Determinants of adherence to obesity medication: A narrative review

Summary

The increasing prevalence of obesity, complex nature of this chronic disease, and risks of developing obesity‐related comorbidities outline the need for sustainable and effective management for people living with obesity. In addition to behavioral interventions, obesity medications (OMs) are increasingly considered an integral part of management of people living with obesity. OM adherence is essential to achieve the health benefits of these medications. Adherence to medications, defined as the process by which patients take their medications as prescribed, is determined by a range of factors and can be broken down into phases: initiation, implementation, and persistence (the persistence phase includes discontinuation/stopping treatment). Obesity‐specific challenges exist to optimize OM adherence, which may explain varying OM adherence compared with medication for other chronic diseases (diabetes, hypertension, dyslipidemia, and osteoporosis). However, lessons can be learned from other chronic diseases to improve OM adherence, for example from type 2 diabetes and hypertension. This review aims to provide practical guidance for identifying OM‐ and obesity‐specific determinants of adherence and discusses adherence determinants per adherence phase and obesity management phase (weight gain, weight loss, and weight stabilization/regain). This practical guidance will assist with developing obesity‐specific interventions to improve OM adherence.

Practitioner Points

• OMs are increasingly considered as an integral part of obesity management; however, like with all chronic disease medications, low adherence to these medications is often observed, impacting their therapeutic effect.

• Adherence to obesity medication can be affected at any phase of obesity management (weight gain, weight loss, and weight stabilization/regain) so considering the disease phase can help identify potential reasons for low adherence.

• Future initiatives to improve adherence to obesity medication should be a key focus of discussions at each opportunity with healthcare professionals, including thorough evaluation and targeted education, all in a supportive and stigma‐free manner.

1. INTRODUCTION

Overweight and obesity prevalence is increasing, and by 2035 the global prevalence in adults is projected to reach 54% (1.77 billion and 1.53 billion, respectively). In the same timeframe, it is estimated that 770 million children (age 5–19 years) will be living with overweight or obesity. ¹ Obesity is caused by a complex interplay of several factors ² : biological, genetic, psychological, social, medication use, and environmental, ³ , ⁴ with key environmental factors including education, family, agricultural, food environment, and built environment. ³ The high prevalence and complex nature of obesity mean there is a substantial need for effective and sustainable management of people living with obesity. ¹ Use of obesity medications (OMs) for the treatment of obesity is increasing and might significantly improve obesity management; ⁵ however, in order to achieve long‐term efficient management with OMs, optimal adherence to these medications is key. ⁵ , ⁶ , ⁷

2. THE NEED FOR LONG‐TERM MEDICATION IN PEOPLE LIVING WITH OBESITY

As with the treatment of other chronic diseases, effective treatment of obesity requires a long‐term, personalized, multimodal approach, which takes into account an individual's beliefs and expectations of the benefits and risks of available therapies, as well as appropriate treatment goals. ² , ⁸ , ⁹ However, achieving such comprehensive care for people living with obesity, including when prescribing OMs, may be challenging to implement, especially in the long term. ¹⁰ , ¹¹ , ¹² , ¹³ When initiating treatment in people living with obesity, a non‐judgmental, collaborative, and person‐centered framework has been recommended based on the following steps: ask permission from the patient to talk about their weight and establish their readiness for treatment; assess factors contributing to obesity and impact on the patient's health; advise the patient on treatment options (pros and cons), the benefits of health behaviors and weight reduction; agree quantifiable, achievable, and flexible health goals; assist in selecting treatments using a shared decision‐making approach; and ensure individualized follow‐up/monitoring of patients. ¹⁴

