Introduction: Given the lack of research on the relationship of post-surgery dumping syndrome and eating disturbances, the purpose of the present longitudinal study was to investigate whether dumping after obesity surgery is associated with pre-/postoperative eating disorder symptoms or addiction-like eating beyond the type of surgery, gender, health-realted quality of life (HRQoL) and anxiety/depressive symptoms. Methods: The study included 220 patients (76% women) before (t0) and 6 months after (t1) obesity surgery (sleeve gastrectomy [n = 152], Roux-en-Y gastric bypass [n = 53], omega loop gastric bypass [n = 15]). The Sigstad Dumping Score was used to assess post-surgery dumping syndrome. Participants further answered the Eating Disorder Examination Questionnaire (EDE-Q), Yale Food Addiction Scale 2.0 (YFAS 2.0), Short-Form Health Survey (SF-12), and Hospital Anxiety and Depression Scale (HADS) at t0 and t1. Results: The point prevalence of symptoms suggestive of post-surgery dumping syndrome was 33%. Regression analyses indicate an association of dumping with surgical procedure (bypass), female gender, reduced HRQoL, more anxiety/depressive symptoms, and potentially with binge eating but not with eating disorder symptoms in general or with addiction-like eating. Conclusion: The current study failed to show a close relationship between the presence of self-reported dumping syndrome and eating disorder symptoms or addiction-like eating following obesity surgery. Further studies with longer follow-up periods should make use of clinical interviews to assess psychosocial variables and of objective measures to diagnose dumping in addition to standardized self-ratings.

Obesity surgery is the method of choice in the treatment of persistent severe adiposity and associated diseases such as type 2 diabetes mellitus, hypertension, and dyslipidemia [1‒7]. In addition to sustained weight loss and positive effects on the patient’s quality of life and mental health [7‒11], surgery can also be associated with undesirable side effects. Therefore, benefits of surgical obesity treatment have to be balanced against negative outcomes. One such possible negative consequence of surgery is dumping syndrome, which may occur, e.g., due to the altered gastrointestinal anatomy and rapid passage of undigested food into the small bowel [12‒14]. Dumping syndrome can be differentiated into early (i.e., occurs within the first hour after a meal) and late dumping syndrome (i.e., occurs 1–3 h after a meal), with the former being the most common [15]. Possible symptoms of early dumping syndrome include gastrointestinal (e.g., abdominal pain, nausea, diarrhea, borborygmi, cramps, vomiting) and vasomotor symptoms (e.g., desire to lie down, dizziness, sweating, tachycardia, hypotension, flushing, and rarely syncope) [14‒16]. Late dumping syndrome is characterized by hypoglycemic symptoms (e.g., heart palpitations, tremors, weakness, sweating) [15].

Prevalence rates for dumping syndrome after obesity surgery vary between 20 and 40% [12‒14, 17‒19]. With few exceptions [20], bypass surgery is associated with a higher risk for postoperative dumping than other types of surgery such as, e.g., sleeve gastrectomy or gastric banding [12, 15, 21‒24]. Past studies further indicate that women are more likely to suffer from postoperative dumping than men [17, 19, 23].

Dumping syndrome may result not only in a variety of physical but also mental complaints (e.g., anxiety and depressive symptoms) [25] and reduced health-related quality of life (HRQoL) [12, 15, 22, 25, 26]. Although it may seem plausible from a clinical perspective that dumping may be associated with non-normative postoperative eating behaviors such as loss of control or addiction-like eating, this issue has been little studied. Investigation of 50 post-surgery patients failed to show differences in eating-related symptoms (i.e., cognitive restraint, uncontrolled eating, and emotional eating) between patients with (42% of the sample) and patients without dumping syndrome [19]. In a longitudinal study with 183 participants, postoperative gastrointestinal symptoms were related to postoperative loss of control eating [27].

Patient-related factors – such as eating behavior – potentially associated with dumping syndrome following obesity surgery remain poorly understood. Given the lack of research on the relationship of post-surgery dumping syndrome and potentially disturbed eating behavior, the purpose of the present longitudinal study was to assess the occurrence of dumping syndrome 6 months after obesity surgery and to investigate whether post-surgery dumping is associated with pre-/postoperative eating disorder symptoms or addiction-like eating beyond the type of surgery, gender, HRQoL, and anxiety/depressive symptoms. The 6-month period was chosen because dumping syndrome can occur soon after surgery [22] and because it is assumed that pre-operative non-normative eating behavior, including addiction-like eating, may either persist after surgery or that eating disturbances can develop relatively quickly after surgery. A connection between dumping and disturbed eating would have clinical implications, such as the need for regular monitoring of eating disorder symptoms and, if necessary, early support from mental health professionals [28]. Based on previous research summarized above, the following hypotheses were drawn:

  • 1.

    With respect to the total sample, within-group comparisons will show a reduction in body mass index (BMI) and improvements in HRQoL, anxiety/depressive symptoms, eating disorder symptoms, and addiction-like eating from prior to surgery (t0) to follow-up (t1).

  • 2.

