Clinical Characteristics Of Users Of Weight Loss Drugs: Population-Based Case-Control Study

ObjectivesTo investigate clinical characteristics of users of weight loss drugs in Norway. DesignNested population-based case control study SettingNationwide healthcare registers in Norway with information on all dispensed medications linked to contacts with primary and specialist healthcare services. ParticipantsAll individuals aged 18-74 years with first dispensing of a weight loss drug (WLD) in 2023-2024, classified as initiators of 1) semaglutide (only Wegovy), 2) liraglutide (only Saxenda), 3) tirzepatide, 4) bupropion-naltrexone, or 5) orlistat. We matched each WLD user by sex and age to five controls randomly selected from the general Norwegian population. Main outcome measuresType and count of number of comorbidities diagnosed in the two years preceding initiation of WLD use, comedications dispensed in the preceding year, and any previous bariatric surgery. Differences between WLD users and population controls were estimated using conditional logistic regression adjusted for country of birth and education level. ResultsDuring 2023-24, 150,036 individuals initiated semaglutide, 4,603 liraglutide, 3,596 tirzepatide, 31,172 bupropion-naltrexone, and 1,411 orlistat. Among WLD users, 22-29% were registered without any of the pre-defined comorbidities, compared to around half of population controls. Comorbidities and comedications were generally observed at similar proportions in the different WLD user groups, but at much lower proportion for controls: hypertension: 32-38% of WLD users vs. 17-20% of controls; hyperlipidaemias: 20-24% vs. 12-15%; sleep apnoea: 7-11% vs. 2-3%; back pain: 15-20% vs. 10-11%; opioids: 24-30%vs. 13-15%; antidepressants: 20-24%vs. 10-11%. ConclusionsLike other countries, Norway faces the challenge of costly pharmacological obesity treatment, and the need for measures to mitigate increasing socioeconomic health disparities to ensure access to obesity treatment for those most likely to benefit including persons with multimorbidity. What is already known on this topicO_LIObesity is increasing worldwide and is associated with increased risk of multimorbidity. C_LIO_LIThe available treatment options for obesity have been rapidly and substantially transformed by the availability of new weight loss drugs. C_LI What this study addsO_LIThis nested case-control study within the Norwegian population examined clinical characteristics of new users of five weight loss drugs: semaglutide, liraglutide, tirzepatide, bupropion-naltrexone, and orlistat. The study identified a higher proportion of weight loss drugs users with cardiovascular, endocrine, mental, and other health conditions, as well as increased usage of cardiovascular, nervous system, and chronic pain medications, compared to the general population. C_LIO_LIThe majority of WLD users had high levels of multimorbidity and medication use compared to controls. Approximately 1 in 5 WLD users had no registered comorbidity in either primary or specialist health care systems. C_LIO_LIAdditionally, we noted differences in sociodemographic factors between users and population controls, such as lower education levels among WLD users. C_LIO_LIThe rapidly expanding use of weight loss drugs necessitates close attention from public health authorities. C_LI