Validated Scoring Systems for Predicting Diabetes Remission After Bariatric Surgery

Abstract

Background:

Metabolic surgery is a new term used to emphasize the metabolic benefits of a variety of bariatric surgery procedures, particularly with relationship to the treatment of type 2 diabetes and its complications. Means by which the likely impact of metabolic surgery on diabetes could be assessed in individual patients would be of clinical value.

Methods:

Two main scoring systems (ABCD and DiaRem) have been proposed to predict remission of diabetes after metabolic surgery. We present a description of these systems, discuss the sources of differences in their predictive power, and suggest means by which to improve predictive power.

Results:

ABCD is more predictive in patients with intermediate and poorer scores. Neither score is validated as a means of predicting, which patients will benefit most from the repercussions of improved glycemic control in terms of complications.

Conclusion:

A composite scoring system derived from ABCD and DiaRem may improve prediction of postoperative remission rates. Such a system should be considered principally as an aid to decision-making. Excessive focus on prediction of long-term remission of type 2 diabetes mellitus should be avoided in favor of identifying which patients may stand to benefit most, even if full clinical remission is not achieved.

Introduction

Despite the marked advancement in the pharmacological and lifestyle-based approaches for treatment of type 2 diabetes mellitus (T2DM), <50% of patients achieve the therapeutic goal of a glycated hemoglobin (HbA1c) Diabetes Control and Complications Trial (DCCT) <7% (48 mmol/mol).¹ The American Diabetes Association defined the T2DM remission as return to “normal” measures of glucose metabolism (HbA1C in the normal range, fasting glucose <100 mg/dL [5.6 mmol/L]) of at least 1 year's duration in the absence of active pharmacologic therapy or ongoing procedures.² Patients with uncontrolled diabetes are more liable to develop microvascular and macrovascular diabetic complications.^3,4 Moreover, patients who develop T2DM without progress to microvascular complications have a much lower risk of early mortality.⁵

The term “diabesity” describes the overlap between T2DM and obesity,⁶ ∼50% of patients diagnosed with T2DM are obese.^7,8 The risk of developing T2DM increases by up to 20% for each 1 kg/m² increase in the body mass index (BMI).⁹ However, the additional risks added to T2DM by BMI is less than those added to T2DM by microvascular disease.⁵

The term “metabolic surgery” has been coined to emphasize the impact of bariatric procedures on T2DM and its complications.^10,11 Randomized trials clearly demonstrate that metabolic surgery results in improvements in glycemic control that exceed those achievable using medical treatment alone.^12–14 However, the extent and duration of T2DM remission rates after metabolic surgery remains less fully defined. The remission of T2DM is the most desirable impact of metabolic surgery, and prediction of this remission is one of the important aspects of patient selection.

Thus, we need information on reliable preoperative predictors to identify those candidates best placed to achieve the goal of durable or prolonged T2DM remission. This does not discount the importance of glycemic improvement per se, as the impact of improvement without remission on complications is likely to be substantial. On the contrary, if a scoring system was able to identify a smaller number of patients who were not likely to achieve a relative glycemic improvement with surgery versus medical treatment this would inform cost:benefit decision-making in these patients. This would potentially be another benefit of implementing a universal scoring system.

The criteria for defining remission of T2DM have changed over time.² Buchwald's meta-analysis used a lenient definition of remission of “no longer needing diabetes medication” and showed more than 80% remission of T2DM after gastric bypass surgery.¹⁵ Arterburn et al. used more stringent criteria after gastric bypass of HbA1c < 6% ≥ 180 days after the last prescription and found remission to be 68%.¹⁶ Ikramuddin et al. suggested that initial remission in patients with low BMIs might only be 40%, when a definition of HbA1c <6 was used.¹⁷ Schauer et al. found remission to be 22.4% at 5 years when a definition of HbA1c <6.0 with or without medication was used,¹⁴ while Mingrone et al. reported zero percent remission at 5 years after both Roux-en-Y gastric bypass (RYGB) and biliopancreatic diversion (BPD) when HbA1c <6% without medication was used.¹⁸

