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Keywords:

  • Bariatric surgery;
  • food intolerances;
  • nutritional deficiencies;
  • obesity

Summary

  1. Top of page
  2. Summary
  3. Introduction
  4. Methods
  5. Findings
  6. Discussion
  7. Conclusion
  8. Conflict of Interest Statement
  9. Acknowledgements
  10. References

Bariatric surgery is the most effective means of achieving sustainable weight loss for the morbidly obese but resultant gastrointestinal functional changes and altered diet may lead to a number of eating and nutritional problems. This audit was conducted to evaluate Guernsey outcomes in relation to UK national standards and to determine the adequacy of current dietetic provision. A postal questionnaire was sent to 177 patients. Sixty-eight responded (48 gastric bypass, 15 banding and five other procedures). Mean body mass index preoperatively was 44.2 (five had body mass index <35). Five respondents (7%) had received preoperative and 26 post-operative dietary advice. Only 12 (18%) received any dietetic follow-up. Only one patient had any psychological support. Mean maximal weight loss and regain was 42.7 kg and 4.5 kg, respectively. Micronutrient supplementation and monitoring was variable. Deficiencies of B12 (44%), iron (25%), vitamin D (10.2%) and folate (6.2%) were recorded. Problems with food intolerances were common and often protracted. The majority of respondents expressed satisfaction with the procedure, but many recognized that it had not solved their food-related issues. There was dissatisfaction with dietetic intervention. Overall, current treatment was shown to fall short of UK standards. A number of recommendations have been made to improve future outcomes, including re-audit and improved dietetic service provision.


Introduction

  1. Top of page
  2. Summary
  3. Introduction
  4. Methods
  5. Findings
  6. Discussion
  7. Conclusion
  8. Conflict of Interest Statement
  9. Acknowledgements
  10. References

Bariatric surgery has increased in prevalence over the last decade as evidence mounts regarding its effectiveness in reducing cholesterol levels, hyperglycaemia, blood pressure and premature death from cancer and myocardial infarction (1). It is currently recognized as the most effective intervention for morbid obesity but as well as the potential for early surgical complications, such as cholecystitis, intestinal obstruction and anastomotic strictures(2), other problems, such as weight regain, food intolerances, nausea and vomiting (often related to dietary non-compliance), and/or nutritional deficits may occur (2–4).

Deficiencies are especially common after bypass or pancreatic biliary diversion procedures, because of a combination of reduced intake, changed diet and malabsorption (5). Studies suggest around 60% of post-operative patients may develop deficiencies in B12, 50% may experience iron and or vitamin D deficits, almost 40% may be folate-deficient and around 10% may have suboptimal calcium and/or vitamin A status (6). Iron (and B12) deficiency in this population is recognized to be associated with long-standing intolerance of iron-rich foods, particularly meat, as well as to malabsorption caused by low gastric acid levels (6). Preoperative marginal vitamin D status (caused by poor diet and lack of sunlight exposure in housebound obese subjects) may also be exacerbated post-operatively by inadequate diet, malabsorption and inactivity (7), leading to overt deficiencies. Regular blood tests and clinical review are important to identify signs of deficiency. Clinical signs, such as flaky nails, dry skin and hair loss, may also indicate poor micronutrient status, e.g. zinc. Nutritional deficits can be observed even among bypass patients prescribed a general multivitamin/mineral preparation (8,9) and some units recommend high-dose prophylactic supplementation to all bypass and pancreatic biliary diversion patients (10).

Reduced gastric capacity, malabsorption, reduced transit time and the psychological drivers that led to weight gain preoperatively may also lead to problematic eating behaviour post-operatively (11). Provision of eating behaviour guidelines, regarding restricted portion size, chewing food slowly, eating and drinking separately and adequate fluid intake, is important (12). It is also recognized that regular support and advice on avoidance of fatty and sugary foods, adequate protein intake (from well-tolerated sources) appropriate supplementation, weight loss targets and advice on eating out are vital to optimize outcomes and minimize post-operative nutritional and dietary problems (10–12).

The National Institute for Clinical Excellence (NICE) guidelines (13) set out a clear framework for the safe and effective management of bariatric surgery patients in the UK. They recommend consideration of surgery in those with a body mass index (BMI) >40 (or >35 in the presence of significant comorbidity) only after all other non-surgical treatment options have been tried and failed (and in those with a BMI > 50 as first line treatment). The guidelines state that all patients should be adequately assessed preoperatively with regard to the relative risks and benefits of surgery, any psychological or clinical factors that may impact on outcomes (including specialist assessment for eating disorders). They further recommend that specialist dietetic care and psychological support is included within a multidisciplinary support team.