    Between-group comparisons at follow-up (t1) will show lower HRQoL and more anxiety/depressive symptoms in patients with post-surgery dumping syndrome as compared to those without dumping syndrome.

  • 3.

    A multivariate analysis will show that post-surgery dumping syndrome will be associated with type of surgery (i.e., bypass surgery), female gender, lower postoperative HRQoL, and more anxiety/depressive symptoms.

Given the lack of research, no formal hypotheses were drawn regarding between-group differences (i.e., patients with dumping syndrome vs. patients without dumping syndrome) in terms of eating disorder symptoms and addiction-like eating prior to surgery (t0) and at follow-up (t1). Likewise, with respect to multivariate analysis of the predictive value of disturbed or addiction-like eating at follow-up (t1) for post-surgery dumping syndrome, no hypothesis was formulated.

Procedure

Obesity surgery seeking participants were recruited within preoperative bariatric surgery evaluations at three German hospitals (Hannover Medical School [n = 92], Dr. Lubos Kliniken Bogenhausen [n = 92], AMC-WolfartKlinik Graefeling [n = 36]) between April 2019 and December 2020. Inclusion criteria were class 2 or 3 obesity (i.e., BMI ≥35 kg/m2), age 18 years or older, and sufficient German language skills. Exclusion criteria were intellectual impairment, psychosis, and acute suicidal ideations. Baseline (t0) and follow-up (t1) assessments were completely independent from preoperative psychosocial evaluations and pre- as well as postoperative medical care. All data were pseudonymized and participants were assured that assessors would not be included in the routine preoperative evaluations and that data would not be shared with the interdisciplinary obesity treatment teams. For the follow-up assessment (t1), all participants were contacted again via email 6 months after surgery and invited to participate in the assessment that took place between December 2019 and June 2022 (months after surgery, M = 5.99, standard deviation [SD] = 1.39, Mdn = 6.00).

The study protocol met ethical and legal aspects of research involving human subjects in accordance with the Declaration of Helsinki (Institutional Review Board Approval No. 8133_BO_S_2018, Hannover Medical School, Germany). All participants gave written informed consent. The study was preregistered in the German Clinical Trials Register (DRKS00016677).

Participants

The total sample included 220 obesity surgery patients (76% women) with a mean age of 40.99 years (SD = 11.07, Mdn = 41.00, range 18–68). Mean baseline BMI was 49.48 kg/m2 (SD = 6.32, Mdn = 48.93, range 36.93–65.19; 95% class 3 obesity, 5% class 2 obesity). The majority of participants (89%) indicated German as their native language, 72% had completed less than 12 years of school. With respect to employment/occupational status, 52% were employed full time, 18% part time, 10% unemployed, 6% retired, 1% students/trainees/apprentices, and 4% housewives/men. Participants underwent obesity surgery in the following German obesity centers: Dr. Lubos Kliniken Bogenhausen, Munich (n = 92); KRH-Klinikum Nordstadt, Hanover (n = 59); AMC-WolfartKlinik Graefeling (n = 36); DRK-Krankenhaus Clementinenhaus, Hanover (n = 25); and Herzogin Elisabeth Hospital, Brunswick (n = 8). Most patients underwent sleeve gastrectomy (n = 152). Bypass surgery was performed on 68 patients (Roux-en-Y [n = 53], omega loop [n = 14], mono bypass [n = 1]).

Instruments

At baseline (t0) and follow-up (t1), participants were asked to provide demographic information, report height and weight, and to answer the German versions of standardized questionnaires. The German translation of the Sigstad Dumping Score [16] was administered at 6-month follow-up (t1) to identify participants with clinically meaningful post-operative dumping. This clinical diagnostic index has already been used to measure dumping in other studies with obesity surgery patients [15, 19]. The self-report measure captures 16 symptoms that may indicate dumping (see Table 1). Different point values are assigned to the symptoms, which are then added up to a total score (Cronbach’s αt1 = 0.73 in current study). A Sigstad score ≥7 is suggestive of dumping syndrome [16].

Table 1.

Sigstad Dumping Score [16]

SymptomPoint value
Shock +5 
Fainting (syncope), unconsciousness +4 
Desire to lie or sit down +4 
Breathlessness (dyspnea) +3 
Weakness, exhaustion +3 
Sleepiness, drowsiness, apathy, falling asleep +3 
Palpitation +3 
Restlessness +2 
Dizziness +2 
Headaches +1 
Feeling of warmth, sweating, pallor, clammy skin +1 
Nausea +1 
Abdominal fullness, meteorism +1 
Borborygmus +1 
Eructation −1 
Vomiting −4 
SymptomPoint value
Shock +5 
Fainting (syncope), unconsciousness +4 
Desire to lie or sit down +4 
Breathlessness (dyspnea) +3 
Weakness, exhaustion +3 
Sleepiness, drowsiness, apathy, falling asleep +3 
Palpitation +3 
Restlessness +2 
Dizziness +2 
Headaches +1 
Feeling of warmth, sweating, pallor, clammy skin +1 
Nausea +1 
Abdominal fullness, meteorism +1 
Borborygmus +1 
Eructation −1 
Vomiting −4 

HRQoL was measured with the physical component score (PCS: general health perception, physical functioning, physical role functioning, and pain) and the mental component score (MCS: emotional role functioning, mental well-being, negative affectivity, and social functioning) of the German version of the Short-Form Health Survey (SF-12) [29]. Higher PCS/MCS scores indicate higher self-perceived physical/mental quality of life. Cronbach’s α for the components was not calculated due to the differential weighting of the items.

