Early outcome of bariatric surgery for the treatment of type 2 diabetes mellitus in super-obese Malaysian population.

INTRODUCTION: Despite many challenges, the benefit of bariatric surgery in super-obese population remains irrefutable with significant improvement in metabolic syndrome and quality of life. There are currently no published data from Malaysia on this topic. OBJECTIVE AND
METHODOLOGY: A single-centre retrospective study aimed at analysing the outcome of laparoscopic bariatric surgery on super-obese Malaysians with type 2 diabetes mellitus (T2DM) at 12 months following surgery. Demographic details, glycaemic control and weight-loss parameters were analysed.P < 0.01 was considered statistically significant.
RESULTS: Of the 33 patients, 55% were women and 45% were men with a mean age of 40 ± 11 years and body mass index (BMI) of 59.3 ± 9.0 kg/m2. Majority of patients were of Malay ethnicity (82%). Malaysian-Indians and Malaysian-Chinese each accounted for 9% of total case volume. The three types of laparoscopic bariatric surgery recorded in this study were sleeve gastrectomy (82%), Roux-en-Y gastric bypass (9%) and mini-gastric bypass (9%) with operative time of 103.5 ± 31.1, 135.8 ± 32.6 and 116.2 ± 32.3 min, respectively. Percentage total body weight loss was 33.11% ± 9.44% at 12 months following surgery (P < 0.01). BMI change and percentage excess BMI loss showed similar improvement. Glycosylated haemoglobin and fasting blood sugar decreased from pre-operative values of 7.0% ± 1.0% and 7.0 ± 0.9 mmol/L to 5.6% ± 0.4% and 5.0 ± 0.6 mmol/L at 12 months (P < 0.01). Remission of T2DM was noted in 93% of patients. There was no correlation between weight loss and improvement in glycaemic status.
CONCLUSION: There are significant weight loss and improvement of glycaemic control at 12 months post-laparoscopic bariatric surgery among super-obese Malaysians.

INTRODUCTION

Obesity is a global health concern that has shown no sign of slowing down over the past three decades.[1] Malaysia has not been spared of this growing pandemic with 45.3% of our population identified as either overweight or obese.[2] The increasing prevalence of obesity in Malaysia has also led to a rise in type 2 diabetes mellitus (T2DM) affecting 3.5 million (17.5%) individuals in 2015.[3] The prevalence of obesity and T2DM has been notably higher amongst women and Malaysians of ethnic Indian background.[345] In 2010 alone, the global expenditure on diabetes was estimated to be approximately $376 billion forcing member states of the World Health Organization to take immediate notice and introduce plans to combat the rise of obesity and diabetes by 2025.[16] Previous studies have established the superiority of bariatric surgery over medical treatment for weight loss and comorbidity resolution in obese subjects.[789] There is, however, a relative scarcity of literature focusing on the effect of bariatric surgery on the super-obese (body mass index [BMI] ≥50) with none from Malaysia. The purpose was of this study was to assess weight loss and comorbidity resolution among super-obese Malaysians following bariatric surgery.

METHODOLOGY

In this single-centre retrospective, cohort study, medical records of all patients who fulfilled the inclusion criteria (BMI of ≥50 kg/m2, diagnosed with T2DM and undergone primary bariatric surgery between 1st January 2012 and 31st October 2015) were retrieved. Pre-operative demography, biophysical parameters, comorbidity status including biochemical markers and medication list were reviewed and tabulated in an excel sheet. Operative details were noted. Post-operative weight and biochemical changes at various pre-determined time intervals (3, 6 and 9 months and 1 year) were also included.