Guernsey (with a population of about 65 000) lies in the Channel Isles. Although its Health and Social Services Department stands outside the jurisdiction of the UK National Health Service, it refers to UK standards and guidelines to inform local practice. Bariatric surgery has been performed there since 2001, leading to a now sizeable post-operative population. At present the surgery is classified as cosmetic and carried out as a private procedure but utilizing Health and Social Services Department facilities and resources.

A single dietetic session is included within the total private package charge but in practice few patients are referred to see a dietitian either before or after surgery. However, a number of patients have been referred to the department post-operatively with complications, including liver cirrhosis, a newly emergent eating disorder (preoperative BMI 34), binge eating and drinking and severe intolerances leading to malnutrition and the prescription of nutritional sip feeds. In light of the research evidence, local experience and a rapidly expanding population of nutritionally high-risk individuals this audit was undertaken to provide baseline data for ongoing audit and to inform dietetic service provision planning.

Methods

  1. Top of page
  2. Summary
  3. Introduction
  4. Methods
  5. Findings
  6. Discussion
  7. Conclusion
  8. Conflict of Interest Statement
  9. Acknowledgements
  10. References

The aim of this audit was to evaluate local nutritional and dietary outcomes following bariatric surgery, particularly to ascertain the extent to which NICE guidelines were being followed. It also sought to establish outcomes in relation to weight loss and maintenance, nutritional adequacy, use of nutritional supplements and quality of life issues in relation to eating patterns, food tolerance and social eating.

Healthcare information analysts identified 177 individuals who had undergone bariatric surgery in Guernsey (as either a primary or secondary procedure) since the procedure was first performed in 2001, until November 2008. These comprised the audit population. As patient experiences and diet histories were required, a postal questionnaire was selected as the least invasive means of data collection. After piloting, this was sent to all patients with a covering letter explaining the purpose of the audit (to improve dietetic care) and advising that if any individuals preferred to remain anonymous they should omit their names. Prepaid stamped addressed envelopes were included for ease of return.

Findings

  1. Top of page
  2. Summary
  3. Introduction
  4. Methods
  5. Findings
  6. Discussion
  7. Conclusion
  8. Conflict of Interest Statement
  9. Acknowledgements
  10. References

Demographics

177 patients (24 male and 153 female) were identified as having undergone bariatric surgery between 2001 and November 2008 (see Table 1). Of 177 questionnaires posted, 68 were completed and returned (38%). Of these seven (10%) were male. The average age at operation was 44 years (range 22–64 years). Mean duration since surgery was 2.4 years (range 2 months–5 years).

Table 1.  General characteristics and pre- and post-operative monitoring cf NICE standards
CriterionDataNICE standard and whether met
  1. BMI, body mass index; f, female; m, male; NA, not applicable; NICE, National Institute for Clinical Excellence.

Gender7 (10%)m, 61 (90%)fNA
Age at operation, mean (range)44 (22–64)YES
Time since operation, mean (range)2.4 years ( 2 months–5 years)NA
ProcedureA band 15 (22%) 
B bypass 48 (71%)NA
C other 5 (7%) 
Preoperative BMI, mean (range)44.2 (33–>60)>40 or
BMI 35–<40 no comorbidities9>35 if comorbidities
BMI < 355NO
Previous dietetic input21 (35%) 10 RD recordsNO
Preoperative dietetic assessment5 (7%) 3 RD recordsNO
Preoperative psych assessment1 (1.5%)NO
Post-operative dietetic advice26 (38%) 29 RD recordsNO
Dietetic follow-up12 (18%) 14 RD recordsNO
Psych follow-up1 (1.5%)NO

Preoperative body mass index

The NICE guidelines recommend that all individuals undergoing bariatric surgery have a BMI ≥ 40 kg m−1 (or ≥35 in the presence of serious comorbidities).

Mean BMI preoperatively was 44.2 (range 33–>60). Twenty-nine patients recalled no preoperative comorbidity, of those who did, 12 were diabetic, nine had high blood pressure, eight had back or joint pain and nine reported other problems, including reflux, failed hernia repair, fibromyalgia and depression. Twenty-two (32%) patients had a BMI 35–<40 prior to surgery (see Table 1). Of these nine reported no comorbidity. A further five respondents had a preoperative BMI of <35 (the lowest BMI was 31).