Metabolic Surgeries

Several laparoscopic bariatric procedures are available; RYGB, vertical sleeve gastrectomy (VSG), laparoscopic adjustable gastric band, and BPD classic or duodenal switch variant (BPD-DS), each with its own risk-to-benefit ratio. All other metabolic operations are considered to be investigational at this time.¹⁹ The American Society for Metabolic and Bariatric Surgery estimation of bariatric surgery numbers at 2015 showed that the most commonly performed procedures are VSG (53.8%) followed by RYGB (23.1%) and adjustable gastric banding (AGB, 5.7%).²⁰ Although BPD and BPD-DS are less commonly performed, they are often considered in extremely obese patients.²¹

RYGB and BPD result in greater remission rates for T2DM when compared with patients of similar weight loss after AGB.²² BPD-DS is characterized by the highest rates of T2DM remission, followed by RYGB, VSG, and then AGB.²³ However, several researchers have reported that VSG had a similar glycemic efficacy with gastric bypass in the treatment of morbidly obese patients with T2DM.^24–26 The major limitation of the data, however, is the variable definitions of remission that have been used.^2,15,16 Thus, the usage of the type of surgical procedure as a predictive value for T2DM resolution remains controversial.

The remission of T2DM following metabolic surgery may be transient, but commonly, patients can experience several years free of T2DM after metabolic surgeries, but many if not most patients will relapse over 10 years.²³ That said, retrospective data postRYGB indicates that in most cases relapse is partial. After 9 years, the number of antidiabetic medication is still 65% lower than preintervention with up to 70% reduction in mortality.²⁷ Patients with a higher disease burden may stand to accrue most benefit from significant improvements in glycemic control, even if clinical remission is only transient or does not occur.

This is particularly important given the emerging evidence showing that arrest of microvascular complications is possible after metabolic surgery.^28,29 Although no randomized controlled trials have compared the effects of metabolic surgery on hard renal endpoints as the primary outcome, the results of some published studies so far have demonstrated improved outcomes.^28,30 Navaneethan et al., cohort trial showed a decrease in the median albumin:creatinine ratio (ACR) from 36 to 27 mg/g at 6 months after RYGB.³¹ In a retrospective analysis of prospectively collected data, Heneghan et al. demonstrated that, of 52 patients undergoing metabolic surgery and followed up for 5 years, 58% achieved remission (ACR <30 mg/g).³² In the study of Miras et al., the mean retinal grading scores of 67 patients with T2DM were stable for 1 year after surgery, but improved significantly in the patients who were presented by retinopathy preoperatively.³³ Similar results were obtained in the Varadhan et al., retrospective study.³⁴ In a United States retrospective population-based study, the rates of patients developing blindness were lower in patients who underwent metabolic surgery than in the control group.³⁰ The mechanisms underlying these microvascular improvements or halting of disease progression are not fully understood, but it may be contributed to the surgical beneficial effect on systemic and tissue-specific inflammation, glycemic control, blood pressure, lipid profile, and increased production of gut hormones.³⁵

Although perioperative safety has improved greatly with the use of the laparoscopic approaches, surgery is still associated with multiple risk factors and long-term complications. Therefore, prioritizing patients most likely to have remission of T2DM after surgery may be valuable,³⁶ although this should not lead to exclusion of patients who are not likely to have durable remission. The risk of only focusing on remission of T2DM is that patients with a significant disease burden who may benefit significantly from vastly improved glycemic control could be excluded as they may not be good candidates for achieving remission. We do, however, need a systematic approach to allow more accurate communication with our patients.³⁶

Can We Predict T2DM Remission After Metabolic Surgery?

Among the six published risk prediction models, two were validated in one or more independent cohorts.^37–39 These two validated principal scoring systems (ABCD and DiaRem) have been developed to aid the selection of T2DM patients who are suitable candidates for surgery and to predict the short and long-term remission of T2DM.