Symptoms of anxiety/depression were measured with the German version of the Hospital Anxiety and Depression Scale (HADS) [30], which contains the two HADS subscales anxiety (HADSAnx, 7 items, Cronbach’s αt0 = 0.69, αt1 = 0.82 in current study) and depression (HADSDepr, 7 items, αt0 = 0.72, αt1 = 0.85 in current study), each ranging from 0 to 21. According to the literature, the cutoff score for each subscale to define clinical relevant anxiety/depression is HADSAnx/Depr ≥8 [30].

Eating disorder symptoms were assessed using the 28-item Eating Disorder Examination Questionnaire (EDE-Q) [31]. Since the original factor structure (i.e., restraint, eating concern, weight concern, shape concern) has been shown to be suboptimal in clinical samples with eating disorders and in obesity surgery candidates [32‒34], the global EDE-Q score including 22 items was used (αt0 = 0.81, αt1 = 0.91 in current study). Higher scores indicate more eating disturbances (cutoff for being at risk for an eating disorder ≥2.3) [35]. In addition, regular binge eating and compensatory behaviors at t1 were explored with EDE-Q items 15–18. Regular binge eating was defined as having ≥4 episodes of overeating with a sense of loss of control at the time (item 15). Items 16–18 were used to examine compensatory behaviors (i.e., vomiting, laxative abuse, compulsive exercising).

The German version of the Yale Food Addiction Scale 2.0 (YFAS 2.0) [36] was administered to assess addiction-like eating. Higher continuous count scores reflecting the number of fulfilled substance use disorder criteria [37] adopted for highly palatable foods suggest more symptoms of food addiction (αt0 = 0.91, αt1 = 0.85 in current study). Meeting at least two criteria and reporting clinically significant impairment/distress was indicative for addiction-like eating [36, 38].

Analyses

Statistical analysis was carried out with SPSS® version 28.0 (IBM Corp., Armonk, NY, USA). Descriptive data are presented as means (M) with SD or absolute numbers (n) and percentages. Within-group changes from t0 to t1 (hypothesis 1) in BMI, HRQoL, anxiety, depression, eating disorder, and food addiction symptoms were explored using paired-sample t test or Chi-square (χ2) test, as appropriate. Patients with and without dumping syndrome were compared on baseline (t0) and follow-up data (t1) (hypothesis 2) including demographic data, BMI, HRQoL, anxiety, depression, eating disorder symptoms, and addiction-like eating using t test for independent groups or Chi-square (χ2) test. A multivariate logistic regression analysis was performed to ascertain the effects of age, gender, type of surgery, HRQoL, and anxiety/depressive symptoms on the likelihood that patients suffer from dumping syndrome (DS = 1, non-DS = 0) (hypothesis 3). In addition, the effects of eating disorder and food addiction symptoms on the presence of dumping syndrome were investigated.

The statistical significance level for all tests was set at α of p < 0.05; all tests were two-tailed. Cohen’s d (t test) and φ or Cramer’s V coefficients (χ2 test) are reported as effect sizes (small: d < 0.5, φ/V < 0.2/0.3; moderate: 0.5 < d < 0.8, 0.25/0.3 < φ/V < 0.7/0.4; large: d > 0.8, φ/V > 0.7/0.4) [39]. For within-group analyses, drepeated measures (dRM), pooled is reported [40].

Changes in BMI and Other Variables from Baseline to Follow-Up within the Total Sample

Within-group changes in BMI, HRQoL, anxiety/depressive symptoms, eating disorder symptoms, and addiction-like eating are shown in Table 2. There were significant changes from baseline to follow-up in all variables. As expected, surgery resulted in significant weight loss, and in improvement in HRQoL and psychopathology, including eating-related symptoms.

Table 2.

Descriptive statistics and within-group comparisons of BMI, HRQoL, eating disorder symptoms, and addiction-like eating from baseline (t0) to 6-month follow-up (t1) in the total sample