Evidence‐based obesity treatments include behavioral interventions, pharmacotherapy, and endoscopic or bariatric surgery. ¹⁵ The long‐term response to all treatment modalities for obesity, including behavioral interventions, ¹⁶ is affected by adaptive, persistent biological responses that lead to stabilization at a reduced weight and drive weight regain. ¹⁷ These include reduced satiety hormones and energy expenditure and increased hunger hormones. ¹⁷ , ¹⁸ Pharmacotherapy can be effective alongside behavioral interventions by enhancing weight loss, as well as preventing or diminishing regain of weight by counteracting many of these physiological and biological mechanisms. ⁷ , ¹⁹ Behavioral interventions require self‐regulated processes (executive function) to reduce eating, while pharmacotherapy can act to reduce both homeostatic (generated by real or perceived nutrient need) and hedonic (generated by other than nutrient need) eating, thereby supporting executive control. ²⁰ , ²¹ Long‐term pharmacotherapy in conjunction with behavioral interventions is recommended to maximize the chance of clinically relevant, persistent weight loss in people with obesity; ² , ¹⁶ , ¹⁷ , ¹⁸ , ²² , ²³ adherence to these medications is necessary to achieve this.

3. ADHERENCE TO OM AND OTHER CHRONIC DISEASE MEDICATIONS

Efficient long‐term treatment requires adherence to medication. ²⁴ , ²⁵ Adherence to medications is defined as the process by which patients take their medications as prescribed. Historically, the definition of adherence has been confused with terms such as compliance and concordance, which have been used interchangeably. Adherence is considered a more specific, appropriate, and collaborative term in comparison with the term compliance when discussing the extent to which patients take their medication appropriately, while the term concordance was introduced to describe the patient–prescriber relationship and implies a mutual agreement between the physician and patient in which the patient or their caregiver bears responsibility for the correct administration of the medication(s). ²⁵ For later mentions of adherence in the context of study data and specific studies, we have used quotation marks (i.e., “adherence”) to signify the varied definitions of medication adherence used across studies.

When assessing adherence to medication, distinct phases have been identified (Figure 1) ²⁵ :

• Initiation: when people take the first dose of a prescribed medication

• Implementation: the extent to which people's actual dosing corresponds to the prescribed dosing regimen, from initiation until the last dose

• Persistence: the duration of taking treatment between initiation and the last dose of the medication before treatment discontinuation

The World Health Organization recommends classifying the determinants of adherence through five dimensions: patient, healthcare professional (HCP), socioeconomic, medical condition, and therapy factors (Figure 2). ²⁶ More than 700 individual factors have been identified that influence adherence to chronic therapies. ²⁴

FIGURE 1.

Illustration of the process of adherence to medication. Circles with ticks denote the medication was taken as prescribed at that timepoint and the circles with crosses denote medications not taken as prescribed at that timepoint. ²⁵ Adapted from Vrijens B et al Br J Clin Pharmacol. 2012.

FIGURE 2.

The five dimensions that determine medication adherence. ²⁶ HCP, healthcare professional; Rx, prescription.

Adherence to medication, especially for chronic diseases, is important because low adherence impacts treatment efficacy, which subsequently fails to prevent severe health complications, and leads to premature deaths and increased costs. ²⁷ However, inconsistent adherence to treatments for chronic diseases is common across all therapeutic areas ²⁸ , ²⁹ and a worldwide problem. ²⁶ Medication adherence varies considerably between diseases, healthcare systems, and medications. In developed countries, adherence to long‐term therapies in the general population is around 50%. ²⁷ , ²⁸ , ²⁹

For the long‐term management of obesity, currently licensed pharmacotherapeutic options across the United States and Europe include orlistat, phentermine/topiramate (only approved for use in the United States), ¹⁴ naltrexone/bupropion, liraglutide, semaglutide, and tirzepatide. ¹⁴ , ³⁰

It is, however, challenging to gain insights in the real‐world use of “adherence” to these OMs, because overall, there is a paucity of data regarding OM “adherence” in people living with obesity. Furthermore, the different phases to assess medication “adherence,” initiation, implementation, and persistence are often combined in assessments and are measured differently across studies, making comparisons challenging. ³¹ To improve consistency and comparability between studies on medication adherence, the European Society for Patient Adherence Medication Adherence Reporting Guideline (EMERGE) is considered the gold standard for reporting medication adherence. ³² The four minimum reporting criteria that need to be reported for adherence in the EMERGE guidelines are: phases of medication adherence (Figure 1), operational definition for each phase(s), measurement of each phase(s), and results for each phase(s). ³²