ABCD scoring system

Lee et al. studied 236 patients with T2DM who underwent metabolic surgery between January 2006 and June 2009 with a median follow-up of 6 years, two patients died during the study period and 77 (32.6%) were lost to follow-up. The remaining 157 (66.5%) were included in the analysis, 117 (74.5%) underwent gastric bypass procedures (RYGB in 5 and Mini-Gastric Bypass [MGB] in 112), with the remaining 40 (25.5%) undergoing SG.⁴⁰ The four variables (age, BMI, C-peptide, and duration of T2DM) of the ABCD scoring system were used in this study.³⁷ ABCD scoring system is a four-point score system, the score for BMI, C-peptide, duration of diabetes according to analysis ranging from 0 (lowest value) to 3 (maximal value), and only one point is used for the age as shown in Table 1.⁴⁰ The total points for all variables in the ABCD ranged from 0 to 10 points.

Table 1.

Variables and Point Values Used for the Computation of Age, Body Mass Index, C-Peptide, and Duration of Diabetes (ABCD Score) ⁴⁰

Variable	Score 0	Score 1	Score 2	Score 3
Age (year)	≥40	<40
BMI (kg/m²)	<27	27–34.9	35–41.9	≥42
C-peptide (mmol/L)	<2	2–2.9	3–4.9	≥5
Duration of DM (years)	>8	4–8	1–3.9	<1

BMI, body mass index; DM, diabetes mellitus.

Analysis of 5 years follow-up of the Lee study demonstrated that mean HbA1c decreased from 8.3% to 6.0%, complete remission of T2DM (HbA1c <6.0% without antidiabetic medication for 1 year) was achieved by 111 (77.1%), and prolonged remission (HbA1c <6.0% without antidiabetes medication for 5 years) was achieved by 97 (61.8%) patients. Meanwhile, 27 (19.1%) of the patients achieved partial remission (HbA1c <6.5% for at least 1 year without antidiabetes medications) and 12 (8.8%) of the patients had improved disease (HbA1c <7.0% for at least 1 year).⁴⁰ The remission rate was zero in patients with C-peptide <2 ng/mL, BMI <27 kg/m², and overall ABCD scores <3. Patients with high preoperative ABCD scores (>8) maintained prolonged complete T2DM remission rates of 83% or greater as demonstrated in Table 2.⁴⁰

Table 2.

Type 2 Diabetes Mellitus Remission Rates in Lee et al. Study According to ABCD Diabetes Surgery Score System ⁴⁰

Score	Number of patients	Complete T2DM remission
0	0	0
1	4	0
2	1	0
3	8	1 (12.5%)
4	13	4 (30.8%)
5	15	5 (33.3%)
6	14	11(78.6%)
7	28	16 (57.1%)
8	24	18 (75.0%)
9	30	25 (83.3%)
10	20	17 (85.0%)
Overall	157	97 (61.8%)

T2DM, type 2 diabetes mellitus.

A major limitation of the ABCD system is the lack of inclusion of antidiabetic medication usage in the score calculation as this is a well-recognized predictor of outcome.^16,41 While it is logical to assume that preoperative BMI should be a valuable predictive tool, it was not noted to be a significant predictor of remission.^42,43 Lee et al., introduced a score that utilized C-peptide, a measure not universally tested in routine workup at bariatric centers, but that can be feasibly incorporated into preoperative assessment.⁴² The ABCD score was developed and validated in Asian patients.^37,40 Postoperative T2DM remission rate was not significantly different between Asian and non-Asian obese patients,⁴⁴ which suggests that ethnicity should not be an issue with ABCD but this, however, remains to be determined.