nt0, M (SD)t1, M (SD)Within-group comparison
t|dRM, pooled|
BMI 220 49.48 (6.32) 36.52 (5.56) 53.48*** 6.07 
SF-12 PCS 189 31.82 (8.61) 44.16 (8.62) −19.28*** 1.37 
SF-12 MCS 189 40.41 (9.75) 46.19 (8.91) −7.61*** 0.49 
HADSAnx 220 7.77 (3.54) 4.66 (3.76) 12.06*** 0.84 
HADSDepr 220 8.43 (4.01) 2.97 (3.50) 20.23*** 1.29 
EDE-Q global 220 3.03 (0.91) 2.02 (1.11) 13.26*** 0.82 
YFAS 2.0 symptoms 220 4.83 (3.87) 0.94 (1.92) 15.25*** 0.87 
nt0, M (SD)t1, M (SD)Within-group comparison
t|dRM, pooled|
BMI 220 49.48 (6.32) 36.52 (5.56) 53.48*** 6.07 
SF-12 PCS 189 31.82 (8.61) 44.16 (8.62) −19.28*** 1.37 
SF-12 MCS 189 40.41 (9.75) 46.19 (8.91) −7.61*** 0.49 
HADSAnx 220 7.77 (3.54) 4.66 (3.76) 12.06*** 0.84 
HADSDepr 220 8.43 (4.01) 2.97 (3.50) 20.23*** 1.29 
EDE-Q global 220 3.03 (0.91) 2.02 (1.11) 13.26*** 0.82 
YFAS 2.0 symptoms 220 4.83 (3.87) 0.94 (1.92) 15.25*** 0.87 

BMI, body mass index; SF-12, Short-Form Health Survey; PCS, physical component score; MCS, mental component score; HADSAnx, anxiety subscale of the Hospital Anxiety and Depression Scale; HADSDepr, depression subscale of the Hospital Anxiety and Depression Scale; EDE-Q, Eating Disorder Examination Questionnaire; YFAS 2.0, Yale Food Addiction Scale 2.0.

***p < 0.001; dRM, pooled, drepeated measures, pooled.

Post-Surgery Dumping Syndrome

Six months after surgery, the mean Sigstad Dumping Score was 5.18 (SD = 5.73, Mdn = 3.50, range −4 to 26). In the total sample, 72 of 220 patients (33%; group DS) reported a dumping syndrome based on the Sigstad score cutoff and 148 (67%; group non-DS) did not. Concerning the type of surgery, 34 of 68 patients with bypass surgery (50%) had a dumping syndrome as compared to 38 of 152 patients with sleeve gastrectomy (25%; χ(1)2 = 13.34, p < 0.001, φ = 0.25). Most patients with dumping syndrome were women (90%). While 65 of the 167 female patients (39%) suffered from dumping syndrome, only 7 of the 53 male participants (13%) scored above the Sigstad score threshold (χ(1)2  = 12.08, p < 0.001, φ = 0.23).

Comparison of Patients with versus without Post-Surgery Dumping Syndrome

Comparisons of age, BMI, SF-12, HADS, EDE-Q, and YFAS 2.0 mean scores between the DS group and non-DS group at t0 are shown in Table 3. Effect sizes did not indicate meaningful group differences before surgery. Table 4 shows the between-group comparison of post-surgery BMI, SF-12, HADS, EDE-Q, and YFAS 2.0 means. The results suggest lower mental HRQoL and more eating disorder symptoms in patients with as compared to those without dumping syndrome. Effect sizes suggest a large effect for the HADS anxiety subscale score, moderate effects for the HADS global and SF-12 MCS differences, and a small effect for EDE-Q difference.

Table 3.

Descriptive statistics and between-group comparisons of age, BMI, HRQoL, anxiety/depressive symptoms, eating disorder symptoms, and addiction-like eating at baseline (t0) in patients with (DS) or without (non-DS) post-surgery dumping syndrome

Variables at t0DSNon-DStEffect size |dCohen|
nM (SD)nM (SD)
Age 72 36.75 (11.04) 146 42.09 (10.95) 2.11* 0.30 
BMI, kg/m2 72 47.85 (6.99) 148 50.27 (5.83) 2.70* 0.34 
SF-12 PCS 64 30.93 (8.65) 131 32.23 (8.62) 0.98 0.15 
SF-12 MCS 64 38.09 (10.20) 131 41.46 (9.50) 2.27 0.35 
HADSAnx 72 8.74 (3.22) 148 7.30 (3.61) −2.87** 0.41 
HADSDepr 72 9.06 (4.37) 148 8.12 (3.80) −1.63** 0.23 
EDE-Q global 72 3.24 (0.94) 148 2.92 (0.88) −2.45* 0.36 
YFAS 2.0 symptoms 72 4.53 (3.82) 148 4.98 (3.90) 0.81 0.12 
Variables at t0DSNon-DStEffect size |dCohen|
nM (SD)nM (SD)
Age 72 36.75 (11.04) 146 42.09 (10.95) 2.11* 0.30 
BMI, kg/m2 72 47.85 (6.99) 148 50.27 (5.83) 2.70* 0.34 
SF-12 PCS 64 30.93 (8.65) 131 32.23 (8.62) 0.98 0.15 
SF-12 MCS 64 38.09 (10.20) 131 41.46 (9.50) 2.27 0.35 
HADSAnx 72 8.74 (3.22) 148 7.30 (3.61) −2.87** 0.41 
HADSDepr 72 9.06 (4.37) 148 8.12 (3.80) −1.63** 0.23 
EDE-Q global 72 3.24 (0.94) 148 2.92 (0.88) −2.45* 0.36 
YFAS 2.0 symptoms 72 4.53 (3.82) 148 4.98 (3.90) 0.81 0.12 

BMI, body mass index; SF-12, Short-Form Health Survey; PCS, physical component score; MCS, mental component score; HADSAnx, anxiety subscale of the Hospital Anxiety and Depression Scale; HADSDepr, depression subscale of the Hospital Anxiety and Depression Scale; EDE-Q, Eating Disorder Examination Questionnaire; YFAS 2.0, Yale Food Addiction Scale 2.0.