Available data on OM “adherence” demonstrate wide variations in persistence between OMs; for example, in a United States–based study, persistence rates at 6 months were 18.1%, 27.3%, and 41.8% in people living with obesity using naltrexone/bupropion, phentermine/topiramate, and liraglutide, respectively. ³¹ , ³³ A separate study showed 1‐year persistence rates in people living with obesity from 40% in those using semaglutide to 10% in those using naltrexone‐bupropion. ³⁴ In a US database study that aimed to examine the trends in the prescription of OMs in people living with obesity from 2002 to 2011, the average cumulative duration of OM use was approximately 3–4 months during the 10‐year study period, with only a quarter of people living with obesity using OMs for longer than 90 days. While this might be explained by common use of amphetamine congeners, such as phentermine, which are only licensed for short‐term (12 weeks' use), ³⁵ this study found that the duration of use was similar between medications indicated for short‐term use and those without a limited recommended duration of use, such as orlistat and sibutramine. This implies there are additional important factors, other than prescription length, that determine the duration of use of OMs in people living with obesity. ³⁵

While adherence data, particularly initiation and persistence data, from clinical trials are unlikely to reflect adherence in the real world, such data can inform about the reasons for discontinuation or non‐adherence, mostly relating to adverse effects. For example, discontinuation rates, often caused by adverse effects, of the most recently approved OMs, semaglutide and tirzepatide, in people living with obesity were 7.7% and 8.8%, respectively, during the treatment period in phase 3 randomized clinical trials (RCTs). ⁶ , ⁷ But what is known in the real‐world practice is that the main reasons for discontinuation are likely to be multifactorial. ³¹

Although cross‐study comparisons should be considered with caution, a comparison of OM “adherence” with “adherence” to medication for other chronic diseases might provide additional insights. Therefore, we compared “adherence” rates to treatments across various chronic diseases at the different phases of adherence in selected recent studies (Table 1). Primary non‐adherence refers to those who, after a prescription, do not go to the pharmacy to acquire the first box of medication. This information is typically derived from integrated prescription/dispensing databases and can cause initiation to not be reached. A higher proportion of people living with obesity did not initiate therapy with OMs compared with medications for other chronic conditions, including diabetes, hypertension, hyperlipidemia, and osteoporosis. ³⁶ , ³⁷ , ³⁸ , ³⁹ , ⁴⁰ A primary non‐adherence rate of 91.1% within 60 days for people living with obesity‐prescribed OMs, including liraglutide, lorcaserin, naltrexone‐bupropion, orlistat, and phentermine‐topiramate, was reported. ³⁶ Persistence and implementation are also low in people living with obesity using OMs: A 2024 study of people taking semaglutide for obesity in the real‐world setting demonstrated that 5.7% of this population stopped treatment after the first dose, and only 13% reached the maximum dose of 2.4 mg, which is the maintenance dose studied in clinical trials. ³⁹ Persistence may also be lower in people using OMs compared with medications for the other listed chronic diseases (Table 1). ²³ , ³⁴ , ³⁸ , ⁴⁵ , ⁴⁶ Overall, these data suggest that adherence challenges are greater for people being treated for obesity with OMs compared with those being treated for other chronic diseases.

TABLE 1.

Adherence rates by stage of adherence in different chronic diseases.

