Canadian Adult Obesity Clinical Practice Guidelines 1

KEY MESSAGES FOR HEALTHCARE PROVIDERS

• Adherencetoconsistentpost-operativebehaviouralchanges(behaviourmodification fornutritionplans,physical activityandvitamin intake)canoptimizeobesitymanagementandhealthwhileminimizingpost-operativecomplications.

• Working in partnership, the bariatric surgical centre, thelocalbariatricmedicinespecialist,theprimarycareproviderandthepatient livingwithobesityneedtoestablishandcommittoasharedcaremodelofchronicdiseasemanage-mentforlong-termfollow-up.

• The primary care provider should refer patients withpost-bariatric surgery complications back to the bariatricsurgicalcentre,ortoalocalbariatricmedicinespecialist.

Bariatric Surgery: Postoperative Management JudyShiaui,LaurentBierthoii

i) DivisionofEndocrinologyandMetabolism,UniversityofOttawa

ii) DepartmentofSurgery,LavalUniversity

Cite this Chapter

ShiauJ,BierthoL.CanadianAdultObesityClinicalPracticeGuidelines:BariatricSurgery:PostoperativeManagement.Downloadedfrom: https://obesitycanada.ca/guidelines/postop. Accessed[date].

Update History

Version1,August4,2020.AdultObesityClinicalPracticeGuidelinesarealivingdocument,withonlythelatestchapterspostedatobesitycanada.ca/guidelines.

RECOMMENDATIONS

1. Healthcareproviderscanencouragepeoplewhohaveun-dergonebariatricsurgerytoparticipateandmaximizetheiraccesstobehaviouralinterventionsandalliedhealthservicesatabariatricsurgicalcentre(Level2a,GradeB).1,2

2. We suggest thatbariatric surgical centres communicateacomprehensivecareplan toprimarycareprovidersonpa-tients who are discharged, including: bariatric procedure,emergency contactnumbers, annualblood tests required,long-term vitamin andmineral supplements,medications,behaviouralinterventionsandwhentoreferback(Level4,GradeD,consensus).

3. Wesuggestthatafterapatienthasbeendischargedfromthebariatric surgicalcentre,primarycareproviders shouldannuallyreview:nutritionalintake,activity,compliancewith

multivitaminandmineralsupplements,andweight,aswellasassesscomorbidities,orderlaboratoryteststoassessfornutritionaldeficienciesandinvestigateabnormalresultsandtreatasrequired(Level4,GradeD,consensus).

4. We suggest that primary care providers consider referralbacktothebariatricsurgicalcentreor toa localspecialistfortechnicalorgastrointestinalsymptoms,nutritionalissues,pregnancy, psychological support, weight regain or othermedicalissuesasdescribedinthischapterrelatedtobariatricsurgery(Level4,GradeD,consensus).

5. Wesuggestthatbariatricsurgicalcentresprovidefollow-upandappropriatelaboratorytestsatregularintervalspost-sur-gery with access to appropriate healthcare professionals(dietitian,nurse,socialworker,surgeon,bariatricphysician,psychologist/psychiatrist) until discharge is deemedappro-priateforthepatient(Level4,GradeD,consensus).

Canadian Adult Obesity Clinical Practice Guidelines 2

Post-bariatric surgery health behaviour changes

Post-bariatric surgery diet

Centres that perform bariatric surgerywill typically provide pa-tients with a dietary protocol to follow. Initially, over severalweeks,patientstransitionfromliquid,tosoftandthentoasol-id diet.Over the long term, patients are encouraged to followa structuredpost-bariatric surgicaldiet involving smallportions,three tofivebalancedandstructuredmealsandhealthysnacks(chew foods slowly and avoid sweets). For beverages, patientsshouldnoteatanddrinkatthesametime(avoidliquidswithin30minutesofeatingsolids).Carbonatedbeveragesandcaffeinateddrinks are to be avoided, as the phosphoric acid and caffeine,respectively,canincreasetheriskofulcerations.

After bariatric surgery, patients need to followa low-fat,mod-erate carbohydrate and high-protein diet. Post-operative pro-teinrecommendationsrangefrom1.2to1.5g/kg/daybasedongoalbodyweight(minimumof60gprotein/dayforlaparoscopicsleevegastrectomy/Roux-en-Ygastricbypass,and80–120g/dayforduodenal switch).Consultinga registereddietitian can sup-portchangesineatingbehavioursandguidepatientsontheirnu-tritionneeds.3Thereisnoadvantagetoprescribingalternatediets(e.g.lowcarbohydrate,highprotein),probioticsoraminoacids.4-6

Other behavioural changes to consider

Alcohol intakeshouldbeminimaloravoidedduetochanges inpharmacokinetics. For example, inwomenwho are post Roux-en-Ygastricbypass,twoalcoholicbeveragesareequivalentinab-sorptiontofouralcoholicbeverages.7Sevenpercentofpatientsreportnewhigh-riskalcoholuseoneyearafterbariatricsurgery,though,onamorepositivenote,halfwhoreportedhigh-riskalco-holusebeforesurgerydiscontinuedhigh-riskdrinking.7

Activity: Long term, a standard of 150 to 300minutes of ac-tivity/week is recommended for post-bariatric surgical patients.Post-operativehigher-volumeexercise canhelppromote furtherweightloss8-10butsustainingthislevelactivityisdifficult.11

Smoking cessation:Abstentionfromcigarettes isrecommend-ed.Cigarette smoking can increase riskofpepticulcerdisease,particularlymarginalulcers.

Marijuana:Thereisapaucityofstudiesontheuseofmarijuanapostbariatricsurgery.Oneconcernwouldbetheimpactofweightlossandthechronicuseofmarijuana,whichistraditionallyknownforits“munchies”effect.At thispoint,moderation, ifnotabsten-tion,wouldbeasaferecommendation.

Post-bariatric surgery vitamin supplementation

Theevidence for the roleof vitamin supplementation (amount,duration)variesdependingonwhichvitamin,mineralortypeofbariatricprocedurearestudied.Generally, sometypeofvitaminsupplementation is needed for all bariatric surgical procedures,with tailoring for those thathaveahypoabsorptive component(Roux-en-Ygastricbypass,duodenalswitch).

