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
Canadian Adult Obesity Clinical Practice Guidelines 7
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:[email protected]
References
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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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