 131 (2.4%)
IT: insulin treated, NIT: non-insulin treated.
resection, with resultant reduction of orixegenic ghrelin
hormone, results primarily in post-operative weight loss.
However, ghrelin hormone proved as well to have dia-
betogenic effect [12]. This together with rapid gastric
emptying, shorter bowel transit time and post-operative
rise of serum incretins (glucagon-like-peptide-1 and pep-
tide-YY) seem to augment its anti-diabetic effect [13,14].
These findings could partly explain the anti-diabetic ef-
fect of SG.
Although this potential to control diabetes seems to be
higher with RYGB if compared to SG [15,16], SG seems
however to have promisingresults. An efficacy of 88%
was observed in less than one year after SG in diabetic
patients [17]. This group of patients required only 6
months to achieve a mean HbA1C level of 6%. Our re-
sults go in accordance. Within one year after surgery,
83.8% of our patients had RI of their diabetic state.
Ruiz-Tovar et al. noticed that 83.3% of patients dis-
continued their hypoglycemic medications within one
month after SG. These findings were maintained for 24
months after surgery [18]. In this survey, a more or less
stationary RI% was noticed at midterm follow up inter-
vals of 2 years after SG, where RI% dropped slightly to
79.5%.
SG is the newest member among all obesity proce-
dures. Long-term efficacy of SG is therefore currently
lacking. However, some reports in literature studied the
anti-diabetic efficacy of SG five years after surgery and
attributed normalization of fasting blood sugar and
HbA1C encountered in 76.9% of their patients to SG

I. EL-SAYES ET AL. 11
[19]. We noticed that 65.9% of our patients maintained
their diabetes free state with long-term follow up interval
(up to 4 years). Abbatini et al. in analysis of long term ef-
fects of SG noticed an anti-diabetic efficacy, starting by
87.8% one year after surgery, gradually decreasing to
84.6% at two years and further dropped to 76.9% at five
post-operative years. Similarly our cohort showed that
83.8% of patients achieved RI within 1 year after SG.
This percentage dropped gradually to 77.6% at 2 years
and 65.9% up to 4years after operation respectively.
Reports about anti-diabetic efficacy of SG highlighted
a clinical situation of persisting diabetes after operation.
This could be encountered in type 1 insulin treated dia-
betics with autoimmune destruction of pancreatic beta
cells. It is therefore recommended to exclude this condi-
tion before surgery to optimize surgical outcome [20].
Schauer et al. similarly noticed an 87% reduction in the
number of patients requiring oral anti-diabetic medica-
tions after surgery vs. only 79% reduction among the
insulin requiring group [21]. In the same way, NIT pa-
tients in our cohort showed a higher RI% than IT at all
follow up intervals. This difference was statistically not
significant.
Although this report demonstrates in our opinion long
term outcome of a relatively recent surgical procedure,
which is lacking in most published studies, our database
lacks however accurate assessment of pre- and post-op-
erative HbA1C levels. This is a limitation in this survey.
Moreover, the follow up rate for our patients is relatively
low. However, this is attributed to the fact that follow up
of patients is not covered by health insurance service in
Germany.
6. Conclusion
In conclusion, SG is rapidly expanding in Germany, due
to its promising results in terms of post-operative weight
loss. Its anti-diabetic efficacy, even in IT patients, seems
also to play a role in its growing popularity. However,
long term assessment of its anti-diabetic efficacy is cur-
rently under evaluation.
7. Acknowledgements
We thank the following firms for financially supporting
the study: Johnson & Johnson MEDICAL GmbH, Ethi-
con Endo-Surgery Deutschland, Norderstedt Covidien Deu-
tschland GmbH, Neustadt/Donau Pharm-Allergan GmbH,
Ettlingen.
REFERENCES
[1] G. Almogy, P. F. Crookes and G. J. Anthone, “Longitu-
dinal Gastrectomy as a Treatment for the High-Risk Su-
per-Obese Patient,” Obesity Surgery, Vol. 14, No. 4, 2004,
pp. 492-497.
http://dx.doi.org/10.1381/096089204323013479
[2] M. Deitel, R. D. Crosby and M. Gagner, “The First Inter-
national Consensus Summit for Sleeve Gastrectomy (SG),
New York City, October 25-27, 2007,” Obesity Surgery,
Vol. 18, No. 5, 2008, pp. 487-496.
http://dx.doi.org/10.1007/s11695-008-9471-5
[3] M. Gagner, M. Deitel, T. L. Kalberer, et al., “The Second
International Consensus Summit for Sleeve Gastrectomy,
March 19-21, 2009,” Surgery for Obesity and Related
Diseases, Vol. 5, No. 4, 2009, pp. 476-485.
[4] M. Daskalakis and R. A. Weiner, “Sleeve Gastrectomy as
a Single-Stage Bariatric Operation: Indications and Limi-
tations,” Obesity Facts, Vol. 2, No. S1, 2009, pp. 8-10.
http://dx.doi.org/10.1159/000198239
[5] C. Stroh, R. Weiner, T. Horbach, K. Adipositas, A. Adi-
positaschirurgie, et al., “New Data on Quality Assurance
in Bariatric Surgery in Germany,” Zentralblatta fur Chi-
rurgie, Vol. 138, No. 2, 2013, pp. 180-188.