Initial procedure, revisions and surgical complications

Fifteen (22%) patients had initially undergone a gastric band procedure, 48 (71%) had a bypass (including one who first had a band) and five (7%) had undergone other bariatric procedures (see Table 1). Thirteen (87%) reported that they required tightening of their gastric bands and one of these then needed a further readjustment to loosen an over-tight band. Three (20%) respondents progressed from a band to bypass and two (4.2%) bypass patients required revisional surgery. In terms of complications, three (4.4%) respondents reported that they developed strictures, three required cholecystectomies, three developed kidney stones, three developed abscesses, one reported a hernia and one experienced a gastrointestinal bleed post-operatively.

Dietetic input

The NICE guidelines recommend:

  • • 
    Dietary change as advised by a qualified dietitian, comprises one of the appropriate non-surgical methods of treatment for obesity that should be fully explored prior to considering surgery.
  • • 
    Preoperative dietetic assessment and support in preparation for bariatric surgery is also a key element of the intensive specialist multidisciplinary team involvement recommended by NICE.
  • • 
    Post-operatively the provision of regular specialist dietetic monitoring is identified in the guidelines as an essential component of care.

Twenty-one (35%) of the respondents in this audit reported seeing a dietitian at some time in the past but only five (7%) reported that they had seen a dietitian prior to making a decision regarding surgery or preoperatively. Only 26 (38%) recalled being visited by a dietitian on the ward prior to discharge and only 12 (18%) recalled any further dietetic follow-up. Only one respondent reported seeing a psychologist pre- and post-operatively (at their own request and for other issues). A cross-check with dietetic records suggested that only 10 patients had expert advice before considering surgery (but records before 2002 may have been destroyed). Dietetic records further indicated that three patients were given appropriate preoperative assessments, 29 received at least one visit in hospital post-operatively and 14 had follow-up – sometimes long-term and often for dietary complications/intolerances.

Weight loss

The NICE guidelines do not specify the rate of weight loss but advise that dietetic monitoring should give guidance and support regarding long-term weight loss and maintenance.

Mean weight loss was 42.7 kg (SD 15.09), range 15–83 kg. Mean weight regain was 4.5 kg (SD 5.71), range 0–24 kg (see Fig. 1). Percentage weight losses averaged 32.7% (SD 10.42), range 14.8%–56%. Percentage weight regain averaged 9.9% (SD 13.40), range 0%–71% of weight lost (Fig. 2). Analysed according to length of time post-operatively, mean losses were 32.65% (SD 10.42), 39.3% (SD 7.57), 36.1% (SD 7.12) for the <2 years post-operative (n = 25), 2–5 years post-operative (n = 35) and the >5 year post-operative (n = 8) subgroups, respectively. Percentage weight regains were on average 5.4% (SD 8.23), 12.2% (SD 9.02) and 26.4% (SD 25.54) in the <2 years, 2–5 years and >5 years subgroups, respectively. Mean overall weight losses equated to 30.1% (range 14.8%–55.4%) in the <2 years, 32.9% (range 23.9%–50.3%) in the 2–5 years and 27.4% (range 6.8%–49%) in the >5 years groups.

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Figure 1. Long-term percentage weight loss following bariatric surgery.

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Figure 2. Comparative weight loss – banding cf. bypass.

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Nutritional supplements

The NICE guidelines recommend that individualized nutritional supplementation is planned and monitored by a specialist dietitian.

Twelve (17.6%) respondents said they took no micronutrient supplements (nine of these had gastric bands, one a sleeve gastrectomy, one stapling and one bypass). Forty-nine took a multivitamin and mineral (complete one a day) preparation (including 45 or 94% of bypass patients); 30 reported taking calcium supplements (including 29 or 60% of bypass patients). Twelve (11 or 23% of bypass patients) reported taking vitamin D; 16 (15 or 31% of bypass patients) were taking iron; 30 (29 or 60.4% bypass group) recalled having B12 injections; three took folate, two took zinc and one person also took selenium and vitamin A (see Table 2).