T2DM was defined as a fasting serum glucose (fasting blood sugar [FBS]) ≥7 mmol/L or glycosylated haemoglobin (HbA1c) ≥6.5%. Partial remission of T2DM was defined as HbA1c <6.5% and FBS between 5.6 and 6.9 mmol/L with no pharmacological therapy for at least 1-year duration. Complete remission of T2DM was defined as HbA1c <6% and FBS <5.6 mmol/L with no pharmacological therapy for at least 1 year.[10] Improvement of metabolic state was defined as lowering of HbA1c >20% with reduced medication from preoperative state.[11]

Statistical analysis

Statistical analyses were performed with MATLAB version 2013a. Paired continuous data were analysed using t-test (two-tailed), and unpaired continuous data were analysed using single-factor ANOVA. Categorical data were presented as percentage. Pearson's correlation coefficient (ρ) was estimated to establish the functional relationship between weight loss and parameters of glycaemic status. P < 0.01 was considered statistically significant, with a power of 90% and confidence interval of 95%.

Operative procedures

Before surgery, patients are assessed by a multidisciplinary team which includes a bariatric surgeon, dietician, endocrinologist and physiotherapist. The patients are then reviewed by an anaesthetist to determine fitness for surgery. Referral to a respiratory physician, cardiologist and nephrologist is done when necessary. They are also advised to adhere to a very low-calorie diet of 800 calories per day for a minimum of 2 weeks before surgery to facilitate hepatic volume reduction.

Surgical technique

Laparoscopic sleeve gastrectomy

A standard sleeve is fashioned using linear staplers over a 36 Fr orogastric Bougie, 4 cm from the pylorus distally and 1 cm away from the Angle of His proximally.

Laparoscopic Roux-en Y Gastric bypass

It involves formation of a 50 cc gastric pouch, antecolic gastrojejunal anastomosis creation with a Roux limb of 150 cm and biliary limbs of 100 cm using a linear stapler. The gastrojejunostomy of 2.5 cm in diameter is created using the linear stapler.

Laparoscopic mini gastric bypass

It involves the creation of a lesser curvature-based long gastric pouch over a 36 Fr oro-gastric Bougie and a 200 cm biliopancreatic limb and an antecolic gastrojejunostomy.

Post-operative management and follow-up protocol

Post-operatively, patients are allowed liquids during the 1st post-operative week and gradually advanced to semiliquid, blended diet and so forth over the subsequent weeks. The patient is discharged on the postoperative day 2–3. Outpatient review is done at week 1 for wound inspection and subsequently at the 1st, 3rd, 6th and 12th month following surgery for the 1st year followed by 6 monthly for the next 2 years and yearly thereafter.

RESULTS

A total of 33 patients were included in this study, of which 18 (55%) were women and 15 (45%) men. The mean age was 40 ± 11.5 years (range 18–69 years). The mean BMI was 59.4 ± 9.0 kg/m2. Malaysians of Malay ethnic background made up almost 81.8% of the study population, while Malaysians of Chinese and Indian ethnicity accounted for 9.1% each, respectively. A total of 27 patients (81.8%) underwent laparoscopic sleeve gastrectomy (LSG). Three patients (9.1%) had laparoscopic Roux-en Y gastric bypass (LRYGB), while the remaining three patients (9.1%) had laparoscopic mini-gastric bypass (MGB) [Table 1]. Mean operative time for LSG, LRYGB and MGB was 103.5 ± 31.1, 135.8 ± 32.6 and 116.2 ± 32.3 min, respectively. Patients who underwent LSG had shorter duration of stay as compared to those who underwent LRYGB or MGB. There were no peri-operative mortalities recorded in this cohort. There were, however, two cases of superficial surgical site infection which was successfully treated with 1 week of oral antibiotics [Table 2]. Three patients defaulted follow-up at 12 months post-surgery and were not included in further statistical analysis.

