Long-term risks and benefits of bariatric surgery: a research challenge.

Abstract

Bariatric surgery results in lastingweight loss and is recognized as improving metabolic aspects of obesity, for which long-term outcomes remain poorly defined. Many important research questions remain unanswered, contributing to limited use of bariatric surgery for both weight loss andmetabolic conditions. A workshop was recently convened by the National Institute of Diabetes and Digestive and Kidney Diseases and the Division of CardiovascularSciencesattheNationalHeart,Lung,andBloodInstitute toaddressthecurrentstatusandneedsofresearchaboutlong-termbariatric surgical outcomes.Detailed findings fromthisworkshopare reportedbyCourcoulasetal1 inJAMASurgery.Thebestavailableevidence regardingbariatric surgicaloutcomescomesfromlargeobservational studiesandfromrecentlyperformedrandomizedclinical trials (RCTs).1 Comparedwith the RCTs, the observational studies were larger with longer follow-up.Although thebest availableevidence is that “bariatric surgical procedures result in greater weight loss than nonsurgical treatment,”2 there isstill aneedformore informationabout long-term outcomes (at least 10years’worth) after surgical procedures. Ideally,RCTswouldbestcharacterize long-termoutcomesforbariatric surgery.However, thecostsof this typeof studyareprohibitive. AnRCTrequiresscreeningnumerouscandidatestoenrolloneandmust pay for clinical care. For anRCT tobegeneralizable, there should be a multicenterconsortium.Giventheheterogeneityofpatientsacrosscentersandtherelativehomogeneityofsurgicalprocedureswithincenters, the trialwouldneedvery largenumbersofpatients andcenters tobe adequatelypoweredandgeneralizable.Patientretentioninweight loss trials is particularlyproblematic, resulting inhighcosts attributable to maintainingpatients inthestudy.Thus,theworkshopparticipantsconcludedthatthemostpracticalapproachforobtaininginformationabout long-termrisksandbenefitsofbariatric surgerywouldbe tocombine informationfromseveralRCTsortoimplementwell-designedandwellexecutedobservationalstudies.However,combiningresults fromdissimilar RCTsmaynotbe feasible nor scientifically acceptable. For somequestions, suchas those aboutweight loss sustainability,comorbidityresponses,andmid-and long-termcomplications,existingresourcesmayanswer importantquestions.TheSwedishObese JAMASURGERY