The DiaRem score

This score was developed to estimate the probability of T2DM remission after gastric bypass surgery.³⁸ The DiaRem score is based on four variables “age, HbA1c, medication, and insulin usage,” the points in this scoring system for the age and HbA1c ranging from 0 (lowest value) to 3 (maximal value). For the preoperative oral antidiabetes drugs, only a three-point score was used, but, a 10-point score was used for insulin injection treatment. The cutoff value for each of these variables is shown in Table 3.³⁸ The overall points for the DiaRem score range from 0 to 22.³⁶ Still et al.³⁸ demonstrated that 63% of 690 type 2 diabetic obese patients who had undergone RYGB surgery achieved partial or complete remission of 22% and 78%, respectively, at 1 year. Patients with lower scores in this system were predicted to have a higher probability of T2DM remission after gastric bypass surgery.³⁸

Table 3.

Calculation of DiaRem Score for the Probability of Type 2 Diabetes Mellitus Remission After Metabolic Surgery ³⁸

Variables	Score
Age
<40	0
40–49	1
50–59	2
≥60	3
HbA1c (%)
<6.5%	0
6.5–6.9%	2
7.0–8.9%	4
≥9.0%	6
Other diabetes drugs
No sulfonylureas or insulin-sensitizing agents other than metformin	0
Sulfonylureas and insulin-sensitizing agents other than metformin	3
Treatment with insulin
No	0
Yes	10
Total score calculated by adding each of the four variables	0–22

HbA1c, glycated hemoglobin.

The omission of information on T2DM duration and preoperative C-peptide in the scoring rubric for the DiaRem system is a major limitation. Moreover, the DiaRem score was developed and validated in patients undergoing RYGB and so may be limited in application.^38,39 Tharakan et al.⁴⁵ failed to show a useful predictive function of the DiaRem system in patients treated within a single bariatric unit in the United Kingdom, specifically in those who have a higher DiaRem score in whom rates of remission were significantly higher than predicted. This could be a consequence of DiaRem having been developed in an ethnically homogenous Caucasian population with predictive power lost when extrapolated to a multiethnic population.⁴⁵

DiaRem versus ABCD scores

A comparison of the DiaRem and ABCD scores for the prediction of T2DM remission was conducted using a retrospective cohort study, including 245 patients who had RYGB, MGB, laparoscopic single anastomosis, and duodenojejunal bypass with sleeve gastrectomy for the treatment of T2DM. After 1-year complete remission of T2DM as defined by HbA1c <6% was achieved in 53.1% of the patients, another 14.7% of patients achieved partial remission defined as HbA1c <6.5% and 11.4% achieved improved glycemic control.³⁶

Higher T2DM remission rates were achieved in patients with lower DiaRem scores (from 100% with the lowest score to 27.9% with the highest score). Conversely, in the ABCD system higher corresponded to higher T2DM remission rates (from 100% with the highest score to 9.1% with the lowest score). Both the ABCD and the DiaRem score predicted the success of the metabolic surgery. However, the ABCD system was better at predicting of T2DM remission in patients with intermediate scores (43.5 vs. 67.7%, p < 0.05) and poorer scores (27.9 vs. 9.1%, p < 0.05) as shown in Table 4.³⁶ In the ABCD system, the positive predictive value for the intermediate score (5–6) was 68%, given that 42 of the 62 patients in this category achieved complete remission. An intermediate score in the DiaRem system (8–12) yielded a positive predictive value 43.5%, given that 47 of the 108 patients achieved complete remission. Notably, while 44% of patients fulfilled the intermediate score criteria, in DiaRem the percentage meeting the intermediate score criteria in the ABCD was markedly lower at 25%. This indicated a greater stringency of the ABCD criteria, and this explains the 1.5-folds improvement in the positive predictive power of the ABCD system for intermediate ranking.

Table 4.