Practically,itmakessensethatastandardizedminimumprescrip-tion of vitamins be set for all bariatric surgeries. It is a naturalhumantendencytoeventuallyforgettakingsupplements.Settingastandardmeansthatclinicianscanbeconsistent intheirmes-sagingabouttakingvitamins.Deficienciesofvitaminsandsomemineralscan leaveseriousandpotentiallynonreversiblesideef-fects.Frequencyoflaboratorymonitoringmayvarydependingontheindividualandtypeofprocedure,butatminimumanannualcheck shouldbeconducted toensure thatpatientsarenotbe-comingmalnourished.Tables1and2summarizetherecommen-

KEY MESSAGES FOR PATIENTS LIVING WITH OBESITY WHO HAVE HAD BARIATRIC SURGERY

1.Ifyouhavehadbariatricsurgery,itisimportantforyoutotakeyournutritionalsupplementslifelongandtocontinuetofollowthepost-bariatricsurgicalnutritionplan,exerciseand any other recommendations given by your originalspecialistteam.Bydoingthis,youwillincreaseyourchancesofstayinghealthyandreducecomplicationsthatcanarisefrombariatricsurgery.

2.Attend all scheduled appointments and programmingoffered by your bariatric surgical site. Once you are dis-charged from the bariatric surgical site, schedule annualappointments with your primary care provider to checkyour bloodwork, reassess your medications and addressanyissuesrelatedtochangesinyourweight.

3. After bariatric surgery, it is possible that there can be anegativeimpactonmood,relationships,bodyimage,de-velopmentofaddictionsandreducedabilitytocopewithstress.Ifyouarestruggling,discussthiswithyouroriginalspecialistteamor,ifyouhavebeendischarged,withyourprimarycareprovider.

4.Rememberthatyourlowestweightpost-surgerywilloccurbetween 12 to 18months. After this, there is a naturalincreaseinweightthatoccurs.Ifyouaregainingexcessiveamountsofweight,discussthiswithyourbariatricteamorprimarycareprovider.

5.Ifyouare12to18monthspost-bariatricsurgeryandareplanningapregnancy,discussthiswithyourbariatricteam,primarycareproviderandobstetrician.

Canadian Adult Obesity Clinical Practice Guidelines 3

dationsforvitaminsupplementation,associateddeficitsthatcanoccurwithvariousdeficiencies,andfrequencyofmonitoring.Ta-ble3summarizesclinicalfeaturesthatmaypointtowardanutri-entdeficiency.Adietitiancanhelpdeterminewhatcombinationofvitaminsmakessenseforapatient.InCanada,accesstoall-in-onebariatricsupplementsforsurgicalpatients is improvingandcanhelpcomplianceby reducing thenumberofpills thatneedtobetaken.Gummyvitaminsshouldbeavoidedastheydonotcontainessentialminerals.

Post-bariatric surgery complications

Manygastrointestinal(dumpingsyndrome)andmetaboliccompli-cations(e.g.bone,kidneystones)canbepreventedbyfollowingtherecommendedpost-bariatricsurgerynutritionplanandvita-minintake.

Dumping syndrome

Dumping syndrome is divided into early and late phases. Earlydumpingsyndromeoccurswithinthefirsthourafterameal.Be-causeofthehyperosmolalityofthefood,rapidfluidshiftsoccurfromtheplasmacompartmentintotheintestinallumen,resultinginhypotensionandasympatheticnervoussystemresponse.Earlydumping is characterized by gastrointestinal symptoms such asabdominalpain,bloating,borborygmi,nauseaanddiarrhea,andvasomotor symptoms, such as fatigue, desire to lie down aftermeals (a classic symptom), flushing, palpitations, perspiration,tachycardia, hypotension, and, rarely, syncope. In contrast, latedumpingusuallyoccursonetothreehoursafteramealandisaresult of an incretin-driven hyperinsulinemic response after car-bohydrateingestion.Hypoglycemia-relatedsymptomsarerelatedto neuroglycopenia (fatigue, weakness, confusion, hunger andsyncope)andautonomic/adrenergicreactivity(perspiration,palpi-tations,tremorandirritability).12

Symptomsthatpersistdespitereturningtoapost-bariatricsurgerydietmaybenefitfromatrialofeitheracarbose,acalciumchannelblocker,diazoxideoroctreotide.Referral toabariatricmedicinespecialistoranendocrinologistformanagementandtoruleoutothercausesofhypoglycemia(nesidioblastosis,insulinoma,facti-tious)maybewarranted.13

Abdominal discomfort

Abdominaldiscomforthasa longdifferentialfromdietary indis-cretion(overeating),dumpingsyndrome,biliarycolic,stenosisofthegastro-jejunostomy,marginalulcerorsmallbowelobstruction.Presentationforsmallbowelobstructioncancomeatanytime,butcanbedividedintoearly(<30days;secondarytoadhesionsor incarceratedhernias)or late (>1 year; internalhernia,whichcanbeseenpostRoux-en-Ygastricbypassorduodenalswitch).Duringthefirstyear,thereisaneedforahigherlevelofsuspicionforpainsecondarytoasurgicalcomplication.Tachycardia,unsta-blevitalsignsandabdominalpainmaybesuggestiveofasurgicalleak, internal herniaor cholecystitis,whichwarrants immediate

surgicalreferral.Withdiarrhea,constipationorbloating,referraltoadietitiancanhelpidentifyhealthierfoodchoicesandproperfibrecontent.Probioticsmayimprovesymptomaticgastrointestinalepisodes.