*p < 0.05.

**p < 0.01.

Table 4.

Descriptive statistics and between-group comparisons of BMI, HRQoL, anxiety/depressive symptoms, eating disorder symptoms, and addiction-like eating 6 months after surgery (t1) between patients with (DS) and without (non-DS) post-surgery dumping syndrome

Post-surgery variables (t1)DSNon-DStEffect size |dCohen|
nM (SD)nM (SD)
BMI, kg/m2 72 35.25 (6.10) 148 37.13 (5.19) 2.38 0.34 
Change in BMI 72 12.60 (3.72) 148 13.14 (3.53) 1.05 0.15 
SF-12 PCS 72 43.13 (9.45) 142 44.83 (7.91) 1.39 0.20 
SF-12 MCS 72 43.32 (9.82) 142 47.71 (8.16) 3.47*** 0.50 
HADSAnx 72 6.64 (4.23) 148 3.70 (3.09) −5.83*** 0.84 
HADSDepr 72 3.90 (4.24) 148 2.51 (2.99) −2.80* 0.40 
HADS global 72 10.54 (8.05) 148 6.22 (5.51) −4.66*** 0.67 
EDE-Q global 72 2.31 (1.19) 148 1.88 (1.05) −2.76* 0.39 
YFAS 2.0 symptoms 72 1.19 (2.26) 148 0.82 (1.72) −1.36 0.19 
Post-surgery variables (t1)DSNon-DStEffect size |dCohen|
nM (SD)nM (SD)
BMI, kg/m2 72 35.25 (6.10) 148 37.13 (5.19) 2.38 0.34 
Change in BMI 72 12.60 (3.72) 148 13.14 (3.53) 1.05 0.15 
SF-12 PCS 72 43.13 (9.45) 142 44.83 (7.91) 1.39 0.20 
SF-12 MCS 72 43.32 (9.82) 142 47.71 (8.16) 3.47*** 0.50 
HADSAnx 72 6.64 (4.23) 148 3.70 (3.09) −5.83*** 0.84 
HADSDepr 72 3.90 (4.24) 148 2.51 (2.99) −2.80* 0.40 
HADS global 72 10.54 (8.05) 148 6.22 (5.51) −4.66*** 0.67 
EDE-Q global 72 2.31 (1.19) 148 1.88 (1.05) −2.76* 0.39 
YFAS 2.0 symptoms 72 1.19 (2.26) 148 0.82 (1.72) −1.36 0.19 

BMI, body mass index; SF-12, Short-Form Health Survey; PCS, physical component score; MCS, mental component score; HADSAnx, anxiety subscale of the Hospital Anxiety and Depression Scale; HADSDepr, depression subscale of the Hospital Anxiety and Depression Scale; EDE-Q, Eating Disorder Examination Questionnaire; YFAS 2.0, Yale Food Addiction Scale 2.0.

*p < 0.01;

***p < 0.001.

Based on HADS threshold for probable anxiety disorder, patients with post-surgery dumping syndrome were more often at risk for an anxiety disorder at t0 (54% vs. 39%, χ(1)2  = 4.41, p = 0.036, φ = 0.14) and t1 (29% vs. 7%, χ(1)2  = 18.41, p < 0.001, φ = 0.29) than those without dumping syndrome. No difference between individuals with and without dumping syndrome was found with regard to probable depressive disorder at t0 (54% vs. 51%, χ(1)2  = 0.24, p = 0.627, φ = 0.03). In contrast, individuals with dumping syndrome were more often classified as having a post-surgery depressive disorder than individuals without dumping (14% vs. 5%, χ(1)2  = 5.70, p = 0.017, φ = 0.16), whereas the magnitude of the effect was small. Based on the EDE-Q threshold, the rate of patients at risk for an eating disorder at t0 in the DS group (82%) did not differ from the non-DS group (76%, χ(1)2  = 0.89, p = 0.346, φ = 0.06). In terms of regular binge eating, at t0 the groups did not differ either (36% vs. 33%, χ(1)2  = 0.24, p = 0.627, φ = 0.03), but effect sizes indicate small group differences at t1 with 46% of the DS group and 30% of the non-DS group being at risk for an eating disorder (χ(1)2  = 5.52, p = 0.019, φ = 0.16). In addition, regular post-surgery binge eating was more often reported in the DS than in the non-DS group (15% vs. 5%, χ(1)2  = 5.29, p = 0.021, φ = 0.17). No group differences were found with respect to compensatory behaviors (i.e., vomiting, laxative abuse, compulsive exercising) at t0 or t1. Considering the YFAS 2.0 cutoff, 39% of the DS and 42% of the non-DS group were at risk for food addiction at baseline (t0) (χ(1)2  = 0.18, p = 0.671, φ = 0.03), while 7% of the DS and 4% of the non-DS group were at risk at 6-month follow-up (t0) (χ(1)2  = 0.85, p = 0.356, φ = 0.06).