Comparison of DiaRem and ABCD Score for the Result of Lee et al. Study ³⁶

DiaRem score		ABCD score
Score	Complete remission (%)	Score	Complete remission (%)
0–2	100%	10–9	100%
3–7	85.3%	8–7	88.6%
8–12	43.5%	6–5	67.7%
13–17	38.1%	4–3	39.8%
18–22	27.9%	2–0	10.7%
Total	53.1%	Total	53.1%

The postoperative diabetes remission rate is mainly related to the preoperative severity of T2DM,^44,46,47 which can be indirectly estimated by the duration of T2DM as included in the ABCD score and the antiglycemic medication as used in the DiaRem score. At the same time, it can be directly measured by C-peptide, which is used in the ABCD score, and HbA1c, which is included in the DiaRem score. The question arises therefore as to why the ABCD system is a better predictor of remission in patients with intermediate or poor scores? We will sequentially address the relative importance and meaning of preoperative BMI, beta cell function (C-peptide), HbA1c, and duration of T2DM as predictors of postoperative T2DM remission rates, in an attempt to answer this question. At the same time, we advocate developing a consolidated scoring system that incorporates a biochemical assessment of glycemic control, β-cell function, and clinical data on disease duration, which could be achieved using these variables.

The Impact of Preoperative BMI in the Prediction of T2DM Remission

Although it is theorized that retention of insulin secretory activity and sensitivity can be implicated in some cases of very high BMI, it is widely accepted that the relative risk of T2DM increases with higher BMI within the obese range.⁴⁸ Adipose tissue in obese patients with high BMI acts as an endocrine organ producing C-reactive protein, tumor necrosis factor-alpha, and other proinflammatory molecules. The elevation in theses cytokines leads to disturbance of the insulin resistance in the liver, muscle, and adipose tissue.⁴⁹ Also, these types of patients showed postprandial and postabsorptive elevation in the fatty acid level in both systemic and portal circulation, which promotes liver gluconeogenesis.⁵⁰ It is clear that patients with high BMI have a high risk of developing T2DM due to increased insulin resistance, but the severity of T2DM in patients with lower BMI can occur due to defective insulin secretion.⁴³ T2DM remission can occur within days or weeks after metabolic surgeries, before any significant change in BMI.^38,51 The postoperative decrease in BMI, therefore, cannot explain early remission, but may contribute to the maintenance of T2DM resolution over time. On the contrary, postoperative weight regain does associate with an increase in the risk of T2DM relapse.^52,53

The Lee et al.⁵⁴ series, showed an increase in T2DM remission rates in patients with higher BMI. However, due to the nonsignificant difference in the postoperative T2DM remission rates at different BMI groups, this could not be preoperatively predicted.⁵⁴ The same results were obtained by the Guenzi et al. study, in which the T2DM remission rates as defined by HbA1c <6% was 80%, 86.6%, and 91.7% for patients with BMI <40 kg/m², 40–50 kg/m², and >50 kg/m², respectively.⁴³ These results are comparable with most of the published studies that used the same definition of T2DM remission.^43,44,55 Nevertheless, some studies approved the use of BMI as a positive preoperative predictor of T2DM resolution.^15,56 So, the usage of BMI as a predictive value for T2DM resolution remains controversial.

The Impact of C-Peptide and HbA1c in the Prediction of T2DM Remission

The previously published studies showed that better preserved β-cell function results in maximizing the effect of metabolic surgery by increasing insulin secretion and securing remission of T2DM.^44,46,47 Thus, the preoperative assessment of β-cell function and insulin secretion capacity can be put forward as a crucial element of assessing the degree of preserved endocrine pancreatic function and, consequently, prediction of the postoperative remission.