There should be a high level of suspicion for an ulceration forpatientswhousenon-steroidalanti-inflammatorydrugs(NSAIDS).Referraltothebariatricsurgicalsiteshouldbeconsideredwhenclinical red flags appear such as unexplained, frequent,moder-ate-to-severe abdominal pain, daily intolerance to most solidfoods,dailynauseaandvomiting,and/orasignificantamountofweightregain(>25%–50%oftotalweightloss)inashortspaceof time. Every bariatric patient suffering from persistent vomit-ing severeenough to interferewith regularnutrition shouldbepromptlystartedonoralorparenteralthiaminesupplementation,evenintheabsenceorbeforeconfirmatorylaboratorydata.14

Bone health

Post-bariatricsurgery,bonedemineralization15–17andfracturerisk,18particularlyafterduodenal switch,are increased.Amajorcauseofbonelossisimpairedintestinalcalciumabsorption,whichleads to stimulation of parathyroid hormone (secondary hyper-parathyroidism)andboneresorption.17Theevidenceformonitor-ing,preventionandtreatmentisnotwelldescribed.Atminimum,adequateproteinintakeincombinationwithroutinephysicalac-tivityinadditiontotheroutinesupplementationofcalciumcitrateandvitaminDarerecommended.17,19ItisrecommendedtoadjustcalciumandvitaminD intaketoachievenormalserumcalcium,vitaminDandparathyroidhormonelevels.Calciumcitrateispre-ferredovercalciumcarbonateasitisbetterabsorbedintheab-senceofgastricacid.ElevatedparathyroidhormoneinthesettingofinappropriatelyhighserumcalciumandnormalvitaminDlevelsissuggestiveofprimaryhyperparathyroidismandrequiresfurtherinvestigation.

Theroleofbonemineraldensitytestingpriortobariatricsurgeryiscontroversial,20particularlyduetotechnicaldifficultieswhenpa-tientsareatahigherbodymassindex(BMI).Wesuggestorderingbonemineraldensitytestingonapatientattwoyearspost-surgery,whenweightisatitsnadir.Subsequentbonemineraldensitytest-ingcanbeorderedbasedonclinicalneed.20Ifapatientdoeshaveosteoporosis, then intravenous bisphosphonates (zolendronate 5mgonce a year, ibandronate 3mg every threemonths) are thepreferredchoice,asthere isariskofanastomoticulcerwithoralbisphosphonates.Priortostartingbisphosphonatetherapy,itisim-portantthatvitaminDlevelsbefullyrepletetopreventthedevel-opmentofhypocalcemia,hypophosphatemiaandosteomalacia.21

Nephrolithiasis

Patientswhohavehadbariatricsurgeryareathigherriskofnewonsetnephrolithiasis,withthemeanintervalfromsurgerytodi-agnosisofnephrolithiasisrangingfrom1.5to3.6years.Theriskofnephrolithiasis,typicallycalciumoxalatestones,variesbypro-cedure, being the highest for hypoabsorptive procedures (22%to28.7%),intermediateforRoux-en-Ygastricbypass(7.65%to

Canadian Adult Obesity Clinical Practice Guidelines 4

13%)andthelowestforpurelyrestrictiveprocedures(laparoscop-ic adjustable gastric banding, laparoscopic sleeve gastrectomy)whereitapproachesthatofnon-operativecontrols.22Unabsorbedfatintheintestinebindswithcalcium,whichtypicallywouldbindoxalate.Oxalate is reabsorbed from the intestine and is subse-quently filtered by the kidney, resulting in hyperoxaluria. Withconcomitanthypocitraturia(fromintestinalalkali loss),thereisahigherpropensityforcalciumoxalatestoneformation.Basicther-apeuticstrategiestomanagehyperoxaluriaincludecalciumcitratesupplementation, increased hydration, limiting dietary oxalateandadheringtoa low-fatdiet.17,23Commonly, individualsoftenbelievethatkidneystonesarecausedbytakingtoomuchcalcium,and that calcium supplementation shouldbediscontinued. Theexactoppositeistrue,inthattheyshouldremainontheircalciumcitratesupplementation,whichnotonlyhelpsbindintestinaloxa-latebutalsoprovidescitratefortheurine.Thereissomeevidencetosuggest thatpyridoxine (B6)deficiencyplaysa role inkidneystone formation, highlighting the importance of taking vitaminsupplementation consistently.24 Certain probiotics (containingeitherLactobacillus aloneor in combinationwithStreptococcus thermophilus and Bifidobacterium)mayplayacomplimentaryroleinreducinggastrointestinaloxalateabsorptionifbasicstrategiesareinsufficient.25,26

Psychological complications and treatments post op

Thoughbariatric surgery isoneof themosteffective treatmentoptions for obesity, clinicians should be aware of the potentialpost-bariatric psychological issues thatmay arise, including de-pression, suicide,27,28 body image disorder, eating disorders,29

andsubstanceandalcoholabuse.7Resultsfrombariatricsurgerymaynotmeet apatient’s expectationsormaynot lead towardhoped improvements in quality of life, thus impactingmood.14 Beyond providing knowledge on diet and exercise, cliniciansshouldaddressimprovementinpatient’sself-esteemandself-mo-tivation.Patientswhohavehadpost-bariatriccomprehensivebe-havioural-motivationalnutritioneducationhavedecreasedriskfordepressionandimprovedweightlossoutcomes.1,30,31Primarycareprovidersmayneedtoreferthepost-bariatricsurgicalpatientformorein-depthpsychologicalcounselling,suchascognitiveordi-alecticalbehaviourtherapy.RefertoTheRoleofMentalHealthinObesityMedicine and EffectivePsychologicalandBehaviouralIn-terventionsforPeopleLivingwithObesitychaptersformoredetails.