Chronic disease medication	General adherence rates	Adherence at the initiation phase	Adherence at the persistence phase	Issues with the studies included in comparison
Obesity medication	15.1% exhibited “high adherence” (≥80% of the proportion of days covered) a (liraglutide) 37	91.1% exhibited primary non‐adherence within 60 days b (liraglutide, lorcaserin, naltrexone‐bupropion, orlistat, and phentermine‐topiramate) 36	58% were not persistent after ≥12 weeks (GLP‐1RAs) 5 68% had no adherence to medication after 1 year (semaglutide and liraglutide) 38 Adherence rates were: 44% at 3 months 33% at 6 months 19% at 12 months 34 (phentermine‐topiramate, naltrexone‐bupropion, orlistat, semaglutide, liraglutide) 94% adherence rate after first dose (semaglutide) 39	Non‐representative population in secondary health care data 36 Administrative claims lack detail, so context is lacking 36 Limited medications studied 37 , 38 , 39
Diabetes medication	38.5% to 93.1% had adherence (OAD alone or OAD in combination with insulin) 40 22% of studies in a systematic review exhibited high (≥80%) prevalence of adherence (OAD alone or OAD in combination with insulin) 40	46.7% exhibited primary non‐adherence (insulin) 41 11% exhibited primary non‐adherence (non‐specified anti‐diabetic) 42 10% exhibited primary non‐adherence (non‐specified anti‐hypertensive) 43	44.6% halted after 12 weeks (orlistat) 23	Single medication studied 23 Non‐representative population 41 Pharmacy claims were used as a measure of adherence and can only be estimated for patients who have purchased the drug 42
Antihypertensive medication	45.2% had no adherence (non‐specified anti‐hypertensive) 44 83.7% had no adherence (uncontrolled blood pressure, non‐specified anti‐hypertensive) 44	7% exhibited primary non‐adherence (non‐specified anti‐hypertensive) 42 3.2% exhibited primary non‐adherence (non‐specified anti‐hypertensive) 45 16% exhibited primary non‐adherence (non‐specified anti‐hypertensive) 43	16.7% halted after dispensing the therapy only once (early‐stage non‐persistence) (non‐specified anti‐hypertensive) 45 3.6% halted before 24 months after dispensing more than once (second‐stage non‐persistence) (non‐specified anti‐hypertensive) 45	Pharmacy claims were used as a measure of adherence and can only be estimated for patients who have purchased the drug 42 High levels of study heterogeneity cited in a systematic review 44 Pharmacy‐based measures of adherence cannot ensure the patient took the medication 45
Hyperlipidemia medication (cholesterol lowering)	N/A	13% exhibited primary non‐adherence (non‐specified anti‐hyperlipidemic) 42 8.5% exhibited primary non‐adherence (non‐specified anti‐hyperlipidemic) 45 25% exhibited primary non‐adherence (non‐specified anti‐hyperlipidemic) 43	21.8% halted after dispensing the therapy only once (early‐stage non‐persistence) (non‐specified anti‐hyperlipidemic) 45 5.5% halted before 24 months after dispensing more than once (second‐stage non‐persistence) (non‐specified anti‐hyperlipidemic) 45 12% discontinued within 1 year (statins) 46	Pharmacy‐based measures of adherence cannot ensure the patient took the medication 45 , 46
Osteoporosis medication	12.9–95.4% of patients had adherence to medication across 124 articles (bisphosphonates, parathyroid hormone‐related analogue, denosumab, selective estrogen receptor modulators, estrogen/progestin therapy, calcitonin, and strontium ranelate) 47	25% exhibited primary non‐adherence (non‐specified anti‐osteoporotic) 43	N/A	Predominantly Western populations studied 43 Heterogenous definitions of primary non‐adherence 43

^a The number of days was calculated for each study participant by dividing the number of days covered during the follow‐up period by 182 days (total follow‐up period in days). The number of days covered was calculated as follows: (number of prescriptions redeemed) (number of daily injections per prescription) within 6 months.

^b Primary non‐adherence was defined as no pharmacy claim for the AOM within 60 days of the date of the new prescription order as identified in electronic health record data. GLP‐1RA, glucagon‐like peptide‐1 receptor agonist; N/A, not applicable; OAD, oral antidiabetic drug.

4. DETERMINANTS OF ADHERENCE TO OM

Adherence is multifactorial, as outlined by its five dimensions (Figure 2), ²⁶ and management of adherence is the process of monitoring and supporting patients' adherence to medications by health care systems, HCPs, patients, and their social networks. ²⁵ Therefore, multiple and multi‐disciplinary determinants should be considered when identifying barriers to adherence for OMs.