C-peptide levels assess the function of β-cells of the pancreas as it serves as a stable proxy for the level of insulin secretion, given that it is not extracted during hepatic first pass as is the case with insulin.⁵⁷ Most published studies confirm the positive relationship between C-peptide levels and the postoperative T2DM remission rate.^37,44,57,58 Low C-peptide levels in diabetic obese patients indicate poor preservation of β-cells function, which has exceeded the capacity for compensation to counter the increase in peripheral insulin resistance.⁵⁹ Consequently, C-peptide has been described as a predictor of T2DM remission after metabolic surgery.^44,60,61 Although the perioperative safety of metabolic surgery has improved greatly with the use of the laparoscopic approach, a real risk to patients remains. Moreover, this type of surgery remains expensive and not financially covered by most of the insurance companies.⁶² So, predicting the individual responses to surgery is essential for the decision-making.⁶³ Despite the C-peptide not being routinely measured during preoperative workup, it could be one of the most fundamental preoperative predictors of postoperative T2DM improvement and remission.^{18,37,40,44,64}

Elevated HbA1c is considered an indicator of long-standing hyperglycemia and in turn constitutes a glucotoxic stimulus in relationship to the secretory function of β-cells in poorly controlled T2DM.⁶⁵ The results of Wang et al. meta-analysis study that included 1149 diabetic obese patients from 13 different studies demonstrate a significant association between the preoperative HbA1c level and postoperative remission rates.⁴⁴ Thus, diabetic obese patients with high baseline HbA1c levels are associated with lower remission rates. HbA1c levels are, however, of course, dependent upon the form, intensity, and response to antidiabetic medications in individual patients, and effective drug responses could result in more favorable HbA1c results, which in reality are masking endocrine pancreatic decompensation.^66,67 Several published studies report that insulin use is predictive of less complete resolution of DM, whereas less intensive requirements for sustaining preoperative glycemic control (diet and monotherapy) are associated with high remission rates.^{16,41,68–70}

The Impact of T2DM Duration in the Prediction of Its Remission

T2DM occurs due to impairment in insulin resistance in the liver, skeletal muscles, and adipose tissue, accompanied by a decrease in insulin secretion due to variable degrees of pancreatic β-cells damage. The longer duration of T2DM leads to more insulin resistance and reduced number and function of β-cells over time. Those patients may already have lost 50–80% of their beta cell function by the time their T2DM is diagnosed.⁷¹ The function of the β-cells, not insulin resistance, is the key predictor of the postoperative T2DM remission.^72,73 Preoperative duration of T2DM is reflected by the deterioration in the number and function of β-cells, as a natural course of the disease. Subsequently, it is recognized as a good predictor factor.^38,74–76 Therefore, earlier management of T2DM increases its postoperative remission rates.⁷⁷

Patients in the Guenzi et al.⁴³ study were divided into two groups according to their preoperative T2DM duration. Patients with a short duration (<3 years) showed T2DM remission rate of 93.7%, and those with a long-standing T2DM (>3 years) had a remission rate of 32%.⁴³ Also, in the 1-year follow-up of Khanna et al. study, the remission rate was 42.9% for patients with <5 years T2DM duration and 7.7% for patients with a longer disease duration (p < 0.05).⁷³ Wang et al. analysis of 1555 diabetic patients from different 13 studies showed a significant link between preoperative T2DM duration and postoperative remission rate (p < 0.01). Thus, T2DM patients with long diabetes duration have a lesser remission rate.⁴⁴

The Impact of Other Variables in the Prediction of T2DM Remission

Wang et al.⁴⁴ conducted a meta-analysis of 1113 diabetic patients from 13 different studies. Of these 13 studies, three studies were conducted in the Asia, two in Europe, seven in the United States of America, and one in Oceania. The results of this meta-analysis showed an insignificant association between gender and the postmetabolic surgery T2DM remission. Thus, gender may not be a predictor of T2DM remission after bariatric surgery. At the same time, the postoperative T2DM remission rate was not significantly different between Asian and non-Asian obese patients.⁴⁴