Association of Dumping Syndrome with Other Post-Surgery Variables

Because of the high correlation between the HADS anxiety and HADS depression subscales (r = 0.73; p < 0.001), a HADS global score was built by adding up the anxiety and depression subscale scores. The HADS global score was highly correlated with the SF-12 MCS (r = −0.73) but not with the SF-12 PCS (r = −0.19). Considering the strong correlation between the HADS global score and the SF-12 mental health score and the difference in effect sizes shown in Table 4, we decided to enter only the HADS global score (but not the SF-12 mental health score) as predictor. All other variables were at most moderately correlated (r ranging from 0.13 to 0.45). Table 5 shows the final results (particularly steps 4 and 5) of the multivariate logistic regression analysis with post-surgery dumping syndrome (N = 201; DS = 1, non-DS = 0) as dependent variable and age and gender (step 1), type of surgery (step 2), physical HRQoL (step 3), general psychopathology (i.e., HADS global score; step 4), and eating disorder/food addiction symptoms (step 5) as independent variables.

Table 5.

Summary of logistic regression analysis (steps 3 and 4) for exploring the effects of age, gender, type of surgery, post-surgery physical HRQoL, post-surgery anxiety/depressive symptoms, post-surgery eating disorder symptoms, and addiction-like eating on dumping syndrome (DS = 1, n = 71; non-DS = 0, n = 130)

nBSEWalddfp valueOdds ratio95% CI for odds ratio
LLUL
Step 4 
 Age 201 −0.026 0.016 2.723 0.099 0.974 0.945 1.005 
 Gender 
  Male 47 (ref) (ref) (ref) (ref) (ref) (ref) (ref) (ref) 
  Female 154 1.422 0.486 8.551 0.003 4.146 1.598 10.754 
 Surgery 
  Sleeve 135 (ref) (ref) (ref) (ref) (ref) (ref) (ref) (ref) 
  Bypass 66 1.196 0.351 11.587 <0.001 3.306 1.661 6.580 
 SF-12 PCS 201 −0.023 0.021 1.243 0.265 0.977 0.938 1.018 
 HADS global 201 0.096 0.027 12.617 <0.001 1.101 1.044 1.161 
Step 5 
 Age 201 −0.022 0.016 1.913 0.165 0.978 0.947 1.009 
 Gender 
  Male 47 (ref) (ref) (ref) (ref) (ref) (ref) (ref) (ref) 
  Female 154 1.574 0.500 9.905 0.002 4.826 1.811 12.862 
 Surgery 
  Sleeve 135 (ref) (ref) (ref) (ref) (ref) (ref) (ref) (ref) 
  Bypass 66 1.191 0.360 10.929 <0.001 3.289 1.624 6.662 
 SF-12 PCS 201 −0.026 0.021 1.503 0.220 0.974 0.934 1.016 
 HADS global 201 0.100 0.031 10.407 0.001 1.106 1.040 1.175 
 EDE-Q global 201 0.128 0.178 0.520 0.471 1.137 0.802 1.611 
 Regular binge eating1 
  No 186 (ref) (ref) (ref) (ref) (ref) (ref) (ref) (ref) 
  Yes 15 1.744 0.813 4.605 0.032 5.721 1.163 28.137 
 YFAS 2.0 symptoms 201 −0.224 0.120 3.496 0.062 0.800 0.633 1.011 
nBSEWalddfp valueOdds ratio95% CI for odds ratio
LLUL
Step 4 
 Age 201 −0.026 0.016 2.723 0.099 0.974 0.945 1.005 
 Gender 
  Male 47 (ref) (ref) (ref) (ref) (ref) (ref) (ref) (ref) 
  Female 154 1.422 0.486 8.551 0.003 4.146 1.598 10.754 
 Surgery 
  Sleeve 135 (ref) (ref) (ref) (ref) (ref) (ref) (ref) (ref) 
  Bypass 66 1.196 0.351 11.587 <0.001 3.306 1.661 6.580 
 SF-12 PCS 201 −0.023 0.021 1.243 0.265 0.977 0.938 1.018 
 HADS global 201 0.096 0.027 12.617 <0.001 1.101 1.044 1.161 
Step 5 
 Age 201 −0.022 0.016 1.913 0.165 0.978 0.947 1.009 
 Gender 
  Male 47 (ref) (ref) (ref) (ref) (ref) (ref) (ref) (ref) 
  Female 154 1.574 0.500 9.905 0.002 4.826 1.811 12.862 
 Surgery 
  Sleeve 135 (ref) (ref) (ref) (ref) (ref) (ref) (ref) (ref) 
  Bypass 66 1.191 0.360 10.929 <0.001 3.289 1.624 6.662 
 SF-12 PCS 201 −0.026 0.021 1.503 0.220 0.974 0.934 1.016 
 HADS global 201 0.100 0.031 10.407 0.001 1.106 1.040 1.175 
 EDE-Q global 201 0.128 0.178 0.520 0.471 1.137 0.802 1.611 
 Regular binge eating1 
  No 186 (ref) (ref) (ref) (ref) (ref) (ref) (ref) (ref) 
  Yes 15 1.744 0.813 4.605 0.032 5.721 1.163 28.137 
 YFAS 2.0 symptoms 201 −0.224 0.120 3.496 0.062 0.800 0.633 1.011 