Table 2.  Nutritional and dietary outcomes
Micronutrient supplements10 (67%) band 2 (4.2%) bypass none
4 (26%) band 45 (93%) bypass vitamin/mineral
1 (6%) band 29 (60.4%) bypass calcium
1 (5%) band 11 (23%) bypass vitamin D
1 (6%) band 15 (31%) bypass iron
1 (6%) 29 (60.4%) bypass B12
3 (6%) bypass folate
2 (4%) bypass zinc
1 selenium and vitamin A
Known nutritional deficits1 (6%) band 20 (42%) bypass B12
12 (25%) bypass iron
3 (6.2%) bypass folate
5 (10.4%) bypass vitamin D
4 (8.3%) bypass osteoporotic
Hair loss41 (60%)
Flaky nails24 (35%)
Dry skin14 (20.5%)
Dietary problems post-operativeDumping 23 (33.8%)
Diarrhoea 15 (22%)
Nausea 12 (17.6%)
Food intolerances post-operativeMeat 17 (25%)
Bread 13 (19%)
Rice 8 (11.8%)
Pasta 5 (7.3%)
Egg 3 (4.4%)
Food intolerances after 2 years17 (60.7%) n = 28
Meat 9 (32.1%)
Rice 4 (14.2%)
Pasta 3 (10.7%)
Emotional aspects28 (41%) still comfort eating
4 (5.9%) >alcohol
3 (4.4%) >smoking
4 (5.9%) >depressed
Cravings32 (47%)
Satisfaction with surgery50 (75%) satisfied
17 (25%) not solved problems
Satisfaction with dietitians46 (68%) wanted more advice
9 (35%) found info given inadequate

Thirty-two (47.1%) reported no known nutritional deficits, one gastric band patient and 20 bypass patients (42%) had experienced low B12 levels (see Table 2). Other deficiencies identified in bypass patients included 12 (25%) who recalled being iron-deficient, three (6.2%) were low in folate, five (10.2%) had been found to have low circulating vitamin D levels and four (8.3%) were clinically diagnosed to be osteoporotic. One respondent also reported eye problems that resolved upon taking high-dose vitamin A supplements. Other (possibly) nutrition-related problems included 41 who had experienced hair loss, 24 who reported flaky nails and 14 had experienced dry skin post-operatively.

Food intake post-operatively

The NICE guidelines recommend that dietetic support should encompass the provision of dietary advice appropriate to the procedure (and outcomes).

Forty-one (60.2%) respondents had experienced some problems tolerating food in the early post-operative period (see Table 2). These problems comprised dumping in 23 (33.8%), diarrhoea in 15 (22%), nausea in 12 (17.6%) and intolerance to specific foods, including meat 17 (25%), bread 13 (19%), rice 8 (11.8%), pasta 5 (7.3%) and egg 3 (4.4%). Of those who were more than 2 years post-operative (28 respondents) 17 (60.7%) still had problems tolerating specific foods. Nine (32.1%) reported ongoing problems with meat and only one respondent felt able to eat meat as often as before the operation. Four (14.2) still had problems with rice, three (10.7%) with pasta, and other problem foods included bread, fish, cheese and tomatoes. Dry, fatty or sweet foods were also problematic for some.

Of all respondents 28 (41%) reported that they still tended to comfort eat to a greater or lesser extent and 32 (47%) still experienced strong food cravings. Four (5.9%) reported drinking more alcohol since the operation, three (4.4%) said they now smoked more and four said they (5.8%) were more depressed. Thirty-four (50%) said they exercised more since the operation, 19 (27.9%) said they did not exercise at all and 14 (20.5%) said their exercise levels were the same as previously.

Satisfaction with service

The NICE guidelines recommend long-term support and monitoring by specialist dietitians.

Fifty (73.5%) of respondents regarded themselves as satisfied overall with the outcome of the surgery and some took the opportunity to comment that it had been life-changing (see Table 2). However, 17 (25%) felt the surgery had not really solved their problems. Forty-six (67.6%) would have appreciated more dietetic advice and support. Nine (35%) of those who received dietetic advice in hospital commented that it was inadequate, unhelpful and/or only focused on the immediate post-operative adaptive phase. Two (7.7%) felt that the dietitians had inadequate knowledge of the procedure. One woman felt there was a general perception among patients that the dietetic department disapproved of the procedure.

Discussion

  1. Top of page
  2. Summary
  3. Introduction
  4. Methods
  5. Findings
  6. Discussion
  7. Conclusion
  8. Conflict of Interest Statement
  9. Acknowledgements
  10. References

Unfortunately there was a low response rate to this audit, with just under 40% of questionnaires returned. In an audit of this type this may be expected to result in a positive bias, with probable under-representation of poor outcomes. This should be taken into account when interpreting the data. A further limitation is that the questionnaire relied on retrospective recall. Accuracy of recall may be particularly difficult where a substantial amount of time has lapsed since the operation and this may further limit the reliability of the data. However, cross-referencing with dietetic records, where appropriate, indicated reasonable agreement. Despite these limitations, these data give service user feedback on areas of concern that need to be addressed and provide a valuable starting point for further audit.