Weight regain

Nadir weight (lowest weight point) occurs one to two yearspost-bariatricsurgery.Weightlossstopspartlybecauseofadaptivechanges inthe intestine,changedpatienthabits,andmetabolicadaptation.32Afterthis,itisnormaltoexpectsomeweightregain.However,thereisnoconsistentabsolutenumberintheliteraturethat defines pathological weight regain post bariatric surgery.Studiesthathavebeenconductedinthebariatricsurgerypopu-lationshowthatsignificantweightregain(≥15%gainofinitialweightlosspostbariatricsurgery)occursin25%–35%ofpeoplewhoundergosurgerytwotofiveyearsaftertheirinitialsurgicaldate.33 The SwedishObese Subjects study, the largest non-ran-

domizedinterventiontrialcomparingweight lossoutcomesinagroupofover4000surgicalandnonsurgicalindividuals,reportedthat,at10years, individualswhounderwentRoux-en-Ygastricbypasshadameanweightregainof12%oftotalbodyweight,whichtranslatesintoregaining34%ofthemaximallostweightachievedatoneyear.29,34TheconsensusforsomeCanadianbar-iatricsurgicalsitesisthatweightregainisdefinedas>25%regainoftotalweightlost.Theunderlyingfactorsthatinfluenceweightregain followingbariatric surgeryaremultifactorial,and includeendocrine/metabolicalterations,anatomic surgical failure,nutri-tionalindiscretion,mentalhealthissuesandphysicalinactivity.29

Evenpriortosurgery,emphasizingrealisticweighttrajectoriesandexpectationsmaytheoreticallyhelpreducetheanxietythatsomepatientsgothroughastheymentallytrytotransitionfromlosingweighttohealthylivingandmaintainingweightloss.Patientswhoexperienceweightregainmayperceivethatthesurgeryhasfailed,ortheymayenteracycleofhelplessnessbyblamingthemselvesandfeelingshamed.Itisimportantthatcliniciansmitigatethesefeelingsbyexplainingthatsomeweightregainfollowingbariatricsurgeryisnormal,andthenproceedinginastepwiseapproachtoaddresstheweightregain.Itisneithernecessarynoreconomicaltoorderanesophagogastroduodenoscopyoranuppergastroin-testinalcontraststudytoevaluatethegastrointestinaltractonev-erypatientwhoisexperiencingweightregainfollowingsurgery.Thefollowingstepsaresuggestedtoaddressweightregain:

• Ensurethatthepatientcontinuestofollowtherecommendedpost-bariatricsurgerynutritionplanandvitaminintake.Checkbloodworktoensurethatvitaminandminerallevelsareinthenormal range. If a person is malnourished at baseline, thenmoreharmoccurstryingtohelpthepersonlosefurtherweight.Referraltoadietitiancanbehelpfulatthisstage.

• Psychological interventionmaybe required toaddressmood,anxiety,aneatingdisorder,ortohelpapatientmakebehaviourchanges.

• Ifonsubsequentfollowups,despiteadherencetopost-bariat-ricsurgerynutritionplanandvitaminintake,weightdoesnotdecrease,thenanesophagogastroduodenoscopyoruppergas-trointestinalcontraststudymayruleoutananatomicalfailure.Detectionofananatomicalfailurewouldleadtoareferralbackthebariatricsurgicalteam.

• Consideration of medications for obesity managementpost-bariatricsurgerymaybemadeforpatientswhoaretryingto follow the post-bariatrc surgery nutrition plan and takingtheirvitaminsupplementation.Orlistatshouldnotbeused inpatientswhohavehadhypoabsorptiveprocedures.Retrospec-tivereportshavedemonstratedthatliraglutide35,36orbupropi-on/naltrexone37mayplayaroleinreducingweightregain.

Afteralltheabovesteps, ifweightregainstill remainsanissue,thenconsiderreferringbacktoabariatricsurgerycentreforeligi-bilityofsurgicalrevision.

Canadian Adult Obesity Clinical Practice Guidelines 5

Medications

Followingbariatric surgery and the resultingweight loss,manystudiesdemonstrateareductionofmedicationsfordiabetes,dys-lipidemia,cardiovascularandantihypertensiveagents.Therearealimitednumberofpublicationsthatfocusonthepharmacody-namicsofmedicationspost-operatively(Table4).Ultimately,thereremainsa large interindividual variationand the therapeuticef-fectsofamedicationmustbeindividuallydoseadjusted.

Forthefirstthreetoeightweekspost-surgery,medicationsshouldbeconsumedinacrushedorliquidformorbyopeningcapsulecontents.Itisimportantthattheliquidformdoesnotcontainab-sorbablesugarstoavoiddumpingsyndrome.38Somemedications,however,shouldnotbecrushed.39PostRoux-en-Ygastricbypassandduodenalswitch,thepharmacokineticprofileofmanymed-icinesmaybealtereddue tochanged intestinalabsorption sur-face,lipophilicityofdrugs,increasedpHinthestomach,reducedcytochromeP450 (CYP) enzymeactivity andfirst-pass intestinalmetabolism,timeafterbariatricsurgery,andchanges involumeof distribution.40 Immediate-release formulations are generallypreferredoverextendedrelease.Nonsteroidalanti-inflammatorydrugsshouldbeavoidedafterRoux-en-Ygastricbypassorduo-denal switchdue to riskofanastomoticulceration/perforations.For other bariatric procedures, non-steroidal anti-inflammitories(NSAIDs)useshouldbeaccompaniedwithprotonpumpinhibitors(PPIs)formucosalprotection.41PatientswhoneedtoremainonlowdoseaspirinforsecondarypreventionmaydosobutshouldhaveadditionalPPIprotection.EspeciallyforRoux-en-Ygastricby-passandduodenalswitchprocedures,patientstakinglong-termwarfarin require a postoperative dose reduction of >20%withcloselymonitoredinternationalnormalizedratio(INR).Directoralanticoagulants (DOACs)shouldbeavoidedduetothepotentialfor decreased drug absorption. If a betablocker after bariatricsurgeryisneeded,ahydrophiliccompoundlikeatenololmaybepreferred. Bioavailability of oral contraceptivesmay be reducedpost-bariatric surgery, and alternate methods of contraceptionneed tobeconsidered.Antidiabeticmedicationswitha risk forhypoglycemia(suchassulfonylureas)shouldbediscontinuedandinsulindosesadjusted.Metforminmaybecontinuedbutthedosemayneedtobereduceddueto increasedabsorption.42Primarycareprovidersmaybenefitfromworkingwithapatient’scommu-nitypharmacistformedicationadjustments.