Table 1

Baseline characteristics of the study population

Observation parameter	Laparoscopic sleeve gastrectomy (n=27)	Laparoscopic Roux-en-Y gastric bypass (n=3)	Laparoscopic mini-gastric bypass (n=3)	All procedures combined (n=33)
Age (years), mean±SD	39.2±11.2	49.7±14.7	42.3±10.7	40.4±11.5
Initial BMI (kg/m2)	60.9±9.3	52.6±2.5	52.8±1.5	59.4±9.0
Female (n)	15	2	1	18
Male (n)	12	1	2	15
Race (n)
Malay	23	2	2	27
Indian	2	1	0	3
Chinese	2	0	1	3

BMI: Body mass index, SD: Standard deviation

Table 2

Duration of surgery, length of stay in hospital, peri-operative morbidity and peri-operative mortality details

	Laparoscopic sleeve gastrectomy (n=27)	Laparoscopic Roux-en-Y gastric bypass (n=3)	Laparoscopic mini-gastric bypass (n=3)
Mean operative time (min)	103.5±31.1	135.8±32.6	116.2±32.3
Hospital length of stay (days)	3.1±0.3	4.0±0.0	4.0±0.0
Conversion to open	0	0	0
30-day morbidity	1	1	0
30-day mortality	0	0	0

Mean percentage total body weight loss (%TBWL) at 1 year was statistically significant (P < 0.01) and demonstrated an increase from 15.2% ± 6.8% to 25.1% ± 7.1% and 34.2% ± 8.8% at 3 months, 6 months and 12 months interval following surgery [Figure 1]. Similarly, mean BMI, change in BMI and percentage excess BMI loss (%EBMIL) all showed significant improvement at 1 year [Table 3]. Interestingly, women demonstrated a significantly higher %TBWL at 3 months following surgery when compared to men (single-factor ANOVA, P < 0.01). At 12 months, however, there was no significant difference between the two sexes [Figure 2].

Figure 1

Changes in mean body weight, mean body mass index, percentage excess body mass index loss and percentage of total body weight loss in super-obese Malaysians at specific time interval following laparoscopic bariatric surgery

Table 3

Weight loss and comorbidity resolution in super-obese patients 1 year following laparoscopic bariatric surgery

Observation parameter	Pre-surgery (n=30)	1-year post-surgery (n=30)	P (two-tailed paired t-test)
Weight (kg), mean±SD	156.1±29.4	101.4±16.4	<0.01*
Change in TBWL (%), mean±SD	0.0±0.0	34.2±8.8	<0.01*
BMI (kg/m2), mean±SD	59.8±9.3	38.9±4.5	<0.01*
Change in BMI	0.0±0.0	21.0±8.2	<0.01*
Excess BMI loss (%), mean±SD	0.0±0.0	59.3±12.5	<0.01*
HBA1c (%), mean±SD	7.0±1.0	5.6±0.4	<0.01*
FBS mmol/L, mean±SD	7.0±0.9	5.0±0.6	<0.01*

*Statistically significant difference. TBWL: Total body weight loss, SD: Standard deviation, HBA1c: Glycosylated haemoglobin, FBS: Fasting blood sugar, BMI: Body mass index

Figure 2

Percentage total body weight loss for men and women at 3 months, 6 months and 1 year following laparoscopic bariatric surgery

There was also significant improvement in diabetic status of our study population. Mean HbA1c and FBS both decreased from pre-operative values of 7.0% ± 1.0% and 7.0 ± 0.9 mmol/L to 5.6% ± 0.4% and 5.0 ± 0.6 mmol/L, respectively, at 12 months following surgery (P < 0.01) [Figure 3]. Approximately 93% of our patients who were previously on some form of anti-diabetic treatment, no longer required medication at 12 months following surgery [Table 4]. Complete remission of T2DM was noted in 63.0% of the patients, while partial remission was seen in 30.0%. Improvement in metabolic state, on the other hand, was documented in the remaining 7.0% of patients. There were no cases of worsening glycaemic status in our study population [Figure 4]. There was no correlation between %TBWL and percentage change in HBA1c or %TBWL and percentage change in FBS levels at 3 months [Figure 5a], 6 months [Figure 5b] and 1 year [Figure 5c] following surgery.