Firstly, HCP expertise influences adherence in patients receiving OMs. This was illustrated by a real‐world study of patients with obesity receiving glucagon‐like peptide‐1 receptor agonists (GLP‐1RAs), in which patients prescribed the GLP‐1RA from an endocrinologist or obesity specialist were more likely to complete 12 weeks of treatment compared with a prescription from a primary care physician. ⁵ Additional barriers to initiating any obesity treatment in primary care were identified in the ACTION IO study. HCPs perceived lack of time in appointments (54%), more important issues to discuss (47%), a perception that the person with obesity is “not motivated” to lose weight (68%), a perception that the person with obesity is “not interested” in losing weight (71%), and a perception that the person with obesity does not believe they can lose weight (46%) as being important factors. ⁴⁸ The most prevalent reason given by people living with obesity for not discussing weight with their HCP was a belief that they are solely responsible for managing their weight (44%). ⁴⁸ This feeling in a person living with obesity of being solely responsible for managing their weight may cause a feeling of not being worthy of medication. The impact on adherence of patients not feeling worthy of medication was demonstrated in patients with human immunodeficiency virus receiving antiretroviral therapy. Lower antiviral medication “adherence” in patients with human immunodeficiency virus was reported compared with other viral infections because patients felt less empowered in their treatment. ⁴⁹

Weight control is an important aspect of the management of type 2 diabetes (T2D), and people living with this condition may use similar medications to those used by people living with obesity. Studies on the determinants of adherence to medications for T2D may therefore provide useful additional information on the determinants of adherence to OM. Our recommendations on improving adherence to OMs are based on unique obesity‐specific guidance, along with lessons from adherence to T2D medication.

Determinants of adherence to OM are varied, such as age, ⁵ cost, ⁵⁰ and language used in conversations about the disease ⁵¹ (Figure 3). Following recent approvals and a substantial increase in demand for OMs, medication shortages and cost/reimbursement issues are important determinants of adherence to OMs. Determinants of adherence should be (but have not been) considered according to the phases of obesity management, which include weight gain, weight loss, and weight stabilization/weight regain (Figure 4). This approach would allow evaluation of the determinants of adherence to OM in an obesity‐specific context (Figure 4). Issues at treatment initiation can include people living with obesity not feeling they are worthy of the medication, ⁵² weight stigma and not recognizing obesity as a disease or its relapsing nature. Additional determinants of adherence to OM at treatment initiation are people living with obesity considering the use of OM as “cheating,” fear of short‐ and long‐term adverse events, fear of polypharmacy, depression, and supply issues leading to delayed access to prescriptions.

FIGURE 3.

Obesity‐ and adherence‐related determinants of adherence to OM, grouped by World Health Organization dimensions. ²⁶ HCP, healthcare professional; OM, obesity medication.

FIGURE 4.

Determinants of adherence to obesity medication at initiation and persistence. The solid horizontal arrows represent when that adherence phase is taking place. The striped horizontal arrow denotes the implementation phase when OM is not being taken as prescribed between initiation and discontinuation. The solid pink horizontal arrows are examples of times when discontinuation may occur (discontinuation can occur at any time) and these relate to the dashed pink arrows in the graph. These pink arrows demonstrate that OM adherence is relevant to each phase of obesity management following initiation, with weight regain possible. OM, obesity medication.

Further categorization of the determinants of adherence to OM can be considered for the implementation phase of adherence, and include a long titration period and individual tailoring required and the complexity of taking OM in relation to mealtime for some OMs, ⁵³ factors related to the route of administration of medication, ⁵³ frequency of treatment, ⁵³ alcohol use, and family disorganization.