Special considerations for bariatric surgery on fertility

Bariatricsurgeryshouldnotbeconsideredatreatmentforainfer-tility.54Many studies related to fertility inwomen post-bariatricsurgery are small, and appropriate control groups have not al-waysbeenincluded.Together,theevidencesuggeststhatbariatricsurgeryimprovesfertility,whetheritisthroughimprovementsofsexhormonalprofilesorresolutionofpolycysticovarysyndromemarkerswhichinfluencefertility(includinganovulation,hirsutism,hormonalchanges,insulinresistance,sexualactivityandlibido).55 The type of surgery does not appear to be related to changes

infertility,asonlytheamountofweightlost(aBMIdecreaseofgreaterthan5kg/m2)andtheBMIachievedattimeofconceptionwerepredictiveofbecomingpregnant.56

Inmen,surgery-inducedmassiveweightlossdoesnotimpactspermquality,butitdoesincreasethequalityofsexualfunction,totaltes-tosterone,freetestosteroneandFSH,andreducesprolactin.57Over-all,inmen,thebalancebetweenpositive(hormonal,psychologicalandsexualimprovements)andnegative(nutritionaldepletionduetoselectivefoodmaldigestionandmalabsorption)impactswillde-terminethefinaleffectonseminalqualityandfertility.57

Womenwhobecamepregnantbeforeoneyearafterbariatricsur-gerypresentedwithahigherrateoffetallossincomparisontowom-enwhosepregnancyoccurredafterthisperiodoftime(35.5versus16.3%).Pregnancyisthereforenotrecommendedinthefirst12–18monthsfollowingbariatricsurgery,58bywhichtimeweightismorestableandwomenareabletoconsumeanutritionallybalanceddiet.Thus,adequatecontraceptionshouldbeofferedtowomenofrepro-ductiveagewhoundergobariatricsurgery.Asestrogenisabsorbedintheuppergastrointestinaltractwhich ismodifiedduringbariat-ricsurgery,oralcontraceptionpillsshouldbeavoidedforRoux-en-Ygastricbypassandbiliopancreaticdiversion/duodenalswitch.Instead,normalformsofhormonalcontraception(etonogestrelimplant59ora levonorgestrel releasing intrauterinedevice60maybeconsidered.Thereisnodefinitivecontraindicationtooralcontraceptionpillsforgastricbandingandsleevegastrectomy.14,61

Special considerations in women who have had bariatric surgery and pregnancy

Comparedwithwomenwhohaveobesityandwhohavenotun-dergone bariatric surgery, womenwho became pregnant afterbariatricsurgeryhadalowerriskofgestationaldiabetes,hyper-tensivedisorders,andmacrosomia.However,riskofsmall-for-ges-tational-agenewbornsincreasesafterbariatricsurgery.62

Preconception care

Womenplanning conceptionpost-bariatric surgery shouldhavedailyoralsupplementationwithamultivitamincontaining1.0mgfolic acid, beginning at least three months before conception.Women should continue this regime until 12weeks gestation-alage.From12weeksgestationalage,continuingthroughthepregnancy, and for four to sixweekspostpartumor as longasbreastfeedingcontinues,continueddailysupplementationshouldconsistofamultivitaminwith0.8mgto1.0mgfolicacid.63B12levelsshouldbecheckedandcorrectedifdeficientpriortoinitia-tionofadditionalfolicacid.WomenareadvisedtoavoidvitaminandmineralpreparationswhichcontainvitaminAintheretinolforminthefirst12weeksofpregnancy,assupplementscontain-ingretinolmayincreasetheteratogenicrisk(especiallyinthefirsttrimester).Itisthereforerecommendedthatpregnantwomenandthoseplanningpregnanciesfollowingbariatricsurgeryaresupple-mentedwithvitaminAinthebeta-caroteneform.

Canadian Adult Obesity Clinical Practice Guidelines 6

Nutritional monitoring during pregnancy

Standardcompletemultivitaminsroutinelyusedpost-bariatricsur-gery shouldbe substituted forprenatalmultivitamins to reducevitaminAintake,whichshouldnotexceed5000IU/day.Continueallotherregularsupplementationthatthepatienttypicallywouldbeon,andthenadjustaccordingtolaboratorytesting.Laboratorytesting at each trimester should includeCBC, ferritin, albumin,B12,25-Hydroxy (OH)vitaminD,calcium,parathyroidhormoneandfolate.Patientswhohavehadhypoabsorptivesurgeryshouldadditionallyhavezinc,copperandvitaminAlevels(andpossiblyvitaminEandK levelswithduodenal switch)monitoredduringpregnancy.14,55,64,65

IfthepatientisvitaminAdeficient,thensupplementationshouldbe in the form of beta-carotene vitaminA.64 Patients sufferingfromnauseaandintractablevomitingshouldhaveimmediateB1supplementation and carefulmonitoring of B1 levels. Nutritionadvicefromanexperiencedregistereddietitianshouldbeofferedtoreviewdeficiencies,vitaminsupplementationandensurearec-ommendeddailyproteinintakeof60g.54Possiblerecommendedgestationalweightgainwouldbebasedonpre-pregnancyBMIaspertheInstituteofMedicine.66

Other considerations during pregnancy

Inadditiontonutritionaldeficiencies, there isalsothepotentialforsevere,life-threateningcomplications,suchasinternalhernias,bowelobstructions, volvulus, intussusceptionandgastric perfo-

rations,whichgenerallyoccurone to threeyearsafterbariatricsurgery. Because of the upward pressure from the gravid uter-us,theselatesequelaemaypresentinpregnancyandduringtheimmediatepostpartumperiod.Abdominalpain inapost-bariat-ricsurgicalgravidwomanwouldneedtoincludethesepotentialcomplicationsinthedifferentialdiagnoses.Radiologicevaluationwithcomputedtomographyscanshouldbereviewedbybariatricsurgeonsorradiologistswithspecializedexpertiseinthisarea.67

Post-surgicalpatientsmaynottoleratethe50gglucosesolutioncommonlyadministeredat24–28weeksofgestation to screenforgestationaldiabetes.Alternativemeasurestoscreenforges-tationaldiabetesshouldbeconsideredforpatientswhohaveun-dergonehypoabsorptive-type surgery.Oneproposedalternativeishomeglucosemonitoring (fastingand two-hourpostprandialbloodsugar)forapproximatelyoneweekduringthe24–28weeksofgestation.54