[6] “NIH Conference Gastrointestinal Surgery for Severe Obe-
sity. Consensus Development Conference Panel,” Annals
of Internal Medicine, Vol. 115, 1991, pp. 956-961.
[7] American Diabetes Association, “ADA Standards of Me-
dical Care in Diabetes—2009,” Diabetes Care, Vol. 32,
No. S1, 2009, pp. S13-S61.
[8] J. B. Buse, S. Caprio, W. T. Cefalu, et al., “How Do We
Define Cure of Diabetes?” Diabetes Care, Vol. 32, No.
11, 2009, pp. 2133-2135.
[9] F. X. Pi-Sunyer, “The Effects of Pharmacologic Agents
for T2DM on Body Weight,” Postgraduate Medicine, Vol.
120, 2008, pp. 5-17.
http://dx.doi.org/10.3810/pgm.2008.07.1785
[10] B. R. Smith, P. Schauer and N. T. Nguyen, “Surgical Ap-
proaches to the Treatment of Obesity: Bariatric Surgery,”
Endocrinology and Metabolism Clinics of North America,
Vol. 37, No. 4, 2008, pp. 943-964.
http://dx.doi.org/10.1016/j.ecl.2008.08.001
[11] J. S. Todkar, S. S. Shah, P. S. Shah and J. Gangwani,
“Long-Term Effects of Laparoscopic Sleeve Gastrectomy
in Morbidly Obese Subjects with Type 2 Diabetes Melli-
tus,” Surgery for Obesity and Related Diseases, Vol. 6,
No. 2, 2010, pp. 142-145.
http://dx.doi.org/10.1016/j.soard.2009.06.008
[12] M. Dietel, M. Ganger, A. L. Erickson and R. D. Crosby,
“Third International Summit: Current Status of Sleeve
Gastrectomy,” Surgery for Obesity and Related Diseases,
Vol. 7, No. 6, 2012, pp. 749-759.
[13] I. Braghetto, C. Davanzo, O. Korn, et al., “Scintigraphic
Evaluation of Gastric Emptying in Obese Patients Sub-
mitted to Sleeve Gastrectomy Compared to Normal Sub-
jects,” Obesity Surgery, Vol. 19, No. 11, 2009, pp. 1515-
1521.
[14] F. Abbatini, D. Capoccia, G. Casella, F. Coccia, F. Leon-
etti and N. Basso, “Type 2 Diabetes in Obese Patients
with Body Mass Index of 30-35 kg/m2: Sleeve Gastrec-
tomy versus Medical Treatment,” Surgery for Obesity and
Related Diseases, Vol. 8, No. 1, 2012, pp. 20-24.
[15] J. Vidal, A. Ibarzabal, J. Nicolau, et al., “Short-Term Ef-
Open Access SS

I. EL-SAYES ET AL.
Open Access SS
12
fects of Sleeve Gastrectomy on Type 2 Diabetes Mellitus
in Severely Obese Subjects,” Obesity Surgery, Vol. 17,
No. 8, 2007, pp. 1069-1074.
[16] F. Rubino and M. Gagner, “Potential of Surgery for Cur-
ing Type 2 Diabetes Mellitus,” Annals of Surgery, Vol.
236, No. 5, 2002, pp. 554-559.
http://dx.doi.org/10.1097/00000658-200211000-00003
[17] M. Rizzello, F. Abbatini, G. Casella, et al., “Early Post-
operative Insulin-Resistance Changes after Sleeve Gas-
trectomy,” Obesity Surgery, Vol. 20, No. 1, 2010, pp. 50-
55. http://dx.doi.org/10.1007/s11695-009-0017-2
[18] J. Ruiz-Tovar, I. Oller, A. Tomas, et al., “Midterm Impact
of Sleeve Gastrectomy, Calibrated with a 50-Fr Bougie,
on Weight Loss, Glucose Homeostasis, Lipid Profiles,
and Comorbidities in Morbidly Obese Patients,” The Ame-
rican Surgeon, Vol. 78, No. 9, 2012, pp. 969-974.
[19] F. Abbatini, D. Capoccia, G. Casella, E. Soricelli, F. Leo-
netti and N. Basso, “Long-Term Remission of Type 2
Diabetes in Morbidly Obese Patients after Sleeve Gas-
trectomy,” Surgery for Obesity and Related Diseases, Vol.
9, No. 4, 2013, pp. 498-502.
[20] M. Deitel, “Update: Why Diabetes Does Not Resolve in
Some Patients after Bariatric Surgery,” Obesity Surgery,
Vol. 21, No. 6, 2011, pp. 794-796.
[21] P. R. Schauer, B. Burguera, S. Ikramuddin, et al., “Effect
of Laparoscopic Roux-En y Gastric Bypass on Type 2
Diabetes Mellitus,” Annals of Surgery, Vol. 238, No. 4,
2003, pp. 467-485.