Figure 3

Changes in mean glycosylated haemoglobin and mean fasting blood sugar in super-obese Malaysians at 3 months, 6 months and 1 year following laparoscopic bariatric surgery

Table 4

Statistical analysis of effectiveness of laparoscopic bariatric surgery on super-obese patients based on medication requirement at the end of 1 year following surgery

Observation parameter	Number of patients requiring medication pre-surgery	Number of patients requiring medication 1-year post-surgery	P (Z-test)
Need for monotherapy OHA only (n)	21	2	<0.01*
Need for >1 OHA (n)	5	0	0.025
Need for insulin + OHA (n)	4	0	0.414

*Statistically significant difference. OHA: Oral hypoglycemic agent

Figure 4

Effect of laparoscopic bariatric surgery on glycaemic status of super-obese Malaysians at 1 year

Figure 5

(a) Correlation pattern of percentage change in glycosylated haemoglobin and fasting blood sugar levels as a function of percentage change in total body weight loss at 3 months following laparoscopic bariatric surgery, (b) correlation pattern of percentage change in glycosylated haemoglobin and fasting blood sugar levels as a function of percentage change in total body weight loss at 6 months following laparoscopic bariatric surgery, (c) correlation pattern of percentage change in glycosylated haemoglobin and fasting blood sugar levels as a function of percentage change in total body weight loss at 1 year following laparoscopic bariatric surgery

DISCUSSION

Performing any laparoscopic procedure let-alone bariatric surgery in patients with BMI >50 kg/m2 is a mammoth undertaking. Mason et al. were among the earliest to report on the technical challenges of performing bariatric surgery in the super-obese population. This included manoeuvring beneath a large fatty liver, bulky omentum, thick abdominal wall and increased abdominal wall torque.[12] Brolin et al. and Artuso et al. reported longer operative time, increased hospital stay and higher morbidity as well as mortality risks in the super-obese group undergoing bariatric surgery.[1314] Despite huge improvements in surgical skillsets and technological advances in the field of minimally invasive surgery, over the last two decades, some of those challenges mentioned still persist albeit in a much smaller percentage. Having said that numerous modern-day publications have been noted to be in favour of bariatric surgery, given the undisputable and overwhelmingly positive results seen with regard to weight loss and improvement of obesity-related comorbidities across all classes of obesity as compared to conservative or medical therapy alone.

On the subject of recommended surgical procedure in patients with BMI >50 kg/m2, there seems to be more debate than there is consensus. With a buffet of procedures available, today's surgeon can be seen as spoilt for choices. Prachand et al. retrospectively analysed the outcome of 350 super-obese patients who underwent laparoscopic duodenal switch (LDS, n = 198) and LRYGB (n = 152) at 1 year and 3 years following surgery. The study noted that %EBWL at follow-up was greater for LDS than LRYGB (12 months, 64.1% vs. 55.9%; 18 months, 71. 9% vs. 62.8%; 24 months, 71.6% vs. 60.1%; 36 months, 68.9% vs. 54.9%; P < 0.05). The 30-day mortality was not significant between the two groups.[15] A separate paper published by Prachand et al. 2 years later also went on to demonstrate the superiority of LDS in comorbidity resolution as compared to LRYGB. The study showed that diabetes (100% vs. 60%), hypertension (68.0% vs. 38.6%) and dyslipidaemia (72% vs. 26.3%) resolution was significantly higher in the group that underwent LDS compared to the LRYGB group (P < 0.05). Improvement in gastroesphageal reflux disease (GERD) symptoms, however, was significantly higher in the LRYGB group (76.9% vs. 48.57%; P < 0.05).[16] In a randomised control trial by Søvik et al., 60 super-obese patients were divided into LDS and LRYGB and followed up for 1 year. Similar to previous report, the %EBMIL was also notably greater after LDS (75% vs. 54%; P < 0.001). However, the operating time and duration of ward stay were significantly higher in the LDS group (P < 0.001). The 30-day peri-operative morbidity rate was higher in the LDS group compared to the LRYGB group.[17]