CI, confidence interval; LL, lower limit; UL, upper limit; SF-12, Short-Form Health Survey; PCS, physical component score; HADS, Hospital Anxiety and Depression Scale; EDE-Q, Eating Disorder Examination Questionnaire; YFAS 2.0, Yale Food Addiction Scale 2.0.

1Regular binge eating based on EDE-Q item 15.

The logistic regression model was statistically significant (χ2 = 52.24, df = 8, p < 0.001, Nagelkerke’s R2 = 0.315). The model indicates that women as compared to men (OR = 4.83, 95% confidence interval [CI] [1.81, 12.86]) and patients after bypass surgery as compared to sleeve gastrectomy (OR = 3.29, 95% CI [1.62, 6.66]) were more likely to report post-surgery dumping syndrome. Furthermore, more post-surgery anxiety/depressive symptoms (OR = 1.11, 95% CI [1.04, 1.17]) and regular binge eating were associated with an increase in the likelihood of dumping syndrome. With respect to binge eating, the wide CI indicates a rather imprecise estimate (OR = 5.72, 95% CI [1.16, 28.14]).

The findings of the present study support our hypothesis 1 and match previous findings [5, 7‒11] regarding the reduction in BMI and improvements in HRQoL, anxiety/depressive symptoms, eating disturbances, and addiction-like eating from baseline to follow-up (see Table 2). In the present sample, the prevalence of dumping syndrome after obesity surgery as measured with the Sigstad Dumping Score was 33%, which is in line with the literature, where a range of 20–40% has been reported [12‒14, 17‒19, 41]. Partially supporting our hypothesis 2, patients with dumping syndrome showed more symptoms of post-surgery anxiety and depression, and lower post-surgery mental but not physical HRQoL than those without dumping syndrome on bivariate level (see Table 4). The findings on reduced mental HRQoL in patients with dumping syndrome are in accordance with previous results concerning the negative impact of dumping syndrome on patients’ HRQoL following obesity surgery [15, 22, 25, 26]. More severe dumping may worsen mental HRQoL due to the unpleasant, emotionally distressing dumping symptoms and their interference with daily functioning. This assumption is also supported by the high correlation between the SF-12 MCS and the HADS global score. The overlap is not surprising given that the SF-12 mental score includes questions referring to mental well-being and negative affectivity, and the HADS consists of items assessing anxiety and depression. In contrast to previous studies [12, 25], the group difference in physical HRQoL did not reach statistical significance. In a study with Chinese patients who underwent primary laparoscopy sleeve gastrectomy (median time between surgery and follow-up was 25 months), individuals with symptoms suggestive of dumping syndrome (46%) compared to those without dumping syndrome (54%) reported worse HRQoL in only 4 (i.e., general health, vitality, emotional role, mental health) out of 8 SF-36 subdomains [41]. No group differences were found with regard to the following SF-36 subdomains: physical function, bodily pain, role function, and social function [41]. Our findings regarding a lack of group differences in physical HRQoL seem to be similar to the lack of group differences in the Chinese study, whereby the methodological differences between the two studies should be taken into account. Yang et al. [41] used the Dumping Symptom Rating Scale (DSRS) [42] to assess dumping syndrome. Based on the DSRS, none of their patients with dumping syndrome had moderate or severe dumping, which might explain their findings regarding physical HRQoL. In our sample, the DS group was defined as having severe dumping symptoms according to the Sigstad cutoff score [16]. Another explanation for the lack of group differences in physical HRQoL in our sample could be the relatively short follow-up period. It is possible that the markedly improved physical HRQoL 6 months after surgery was so strong in both the DS and non-DS group that no significant group differences emerged. The high SF-12 PCS pre-post effect size (see Table 2) supports this assumption. It is, however, questionable whether this effect will last in the longer term.

Accordingly, the hypothesis 3 was not fully supported either (see regression analysis [Table 5], step 4). While female gender, bypass surgery, and anxiety/depression were associated with dumping syndrome, this was not the case for physical HRQoL. The connection between dumping syndrome and female gender [17, 19, 23] is difficult to explain and needs further investigation. The high proportion of women in the present sample (76%) may have contributed to the result, indicating a selection bias. With regard to the type of surgery, our results are consistent with previous research showing that dumping syndrome is especially common following bypass surgery [12, 15, 21‒24]. Notably, one quarter of patients who had undergone sleeve gastrectomy reported dumping syndrome either. This supports previous findings showing that dumping syndrome after sleeve gastrectomy is not entirely rare [24, 41]. As mentioned above, the association between dumping syndrome and a higher level of general psychopathology (i.e., anxiety/depressive symptoms) resembles previous findings [25]. The result should not be over-interpreted, particularly in terms of depression. If the HADS thresholds and the effect sizes of the group comparisons shown in Table 4 are considered, the group effect was only small for depression and moderate for anxiety disorder. Severe dumping may trigger (anticipatory) anxiety symptoms and/or individuals with a higher level of anxiety may be particularly sensitive to dumping symptoms. However, the cross-sectional design of the post-surgery comparison prevents any causal interpretation. The direction of the relationship between dumping syndrome and anxiety should be addressed in further research.