Postpartum

Breastfeedingshouldbeencouraged.Itisimportantthatpostpar-tumbariatricsurgicalpatientscontinuetheirrecommendedvitaminsupplementation,astherehavebeendocumentedcasesofnutri-tionaldeficienciesinbreastfedinfantsborntomotherswhohavehadRoux-en-Ygastricbypass.68

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Table 1: Post-Bariatric Surgery Nutrition and Exercise, Vitamin Supplementation and Monitoring for Prevention of Complications

Vitamins and minerals

Daily prevention recommendation post- bariatric surgery (solid line means difference in dosing; — means no evidence of difference in dosing between the types of bariatric surgery)

Description of supplement with suggested timing (most patients will require complete multivitamins [MVs] with additional supple-mentation of B12, D, calcium and iron)

Post-bariatricsurgerynutritionandexercise:Eat3–5smallmeals;chewfoodslowly;aimforminimum60gprotein/day(LS/RYGB)or80g–120gprotein/day(duodenalswitch/DS);separateliquidsandsolidsby30minutes;nocarbonatedorcaffeinatedbeverages;minimaltonoalcoholintake;nosmoking,noNSAIDsorDOACSpostRYGBandDS;activity:150to300minutes/week.

VitaminB2(Riboflavin)

VitaminB3(Niacin)

Pantothenicacid(B5)

VitaminB6

Biotin

VitaminC

Selenium

Magnesium

Manganese

Chromium

Molybdenum

Zinc

Copper

VitaminA

VitaminK

VitaminE

Folicacid

Folicacid(pre-conceptionto12weeksGA)

Folicacidfrom>12wkstobreastfeeding/or4–6wkspostpartum

TakecompleteMVsatbreakfast.

ThevitaminsandmineralslistedontheleftcanbefoundinOTCcompleteMVs.Patientsandcliniciansneedtocarefullychecklabelsasformulationsdifferbetweenbrandsandsometimescanchange.

Generally,patientswillneedtwocompleteOTCMV/daytoreachthedailyrecommendationspostbariatricsurgery.

Theratioofzinc:coppershouldremain8–15mg:1mg.

Somemarketedvitaminsarelabelledaspostbariatricsurgeryvitaminsbutmaystillneedadditionalcalcium,iron,B12orvitaminDsupplementation.Readlabelscarefullyandadjustaccordingtolabresults.

Ifpregnant,switchOTCMVtoprenatalvitamin,nottoexceed5000IUofvitaminAperday.Avoidreti-nol-basedvitaminAduringpregnancyandlactation;itissafetocontinuebeta-carotene.AdditionalscreeningandincreasedrequirementsofvitaminAinduodenalswitchorifsteatorrheapresents.

LaparoscopicAdjustableGastricBandingorSleeve

8–11mg

1mg

5000–10000IU

90–120mcg

Roux-en-YGastricBypass

3.4mg

40mg

20mg

4mg

60mcg

120mg

140mcg

400mg

4mg

120mcg

50mcg

8–22mg

1–2mg

5000–10000IU

90–120mcg

15mg

400–800mcg

1000mcg

800–1000mcgDuodenalSwitch

DuodenalSwitch

16–22mg

2mg

10000IU

300mcg

Canadian Adult Obesity Clinical Practice Guidelines 8

ADDITIONAL SUPPLEMENTS

Vitamins and minerals

LAGB or LS RYGB DSDescription of supplement with suggested timing

VitaminB1(thiamine)

VitaminB1forat-riskpatients*

VitaminB12

VitaminD

Calcium(fromfoodandsupplements)

Iron

Lowrisk(menandpatientswithouthistoryofanemia)

Menstruatingwomen

*At-riskfactorsincludeGIsymptomssuchasintractablenauseaandvomiting,malnutrition,excessiveand/orrapidweightloss,excessivealcoholuse

12mg

50–100mg

350–500ug

3000IU

1200–1500mg1200–1500mg

18mg

45–60mg

1800–2400mg

IfinsufficientamountincompleteMV,adda50mgB-complexsupplementTakeatbreakfast

Taketwo50mgB-complexsupplements

TakeatbreakfastOral:350–500ug/dayNasalspray:asdirectedbymanufacturerParenteral(IMorSC):1000ugmonthly

TakeatbreakfastTitratevitaminDsupplementation:Tomaintain25(OH)Dlevelsat>75nmol/LToparathyroidhormonelevels

Itisnotuncommonthatforduodenalswitch,highersupplementationofvitaminD(ashighas50,000IU2-3times/week)mayberequired.

D3(cholecalciferol)ispreferredoverD2(ergocalciferol)foritsmorepotenteffect

TakeindivideddosesCalciumcitrate(preferred)withorwithoutmealsCalciumcarbonatewithmealsTitratetocalciumandparathyroidhormonelevels

TakebeforebedDonottakewithcalciumasabsorptionblocked.

Ferroussulphateisthepreferredironsupplement,butothersmaybeconsideredifthissupplementisnottolerated

TakewithvitaminC250–500mgforbetterabsorptionwithnon-hemeironsupplements

Formulationsofdifferentnon-hemeironsupplements(elementalironmg):•Ferroussulphate300mg(60mg)•Ferrousgluconate300mg(35mg)•Ferrousfumarate300mg(99mg)

Thereisnoevidencefortheroleofhemeironsupplements(11mgelementalhemeiron/tablet)forpreventionofanemiainpostbariatricsurgicalpatients.However,ifthisiswhatistoleratedclinically,carefulmonitoringofCBCandferritinlevelsarewarranted

Canadian Adult Obesity Clinical Practice Guidelines 9

LAB MONITORING

LAGB or LS RYGB DS Comments

Labvaluestomonitor

Labfrequency

Firstyearpost-op:

Thereafter:

CBC,electrolytes,albumin,ferritin,B12,folate,calcium,25(OH)vitaminD,PTH

Every3–6 months

Yearly

SameasLAGB/LS+vitaminA,zinc,copper

Every3-6months

Yearly

SameasRYGB+INR

Every3months

Every6-12months

Screenforthiamineforat-riskpatients*orwhohave clinicalfeaturesrelatedtothiaminedeficiency(seeTable2)

Inpregnancy,labsshouldbemonitoredeachtrimester:CBC,ferritin,albumin,B12,25(OH)D,calcium,PTH,folate

Forhypoabsorptivesurgeriesaddzinc,copper,vitaminA(forduodenalswitchpossiblyaddvitaminEandvitaminK)VitaminAlevelswithRYGBandDSneedtobeadjusted

*AtriskfactorsincludeGIsymptomssuchasintractablenauseaandvomiting,malnutrition,excessiveand/orrapidweightloss,excessivealcoholuseLAGB:laparoscopicadjustablegastricbanding;LS:laparoscopicsleeve;RYGB:Roux-en-Ygastricbypass;DS:duodenalswitch;NSAIDs:non-steroidalanti-inflammatorydrugs;DOACs:directoralanticoagulants;OTC:over-the-counter;MV:multivitamin;CBC:completebloodcount

Source:Shiau,J.