Persistence with OM treatment, the final and ongoing phase of adherence, also has specific determinants in obesity management. There is often a mismatch between patient‐perceived outcome targets, which may relate mainly to weight loss, and clinical outcome targets, which may focus more on health outcomes or diminished risks for ill health. Differences in these outcome targets between patient and physician may lead to the patient perceiving treatment failure while the physician does not. Variability of response to OM ⁷ itself contributes to worse adherence as well as leading to differences between expectations and reality. The expectation effect describes when patients stop their medication because their results are different than they expected in terms of weight loss or another treatment target. In patients with T2D using GLP‐1RAs, those who experienced an early reduction in weight compared with those who did not have significantly greater “adherence” over 18 months, 43.3% and 38.0% (p < 0.001), respectively. ⁵⁴ , ⁵⁵ The perceived long‐dose effect, i.e., people living with obesity not regaining weight immediately after stopping treatment, affects persistence with OM. Further determinants of non‐persistence include people living with obesity or physicians not understanding the chronicity of obesity potentially due to a lack of education, a view that people living with obesity should know how to control their weight, misunderstanding of the physiology of the weight plateau phase and attributing it to drug resistance or failure, adverse effects and/or concern over the safety of long‐term OM use, treatment fatigue potentially due to regular dosing, no establishment or disruption of a habit for taking medication/failing to use the medication as part of a routine, pregnancy, and intercurrent events (e.g., weddings) where restricted eating may be perceived as antisocial.

The above determinants of adherence to OMs can also be attributed to obesity‐related barriers or adherence‐related barriers, which may be important when developing obesity‐ or OM‐specific effective interventions to improve OM adherence (Figure 3). We identified a range of obesity‐related barriers, outlining the unique challenges. Awareness and knowledge of these determinants, especially when considered within a framework, will aid HCPs in understanding the obstacles their patients face when prescribing OM.

5. THE FOUNDATIONS FOR IMPROVING ADHERENCE TO OM

To optimize the effectiveness of approaches to improve OM adherence and subsequently health‐related outcomes, each phase of adherence requires specific considerations. An umbrella review exploring factors of adherence to weight‐loss interventions in people living with obesity identified the importance of personalizing interventions, and of demographic and self‐monitoring factors, to improve adherence. ⁵⁶ These concepts should be considered when designing strategies to improve adherence specifically to OM in people living with obesity. Improving clinical study designs and/or reporting of RCTs for interventions aimed at improving adherence can also help to increase adherence, as illustrated by an analysis of T2D medication. The T2D analysis concluded that future RCTs need transparent and comprehensive descriptions of the behavioral change technique used, as well as the intervention characteristics. ⁵⁷ , ⁵⁸ These lessons from T2D can be transferred to OM adherence studies to ensure appropriate interventions can be implemented.

Education and counseling for patients to optimize medication adherence have been previously shown to be effective for people with both diabetes and hypertension. ⁵⁹ HCPs and patient education on obesity, its underlying pathophysiology, and OM mechanisms of action are important to raise awareness of why OMs are required, ultimately leading to greater adherence to OMs ⁶⁰ and lower stigma related to obesity treatment. An example of this is the Diabetes Remote Intervention to ImproVe use of Evidence‐based medications (DRIVE) trial, conducted in the United States in people with T2D at high CV and/or kidney risk, which showed that both prescription and uptake to GLP‐1RAs and sodium–glucose cotransporter‐2 inhibitors were improved following a virtual patient education program. Virtual team‐based educational approaches have also been shown to be effective for improving medication adherence in other chronic diseases. ⁶¹ The DRIVE trial was partly pharmacist‐led, ⁶¹ and pharmacists have been shown to be effective targets for improving medication adherence ⁵⁷ , ⁶² ; however, this is country‐specific and may not be appropriate for countries where pharmacists have a lesser role in medication discussions. As well as patient‐focused approaches, public‐facing campaigns to promote understanding of obesity as a chronic disease and the long‐term health benefits of OM use are essential to improve OM adherence. The importance of these public‐facing programs is highlighted by friends and social networks being integral to adherence to weight‐loss programs. ⁶³ Public‐facing campaigns should aim to address the stigma related to seeking and using OM and reduce the narrative that it is the “easy way out.”