Theoretically, increased visceral and subcutaneous adiposity are major risk factors for insulin resistance. The increase in visceral adipose tissue associated with a decrease in the pancreatic β-cell function, volume >5059 cm³ in moderate and severe obese patient predicted prevalent impaired fasting glucose or T2DM.⁷⁸ There are longitudinal relationships between abdominal adiposity, inflammatory mediators, and direct measures of in vivo insulin action.^78,79 In addition, the leptin and adiponectin expression is higher in subcutaneous fat compared with visceral adipose tissue.^80,81 Published studies show that body composition and regional fat distribution are an important determinant of metabolic outcomes after bariatric surgery, the visceral-to-subcutaneous fat ratio being a significant independent predictor of the postoperative remission of T2DM.^60,82 However, the effect of the visceral and peripheral fat removal remains controversial, and there is still an insufficient evidence base to support its use for the remission of T2DM.^83–85 The methods for estimating body composition such as bioelectrical impedance analysis, dual energy X-ray absorptiometry (DEXA) scan or air displacement plethysmography are not universally available and can present difficulties in terms of precision in longitudinal assessment. So use of body composition as a predictor of T2DM remission after metabolic surgery while scientifically valid may be difficult to implement in a universal scoring system.

Conclusion

It is possible to predict a large proportion of patients who will have T2DM remission after metabolic surgery, using the ABCD and DiaRem score systems. The postoperative remission rate is related to the preoperative severity of T2DM. Those who are predicted to have a low chance of T2DM remission should not, however, be considered necessarily to be “poor candidates” as they may still have multiple benefits after surgery. Therefore, the indications of metabolic surgery should be tailored to each patient's needs.

Which scoring system is best and whether indeed there is any clinical utility remains controversial. Most researchers agree that older patients with higher BMI, insulin usage, higher HbA1c level, lower C-peptide levels, and a long duration of T2DM have a lower probability of T2DM remission. However, whether this matters for long-term morbidity or mortality has not been studied. The postoperative lower remission rates in long-standing T2DM relates to the residual β-cell mass in these patients. The C-peptide level is a good indicator for the functioning β-cell mass. At the same time, HbA1c acts as an indicator of the direct glucotoxic effects of the long-standing hyperglycemia on the secretory function of β-cells. Thus, the combination of lower HbA1c and higher C-peptide in patients with a short duration of T2DM and oral hypoglycemic medication should be associated with the highest rates of postoperative remission. The duration of T2DM is likely the most important and practical predictive factor in most cases, as it subsumes the cumulative impact of long-standing hyperglycemia and pancreatic overcompensation. However, patients with a short duration of T2DM also have the lowest rates of T2DM complications and mortality compared with patients who have a longer duration of T2DM.

We, therefore, advocate the development of a consolidated scoring system that incorporates a biochemical assessment of glycemic control, β-cell function, and clinical data on disease duration which deemphasizes any independent predictive value of BMI, but specifically predicts not only remission but also the numbers needed to treat to prevent one microvascular or macrovascular complication from occurring. More targeted, prospective, and retrospective, clinical trials could be used to validate such a standard universal score for prediction of diabetic remission and prevention of diabetic complications after metabolic surgery. Studies with more than 5 years of follow-up will be beneficial to assess the rate of long-term relapse and development of diabetic complications. As with other scoring systems, complex clinical problems may arise when additional individual patient factors are considered in the totality of decision-making.

Footnotes

Acknowledgments

M.A. and N.G.D. conceived the idea of the article and drafted the text. C.W.l.R. provided reviews of draft versions of the article and advised on the direction of the article. Werd al-Najim provided assistance with English language and grammar. M.A. was funded by a research award by the Ministry of Higher Education and Scientific Research of Egypt. Funding at the Dublin laboratory arises from a Science Foundation Ireland President of Ireland Young Researcher Award to C.W.l.R. (12/YI/B2480) and the Health Research Board (USIRL-2016-2). C.W.l.Roux (PI) and N.G.D. are coinvestigators on a grant from the Swedish Research Council (Medicine and Health) (2015-02733) at University of Gothenburg.

Author Disclosure Statement

I can confirm that all coauthors have approved the article, it is not published or under consideration elsewhere, and no authors have any Conflicts-of-Interest to declare.

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