Table 2: Treatment for Post-Operative Deficiencies and Suggested Supplementation43–47

Micronutrient Post-op deficiency prevalence

Food SourcesSigns/symptoms of deficiency

Treatment for deficiency

VitaminB3(niacin)

Magnesium

Zinc

Copper

32%

LS:12%RYGB:21–33%DS:74–91%

RYGB:2%DS:10–24%

Yeast,liver,cereals,legumes,seeds

Meat,chicken,nuts,lentils,breakfastcerealsarefortified

Everything(vegetables,grains,meat,fish,poultry)

4D’sofPellegra:Dermatitis:photosensitive,pigmentedDiarrheaDementiaDeath

Musclecontractions,pain,spasms,osteoporosis

Skinlesions,poorwoundhealing,dermatitis,bluntingoftastesense,hairloss,alteredimmunefunction,alopecia, glossitis,infertility

Anemia,leukopenia,hypopigmentationofhair,skin,nails,unsteadygait,numbnessandtinglinginhandsandfeet,painfulparesthesia,poorwoundhealing,peripheralneuropathy,myelopathy,paralysis

Oralmagnesium

Remember:Zinc:copper:8–15mg:1mgaszincsupplementationcancauseadeficiencyincopper(e.g.:iftakingzinc50mg/d,thenaddcopper4mg/d)

Ifcopperdeficient:Mild-moderatedeficiency(includinglowhematologicindices):3–8mg/dcoppergluconateorsulfateSeveredeficiency:2–4mg/divcopperfor6daysoruntilserumlevelsreturntonormalandneurologicsymptomsresolve.

Toxicitylevel:Zinc24-hurine>1200ug/dCopperwomen>155ug/dLCoppermen>140ug/dL

Canadian Adult Obesity Clinical Practice Guidelines 10

Micronutrient Post-op deficiency prevalence

Food SourcesSigns/symptoms of deficiency

Treatment for deficiency

VitaminA

VitaminE

VitaminK

Folicacid

VitaminB12

VitaminB1(thiamine)

9–38%

2yearspostRYGB/DS:4to62%;

5yearspostRYGB/DS19–35%

Upto49%

RYGB:8–11%DS:61–69%

PreformedvitaminA(retinol):liver,kidney,eggyolk,butter

ProvitaminA (beta-carotene):leafygreens,carrots,sweetpotatoes

Oliveoil,meat,eggs,leafy vegetables

Animalproducts,leafyvegetables;easilydestroyedbyheatofcooking

Meatanddairyproducts

Yeast,legumes,pork,rice,cereals;denaturedathightemperature

Lossofnocturnalvision,Bitot’sspots(foamywhitespotsonsclera),itching,dryhair,xeropthalmia,decreasedimmunity,poorwoundhealing,hyperkera-tinizationoftheskin,lossoftaste(VitAandzincmetabolisminterrelated).

Nocornealchanges:10000–25000IU/dayorallyfor1–2weeks

Corneallesionspresent:50000–100000IU/dayimfor3days followedby50000IU/dayimfor2weeks

Toxicitylevel:>80ug/dL

Gaitataxia,hyporeflexia/weakness,nystagmus,ophthalmoplegia,ceroiddepositioninmuscle

Skinhemorrhages (petechia,purpura, ecchymosis)

Macrocyticanemia, palpitations,fatigue,neuraltubedefects,changesinpigmentationorulcerationofskin,nails,ororalmucosa

Perniciousanemia,tinglinginfingersandtoes,de-pression,dementia,ataxia,soretongue,smoothand“beefyred”tongue,paleskin,slightlyictericskinandeyes.

Dryberiberi:symmetricalperipheralneuropathy;convulsions,muscleweak-ness+/-painoflowerandupperextremities,brisktendonreflexes

Wetberiberi:heartfailure,tachycardiaorbradycardia,lacticacidosis,dyspnea,legedema,RVdilatation

Wernicke’sencephalopa-thy:polyneuropathyandataxia,ocularchanges(ophthalmoplegiaandnystagmus),confabulation,short-termmemoryloss

Korsakoffpsychosis: psychosisand/or hallucinations

Forpostbariatricsurgerypatientswithhypoabsorption,therecommendeddosageofvitaminKiseither1–2mg/dorallyor1–2mg/wkparenterally

1mg/dayorallyfor1–3months

1000or2000ug/day(1–2ampoules)orally

or

1000ug/weekim

Treatforsuspectedthiaminedefi-ciencybeforeorintheabsenceoflabconfirmation.

Oral:100mgbid-tiduntilsymptomsresolve

IV:200mgtidor500mgod-bidfor3–5days,followedby250mg/dfor3–5doruntilsymptomsresolve.im:250mgodfor3–5daysor100–250mgmonthly

Simultaneousadministrationofmag-nesium,potassiumandphosphorusshouldbegiventopatientsatriskforrefeedingsyndrome.