Communication between people living with obesity and HCPs, and the timing of this communication, can also impact adherence to OMs. HCPs must acknowledge that initiating the use of OMs should not be something the patient has to earn. Then, HCPs must understand that adherence poses problems for all human beings, so they should proactively take action to address these issues with their patients. Encouragement around medication adherence through support and clear communication, for example, from HCPs on the importance of adherence, can improve adherence to OM. ⁶⁰ People living with obesity mostly appreciate HCPs initiating the conversation about obesity management, ²⁶ , ⁴⁸ but the attitudes and language used by HCPs when engaging with people living with obesity can also affect their adherence to OM. ⁵² An open and collaborative dialogue is imperative to achieve a person's obesity treatment goals and initiate OM appropriately. For example, during the treatment initiation phase, many patients are in a highly reflective motivational stage and need specific help to learn how to use the medication as part of a routine behavioral habit, thus strengthening their adherence. ⁶⁰

Initiatives focusing on policy and health systems will also form the foundation for improving adherence to OM. Overall, the following combined enablers are recommended to improve medication adherence at a system level: acknowledge, inform, incentivize, and steer and support. ²⁷ This should include stronger and clearer recommendations for the use of OMs in guidelines to ensure HCPs know when and how to implement OM effectively. Further work from the industry to improve accessibility through pricing, reimbursement, and supply chain policy will be important to meet the increasing demand.

Finally, telehealth and mobile app–based interventions may be effective tools to assist with patient communication to optimize OM adherence in the future. They have been shown to help improve medication adherence in patients with T2D and are therefore likely to be applicable to people living with obesity; general telemedicine interventions have already been shown to be effective in weight management. ⁶⁶ , ⁶⁷ , ⁶⁸

Lessons from bariatric surgery, T2D, and hypertension provide additional examples of strategies that may be considered in people with obesity using OMs (Table 2).

TABLE 2.

Recommendations for improving adherence, including lessons learned from adherence in bariatric surgery, T2D, and hypertension.

Adherence and clinical management	Behaviors associated with bariatric surgery 64	T2D	Hypertension 65
Interventions should be specific to the adherence phase	Increase patient engagement in aftercare appointments	Improve the design and/or reporting of randomized clinical trials for interventions aimed at improving adherence in T2D 57 , 58	Education and counselling 59
Use medications as part of a routine 60 not as something that the patient must have “earned with effort” or prior good results on weight loss	Innovate strategies to address barriers to follow‐up	Virtual team‐based educational approaches 61	Non‐judgmental communication skills assessing the barriers and patient's fears
Open dialogue with no blame for non‐adherence 26	Patient education on expectations following treatment	Education and counselling 59	Engage and empower patients in a shared decision‐making process
Appropriate language 52	Address concerns on shame or believing that getting help will not make a difference when weight loss has been less than expected		Reinforce self‐monitoring of BP
Pharmacist‐based interventions may be effective in some countries 57 , 61 , 62	Facilitate contact with behavioral health experts to address negative connotations and use motivational communication		Provide positive feedback on behavioral and clinical improvements
Telehealth and app‐based learning 66 , 67 , 68	Consider using a brief screening and follow‐up monitoring of cognitive impairment as this could impact how the patient is communicated with		Avoid complex regimens and polypharmacy and use fixed‐combination pills with longer half‐life if possible
	Emerging health technologies can be used to help patients with self‐management		Assess for potential medication adverse effects
			Obtain family support and collaborate with other healthcare providers, including pharmacists

Abbreviations: BP, blood pressure; T2D, type 2 diabetes.

6. CONCLUSION

Obesity is a chronic and relapsing disease, and long‐term management of health and weight loss are important treatment goals for people living with obesity. OMs are effective at reducing weight and maintaining weight loss; however, weight regain is extremely likely to occur if the medication is stopped, highlighting the importance of OM adherence. However, non‐adherence is common in chronic diseases and seems to be particularly prevalent in people living with obesity using OMs, especially at the treatment initiation phase. To identify specific determinants of OM adherence, this review considered the phases of adherence (initiation, implementation, and persistence) according to the obesity management phases (weight gain, weight loss, and weight stabilization/regain). This framework will assist with developing interventions to improve OM adherence.