The comparison of post-surgery eating disorder symptoms measured with the EDE-Q global score of patients with dumping syndrome compared to those without dumping syndrome indicate lower symptom burden in the non-DS group (see Table 4). Almost half of the patients with dumping syndrome but only one-third of the patients without dumping syndrome were at risk for an eating disorder based on EDE-Q threshold. However, the magnitude of the effect was rather small. The same is true for post-surgery binge eating, which was reported by 15% of the DS group and 5% of the non-DS group. Considering the results of the regression analysis (see Table 5), it appears that patients with post-surgery dumping syndrome are more likely to have regular binge eating as compared to those without dumping syndrome. This outcome seems plausible given that binge eating is characterized by loss of control over food intake, which can lead to violation of dietary recommendations (e.g., intake of larger amounts of sugary foods or beverages), resulting in dumping symptoms. Loss-of-control eating was also related to dumping in a study by Kalarchian et al. [27]. Nevertheless, our result should be interpreted with caution. The high odds ratio together with the wide CI may be related to the binary type of the variable (binge eating yes/no) and the relatively small post-surgery binge eating frequency in the present sample. Therefore, the link between post-surgery binge eating and dumping syndrome should always be considered but not overrated in clinical routine. In both groups, post-surgery addiction-like eating was rarely reported and does not seem to play a significant role with regard to the occurrence of dumping. This is in accordance with past research showing a substantial decrease in food addiction symptoms 6–24 months after obesity surgery [10, 11, 43, 44].

The present investigation has some shortcomings. The main limitation refers to the use of questionnaires instead of clinical interviews to assess psychosocial variables. Also, no objective tests were used to confirm the presence of dumping syndrome or to consider other reasons for the self-reported somatic symptoms (e.g., postoperative strictures, somatic comorbidities). This approach might have resulted in diagnostic errors. In addition, no differentiation was made between early and late dumping symptoms. The follow-up period was relatively short. Moreover, statistical power was limited to investigate connections between dumping and less common post-surgery symptoms such as binge eating or addiction-like eating behavior.

Overall, the current study failed to show a close relationship between the presence of self-reported dumping and post-surgery eating disorder symptoms or addiction-like eating. On the one hand, this could be related to the decrease of these symptoms after surgery. In the total sample, as expected, eating disorder and food addiction symptoms occurred much less frequently at follow-up compared to before surgery. On the other hand, our results can be interpreted as indicating that post-surgery dumping is a predominantly somatic problem that is related to anxiety and depressive symptoms and that impacts patients’ HRQoL. Further studies with longer follow-up periods should make use of clinical interviews to assess psychosocial variables and objective measures to diagnose dumping in addition to standardized self-ratings.

The present finding have clinical implications for early post-operative support, which should address not only physical but also mental problems. In view of the link between symptoms indicative for dumping syndrome and psychopathology, dietary modifications could be combined with psychosocial assessments and, if necessary, also with psychotherapeutic and/or psychopharmacological interventions. This underlines the demand for the integration of early psychosocial evaluation and support into multidisciplinary management [28] and the consequent inclusion of mental health professionals not only in preoperative but also postoperative care.

We wish to thank Dr. Christina Holzapfel (Institute for Nutritional Medicine, School of Medicine, University Hospital Klinikum rechts der Isar, Technical University of Munich, Munich, Germany) and Katja Tilk (Department of Psychosomatic Medicine and Psychotherapy, Hannover Medical School, Hanover, Germany) for their support in organizing this study.

The study protocol met ethical and legal aspects of research involving human subjects in accordance with the Declaration of Helsinki (Institutional Review Board Approval No. 8133_BO_S_2018, Hannover Medical School, Germany). Written informed consent was obtained from all subjects involved in the study. The study was preregistered in the German Clinical Trials Register (DRKS00016677).

The authors declare no conflict of interest.

This research received no external funding.

Conceptualization: A.M., S.E., and M.P.; methodology and formal analysis: A.M., N.M.L., and S.E.; validation: A.M., N.M.L., and M.P.; investigation, data curation, and project administration: S.E. and M.P.; resources: M.dZ., T.P.H., G.M., J.M., R.W., and H.K.; writing – original draft preparation: A.M. and N.M.L.; writing – review and editing: A.M., S.E., N.M.L., M.P., T.P.H., J.W.M., G.M., R.W., H.K., and M.dZ.; visualization: A.M.; and supervision: M.dZ. All authors have read and agreed to the published version of the manuscript.

The data presented in this study are openly available at https://doi.org/10.26068/mhhrpm/20230522-000.

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