Canadian Adult Obesity Clinical Practice Guidelines 11

Micronutrient Post-op deficiency prevalence

Food SourcesSigns/symptoms of deficiency

Treatment for deficiency

VitaminD

Calcium(fromfoodandsupplements)

Iron

25–80%

Approx.10%

LS:17%

RYGB/DS:30%(45%after2years)

E.g.:food=mgcalcium1cupmilk=300mg1ozcheese=250mg¾cupyogurt=200mg½cupcookedleafygreens=50mg

Osteomalacia,arthralgia,depression,fasciculation,myalgia

Lowbonedensity, osteoporosis,musclecontractions,bonepain,spasms,paresthesia, muscleweakness,tetany

Fatigue,impairedworkperformanceandproduc-tivity,microcyticanemia,decreasedimmunefunc-tion,enteropathy,glossitis,dysphagia,spoon-shapednails(koilonychias),verticalridgeonnails

VitD3ismorepotentthanVitD2whencomparingfrequencyandamountneededforrepletion.

VitaminD33000to6000IU/d

or

VitaminD250,000IU1–3timesweekly.

Toxicitylevel:>150ng/mL

AdjustcalciumandvitaminDintakebasedonnormalizinglabvaluesofcalcium,25(OH)vitaminDandPTHlevels

Canincreaseoralnon-hemeiron intakeindivideddosestoprovide150–200mgelementalirondaily(e.g.:ferroussulfate300mgtid)48

Takeseparatelyfromcalciumsupple-ments,acid-reducingmedications–ifnoresponse,thenconsiderparenteralironadministration

HemeironfortreatmentofpostRoux-en-Ygastricbypassirondefi-ciencyisnotrecommendedasfirstlinebutmaybeconsideredifpatientdoesnottoleratenon-hemeiron;Thedosingwouldbe4tabletsofhemeirondaily.

Source:Shiau,J.

Canadian Adult Obesity Clinical Practice Guidelines 12

Source:Shiau,J.

Table 3: Clinical Features that Patients Might Present Post-Bariatric Surgery with Possible RelatedNutrient Deficiency43,47

Clinical features

HairAlopeciaCorkscrewhair

EyesNightblindness,ocularxerosis,keratomalacia,Bitot’sspotsOphthalmoplegiaOpticneuropathy

Face/skinDermatitis:hyperpigmentationaroundsun-exposedskin:face,neckandhandsimpairedwoundhealingPetechia,purpura

MouthSoreness,burningAngularstomatitisorcheilitisPicaHypogeusiaordysgeusiaGlossitis(sore,swollen,redandsmoothtongue)Gingivalbleeding

Beefyredtongue

NailsBeau’slines(transverseridges,horizontalgrooves)KoilonychiaSplinterhemorrhageBrittle,soft,dry,weak,thin;spliteasy

MusculoskeletalBonepainCalftenderness,absentdeeptendonreflexes,footandwristdropPeripheralneuropathy,tingling,“pinsandneedles”Muscletwitching,convulsions,tetanyMusclecrampsMusclepain

SexualHypogonadism,erectiledysfunction

HematologyAnemiaandfatigueMicrocyticanemiaMacrocyticanemiaNeutropenia

NervousSystemAtaxiaMyelopathyPolyradiculopathyNeuropathy

MyopathyDementiaAmnesia,hallucinations,confabulationConfusion,encephalopathy

HeartCardiomyopathyHeartfailure

Possible micronutrient deficiency

Iron,zinc,biotin,proteindeficiencyVitaminC

VitaminAThiamine,vitaminEB12,thiamine(Wernicke),copper(rarelyfolate)

NiacinZinc,VitC,proteindeficiency,VitC,VitK

Riboflavin(B2)B2,niacin,iron,B6,B12;orvitaminAtoxicityIron,zincZincFolate,riboflavin,niacin,B6,B2,folate,severeirondeficiencyVitaminC,niacin,folate,zinc,severevitaminDdeficiency;orvitaminAtoxicityFolate,niacin,B12

Zinc,protein,calciumIron,protein,anemiaVitaminCMagnesium;orvitaminAtoxicityandseleniumtoxicity

VitaminDThiamineFolate,B6,pantothenicacid,phosphate,thiamine,B12Calcium,vitaminD,Mgdeficiency,B6(orexcessMgandB6)Chloride,sodium,potassium,magnesium,calcium,vitamin,dehydrationVitaminD,biotin

Zinc

Protein,zinc,copper,seleniumIron,copper,pyridoxine,vitaminEB12,folateCopper

B12,copperB2,copper(rarelyfolate,vitaminE)ThiamineB12,thiamine(Wernicke),copper(rarelypyridoxine,folate,niacin, vitaminE)VitaminD,vitaminENiacin,B12Thiamine(Korsakoff)Thiamine(Wernicke),B12

SeleniumThiamine

Canadian Adult Obesity Clinical Practice Guidelines 13

Correspondence:guidelines@obesitynetwork.ca

References

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Downloadedfrom:https://obesitycanada.ca/guidelines/postop

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ThesummaryoftheCanadianAdultObesityClinicalPracticeGuidelineispublishedintheCanadianMedicalAssociationJournal,andcontainsinformationonthefullmethodology, managementofauthors’competinginterests,abriefoverviewofallrecommendationsandotherdetails.MoredetailedguidelinechaptersarepublishedontheObesityCanadawebsiteatwww.obesitycanada.ca/guidelines.

Table 4: Pharmacotherapy After Bariatric Surgery

Increased concentration

Atorvastatinshort-term8weeks49

Metformin42

Morphine50

Acetaminophen

Moxifloxacin51

List of medications not to be crushed

Alendronate,bisacodyl,bupropion,ciprofloxacin,diltiazem,dipyridamole/ASA,divalproex,felodipine,ferroussulfate,fexofenadine,finasteride,glipizide,lansoprazole,lithium,loratadine,metformin,metoprolol,morphine,nifedipine,omeprazole,pantoprazole,phenytoin,piroxicam,prednisolone,pseudoephedrine,rabeprazole,tamsulosin,verapamil39

Decreased concentration

Atorvastatinlong-term2years49

Levothyroxine38

Cyclosporin38

Phenytoin38

Rifampin38

Sertraline

SRI(SSRImorelikelytodecreasethanSNRI)reducedat1monthand

thennormalat1year52

Tamoxifen53

Source:Shiau,J.

Canadian Adult Obesity Clinical Practice Guidelines 14

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Canadian Adult Obesity Clinical Practice Guidelines 15

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