Communicating openly and informatively with people living with obesity can help to reduce the barriers to OM adherence, especially when also educating people about this chronic disease and the benefits of treatments and reducing stigma around both adherence and obesity. Future studies are warranted to consider outlining thorough, practical, and personalized steps for implementing the current recommendations to improve adherence to OMs, targeting specific stages of adherence.

CONFLICT OF INTEREST STATEMENT

AMS declares speaker and or consulting honoraria from AstraZeneca, Boehringer Ingelheim, Currax, Eli Lilly, IMP, Johnson & Johnson, MD Briefcase, Medscape, Novo Nordisk, Oviva, Streamed Up, and Xeno Biosciences.

SB declares consulting fees from European Coalition for People Living with obesity, Novo Nordisk and Boerhinger Ingelheim, speaker honoraria from NIPC, Novo Nordisk Ireland, Apollo Endo Surgery, Safefood Ireland, Diabetes Ireland, International Medical Press, 67 Degrees Medical and Radcliffe Medical Education, support attending ASO UK, participation on an advisory board with Novo Nordisk and Boerhinger Ingelheim, and a fiduciary role in Obesity Institute Leeds Beckett PPI.

MC declares honoraria from Novo Nordisk, Consilient Health, Obesity Canada, NIPC, Med Learning Group, Royal College of General Practice, Johnson & Johnson; participation on a data safety monitoring board or advisory board with Novo Nordisk and Johnson & Johnson; an unpaid committee member for the Association for the Study of Obesity Ireland (ASOI); founder of My Best Weight Clinic, Obesity Clinical Lead at the Irish College of GPs; and a member of the Irish National Obesity Management Clinical Advisory Group.

NF declares receiving consulting fees from EVA Pharma and STRUCTURE Therapeutics, honoraria from Novo Nordisk (Brazil) for a lecture; support from the World Obesity Federation to attend and receive a prize at the International Congress on Obesity 2024; participation on a data safety monitoring board for the ByBandSleeve trial and EMBIO trial, which both ended 2023; unpaid chair for the World Obesity Federation Publications Committee and unpaid chair TSC for DIAMOND; and receiving Novo Nordisk employee shares.

GL declares honoraria for an advisor and/or lectures from Novo Nordisk Israel, Eli Lilly, and CTS Israel; serving as a PI/investigator in institutional clinical trials where payments were made to Sheba Medical Center from Novo Nordisk/Novo Nordisk Israel, Eli Lilly, and Rhythm Pharmaceuticals; consulting fees from Novo Nordisk/Novo Nordisk Israel and Eli Lilly; honoraria for lectures from Novo Nordisk Israel, Eli Lilly, and CTS Israel; payment for expert testimony and support for attending meetings from Novo Nordisk Israel; and payment for attending advisory boards from Novo Nordisk, Novo Nordisk Israel and Eli Lilly.

VVV declares an unrestricted grant from Novo Nordisk to INCMNSZ to provide training in obesity for health professionals, from which VVV received honorarium for being the head teacher, and also to Obesidades for carrying out an awareness campaign, a research project and for social activities; honoraria from Novo Nordisk (Global, México) and Eli Lilly (México) for expert advice on educational projects and campaigns related to obesity; honoraria and travel support for lectures, presentations in conferences, and educational events from Novo Nordisk (Global, México y LATAM), Eli Lilly (México), and Merck; travel support from Novo Nordisk, through Obesity Policy Engagement Network (OPEN) and conference attendance for the European Congress on Obesity (ECO) in 2022 and 2023; travel support from the World Obesity Federation and conference attendance for the International Congress on Obesity (ICO) in 2024; participation in an advisory board on adherence to medications for obesity from Novo Nordisk; and an unpaid position of Chair of Obesidades Mexico.

BV declares participation in an advisory board on adherence to medications for obesity from Novo Nordisk.

Sharma AM, Birney S, Crotty M, et al. Determinants of adherence to obesity medication: A narrative review. Obesity Reviews. 2025;26(5):e13885. doi: 10.1111/obr.13885