A double-blinded randomised control study by Svanevik et al. studied the perioperative outcomes of laparoscopic proximal gastric bypass (n = 56) and distal gastric bypass (n = 57) in super-obese patients. The biliopancreatic limb in both groups was fixed at 50 cm. The alimentary limb in the proximal gastric bypass group was fixed at 150 cm, while those in the distal bypass group were given a common channel of 150 cm. Duration of surgery was significantly longer in the distal bypass group (P < 0.001). The distal bypass group was also associated with severe peri-operative morbidity with six patients requiring re-operations for various reasons such as stapler line bleed, internal herniation, anastomotic leak, entero-enterostomy obstruction and iatrogenic bowel injury.[18] A 2-year follow-up study of the same cohort noted no difference in weight loss between the two groups. Reduction of HbA1c and total cholesterol was significantly higher in the distal bypass group (P < 0.001) as well as occurrence of secondary hyperparathyroidism and loose stool. Three patients in the distal gastric bypass group required revision surgery with elongation of the common channel for liver failure and protein-caloric malnutrition.[19]

There have been numerous studies published on early outcome following LSG in super-obese population with less favourable results unlike studies with longer duration of follow-up.[20] A mid-term retrospective study by Hong et al. analysed the 3-year outcome following bariatric surgery in 607 super-obese individuals. A total of 501 patients underwent LRYGB while the remaining 106 patients underwent LSG. At the end of 36 months, there was no difference in %EWL between the two groups. Both groups showed significant improvement in HBA1c with no statistical difference between the two groups. The results of this study suggest that LSG is equally effective as LRYGB as a stand-alone procedure for super-obese individuals.[21]

In recent years, there has been an increase in the popularity of MGB as a stand-alone procedure for both morbid and super-obese individuals. Lemanu et al. in a retrospective study involving 169 patients who underwent MGB and 118 patients who underwent LSG, demonstrated significantly higher %EWL in the MGB group compared to the LSG group (66% vs. 57%; P < 0.0001).[22] There is, however, a paucity of studies with longer duration of follow-up in this subset of patients.

Besides the type of surgery, the surgical approach has also been a subject of much debate.

On the one hand, there are those who believe that a single stage laparoscopic procedure is sufficient to bring about adequate weight loss and comorbidity control.[21222324] On the other hand, proponents of the two-stage laparoscopic approach insist on a primary restrictive procedure followed by a more malabsorptive procedure at a later interval.[2526] The staged approach is intended to facilitate risk reduction through initial weight loss, hepatic volume reduction and comorbidity control, allowing for a second procedure to be performed in a less stressful situation. Varying results have been published with regards to outcome of surgery depending upon the type of procedure and approach be it one stage or two stages; however, the final decision remains a prerogative of the surgeon having taken all factors into consideration including input by the multidisciplinary team and patients themselves. Most importantly, the procedure of choice should be able to deliver significant weight loss over a sustainable period, demonstrate improvement in associated comorbidities and present a low rate of morbidity as well as mortality.

CONCLUSION

Our study confirms significant improvement in BMI, %TBWL, HbA1c and FBS at 12 months post-laparoscopic bariatric surgery among super-obese Malaysians. Our data also show a lower morbidity and mortality rate when compared to previously published reports. This may be explained by the multi-disciplinary approach that is adopted in our institution, the practice of specialised care given to high-risk patients, implementation of dietary caloric restriction of 800 kcal per day for 2 weeks before surgery to reduce hepatic volume and the adoption of enhanced recovery after surgery protocol whenever feasible. We were not able to effectively compare the outcome measures between the three bariatric procedures to determine superiority of one over the other due small number of patients especially in the LRYGB and MGB groups. Whether these patients regain weight or not remains to be seen and is beyond the scope of this study. A case-matched or prospective randomised control trial with a larger sample size and longer follow-up period could offer a better insight into the best surgical option for patients with BMI ≥50 kg/m2.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.