Recent large-scale studies, such as the Swedish obese subjects study, have clearly demonstrated the positive clinical outcomes resulting from bariatric surgery, such as reductions in myocardial infarction rates and mortality (1). Despite the significance of these results, it is important to bear in mind the many potential health hazards and costs that may ensue following bariatric surgery. The 2006 NICE guidelines (13) were developed taking into account these risks and recognize the need for careful patient selection, expert surgical and multidisciplinary intervention and intense preoperative and post-operative support. In the current economic climate, a number of trusts may be tempted to run obesity services without the level of multidisciplinary team support required to achieve optimal outcomes. These audit findings indicate some of the nutritional and food behavioural problems that may occur in the absence of an integrated specialist service.

The weight loss (averaging around a third of initial weight) and regain data obtained from this audit are comparable to those observed internationally, highlighting a trend towards increased weight regain over time, with a potential return of comorbidities (6). It has also been demonstrated that those who are followed-up less frequently tend to regain more weight than those frequently monitored by a specialist multidisciplinary team (3,4,14). The audit data also indicate variability in prescribing and/or poor compliance with micronutrient supplementation, with a significant proportion of respondents being identified with clinical deficiencies, despite a lack of systematic monitoring and review. It may be expected that the identified deficiencies represent only the tip of the iceberg in relation to optimal nutritional status.

The audit data indicate early post-operative intolerance of meat, leading to more prolonged problems in around a third of respondents, with implications for long-term iron status. Intolerances of some carbohydrate foods also caused lasting restrictive effects on the diets of a significant proportion of respondents, and could impact on overall diet quality. Early post-operative nutritional support is vital in overcoming the complications of dumping, diarrhoea and nausea (commonly caused by very sweet or fatty foods, overlarge portions or erratic eating patterns). A number of observers demonstrate that long-term specialist nutrition follow-up is also important in ensuring nutritional adequacy on a restricted diet (10,12,14).

The dissatisfaction with dietetic input among these respondents and desire for more, better informed information highlights the need for specialist dietetic input. It also partly reflects the limitations that some respondents recognized with the procedure as a means of solving their food and eating problems. Some observers have suggested that, although not an infallible guide, a number of variables may predict better outcomes, e.g. high esteem, good mental health, high socioeconomic status and realistic expectations (15) and that behavioural predictors can give some indication of how well patients will maintain weight loss (16).

Three distinct subgroups could be identified from these retrospective data. The first comprised individuals who used the surgery as an impetus to change their lifestyle, improve their diet and increase their exercise levels. These respondents were generally very satisfied with the procedure and with their weight loss and lifestyle. The second group apparently expected to lose weight without any change in diet or lifestyle and their diet histories generally indicated poor protein and micronutrient intakes. This group can be expected to experience more significant weight regain and dietary/nutritional problems in the long term. The third group comprised those individuals for whom the surgery has caused significant problems with food tolerance, has intensified pre-existing emotional problems and/or it has resulted in excessive weight loss or regain. Specialist preoperative assessment may have identified the characteristics and requirements of each group and so that support could have been provided accordingly.

Conclusion

  1. Top of page
  2. Summary
  3. Introduction
  4. Methods
  5. Findings
  6. Discussion
  7. Conclusion
  8. Conflict of Interest Statement
  9. Acknowledgements
  10. References

Bariatric surgery has a valuable place in the treatment of obese patients, and can be safe and effective provided it is undertaken in carefully selected patients and with appropriate ongoing monitoring. These audit findings provide the first tangible evidence regarding the nutritional and dietary outcomes of bariatric patients in Guernsey and suggest that there are some areas for concern. Although the weight losses are impressive in comparison with non-surgical techniques, the long-term data suggest a pattern of emerging dietary and nutritional problems and of significant weight regain. As a result of these findings a series of recommendations have been made, aiming to improve the local monitoring of post-surgical patients and those considering future surgery. These include regular re-audit, optimal use of the single dietetic session currently allocated to this group of patients, advice to general practitioners on preoperative support and referral, frequency of blood testing and on checking compliance with nutritional supplements, as well as a bid to increase the dietetic service provision to these patients.

Acknowledgements

  1. Top of page
  2. Summary
  3. Introduction
  4. Methods
  5. Findings
  6. Discussion
  7. Conclusion
  8. Conflict of Interest Statement
  9. Acknowledgements
  10. References

Thanks to Mr Michael Van den Bossche, Specialist in Gastrointestinal Surgery for his support, to Rachel Warry for administrative assistance and to all those who participated in the audit.

References

  1. Top of page
  2. Summary
  3. Introduction
  4. Methods
  5. Findings
  6. Discussion
  7. Conclusion
  8. Conflict of Interest Statement
  9. Acknowledgements
  10. References
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