ORIGINAL RESEARCH

Willingness to Take Weight Loss Medication Among Obese Primary Care Patients

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Christina C. Wee, MD, MPH, Erina Sugai, MD, Gianna Aliberti, and Sarah Chiodi, MSPH

From Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA.

 

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ABSTRACT

Objective: To identify patient factors associated with willingness to take daily weight loss medication and weight loss expectations using these medications.

Methods: A random sample of 331 primary care patients aged 18–65 years with a BMI ≥ 35 kg/m2 were recruited from 4 diverse primary care practices in Boston, MA. We conducted telephone interviews and chart reviews to assess patients’ willingness to take a weight loss medication and their expectations for weight loss. We used sequential logistic regression models to identify demographic, clinical, and quality of life (QOL) factors associated with this willingness.

Results: Of 331 subjects, 69% were women, 35% were white, 35% were black, and 25% were Hispanic; 249 (75%) of patients were willing to take a daily weight loss medication if recommended by their doctor but required a median weight loss of 15% to 24%; only 17% of patients were willing to take a medication for ≤ 10% weight loss. Men were significantly more willing than women (1.2 [95% CI 1.0–1.4]). Diabetes was the only comorbidity associated with willingness to consider pharmacotherapy (1.2 [1.0–1.3]) but only modestly improved model performance (C-statistic increased from 0.59 to 0.60). In contrast, lower QOL, especially low self-esteem and sex life, were stronger correlates (C-statistic 0.72).

Conclusion: A majority of obese primary care patients were willing to take a daily weight loss pill; however, most required more than 10% weight loss to consider pharmacotherapy worthwhile. Poor QOL, especially low self-esteem and poor sex life, were stronger correlates than having diabetes.

 

Key words: obesity; primary care; weight loss medication.

 

In the United States, obesity continues to be unrelentingly prevalent, affecting more than one-third of adults (34.9%) [1]. This statistic has ominous implications when considering that obesity is a risk factor for numerous chronic diseases, such as coronary heart disease, diabetes, sleep apnea, osteoarthritis, and some types of cancers [2]. Moreover, it is associated with increased risk of all-cause and cardiovascular disease mortality. Promisingly, an initial 5% to 10% weight loss over 6 months has been associated with improvement in LDL, HDL, triglycerides, glucose, hemoglobin A1C, diabetes risk, blood pressure, and medication use [2]. Therefore, although patients may not be able to achieve their ideal body weight or normal BMI, modest weight loss can still have beneficial health effects.

Weight loss medications are effective adjunctive therapies in helping patients lose up to 10% of their body weight on average when combined with diet and exercise [3–5]. There are currently 5 medications approved by the Food and Drug Administration for long-term use for weight loss: orlistat, lorcaserin, phentermine-topiramate, bupropion-naltrexone, and liraglutide. Despite their proven efficacy, there are barriers to initiating a long-term weight loss medication. Insurance reimbursement is limited for these medications, thus resulting in high out-of-pocket cost for patients that they may be unable or unwilling to pay [6]. There may also be safety concerns given that several weight loss medications, including fenfluramine, sibutramine, and rimonabant, have been withdrawn from the market because of adverse effects [7]. Thus, in deciding whether to initiate a pharmacologic weight loss regimen, patients must believe that the weight loss benefits will exceed the potential risks.

Little is known, however, about patients’ willingness to take weight loss medications or the minimum weight loss they expect to lose to make pharmacotherapy worthwhile. Only a few studies have investigated patient willingness to adopt pharmacotherapy as part of a weight loss regimen, and only one investigated obese patients in the United States [8]. In this context, we surveyed a sociodemographically diverse group of primary care patients with moderate to severe obesity to examine patient characteristics associated with willingness to pursue weight loss pharmacotherapy. We also aimed to evaluate how much weight patients expected to lose in order to make taking a daily medication worth the effort. Characterizing patients seen in primary care who are willing to adopt pharmacotherapy to lose weight may guide weight loss counseling in the primary care setting. Furthermore, determining whether patients have realistic weight loss expectations can help clinicians better counsel their patients on weight loss goals.

 

METHODS

Study Sample

We recruited 337 subjects from 4 diverse primary care practices in Boston, Massachusetts: a large hospital-based academic practice, a community practice in a working-class suburb, a community practice in an affluent suburb, and a health center serving a predominantly socially disadvantaged population. The primary goal of the parent study was to understand the preferences of patients for weight loss treatment, especially bariatric surgery. Therefore, to be included, patients needed to have a BMI ≥ 35 kg/m2 at the time of recruitment, been seen in clinic within the past year, be aged 18–65 years, and be English or Spanish speaking. By design, African-American and Hispanic patients were oversampled from an electronic list of potentially eligible patient groups so that we could examine for racial differences in treatment preferences. Study details have been previously described [9].

 

Data Collection and Measures

Trained interviewers conducted a 45- to 60-minute telephone interview with each participant in either English or Spanish. To assess willingness to use a daily weight loss medication, subjects were asked, “If your doctor recommended it, would you be willing to take a pill or medication every day in order to lose weight?” Those who answered affirmatively were then asked the minimum amount of weight they would have to lose to make taking a pill everyday worthwhile.

Subjects were also asked about demographic information (age, race, education, marital status) and comorbid health conditions commonly associated with obesity (diabetes mellitus, hypertension, asthma, obstructive sleep apnea, GERD, depression, anxiety, back pain, and cardiovascular problems). We assessed quality of life (QOL) using the Impact of Weight on Quality of Life-Lite (IWQOL-Lite), a 31-item instrument designed specifically to assess the impact of obesity on QOL capturing 5 domains (physical function, self-esteem, sexual life, public distress, and work). Subjects were asked to rate a series of statements beginning with “Because of my weight…” as “always true,” “usually true,” “sometimes true,” “rarely true,” or “never true.” Global and domain scores ranged from 0 to 100; higher scores reflected better QOL [10].

 

Data Analysis

We used descriptive statistics to characterize the proportion of subjects willing to use a daily weight loss medication and the weight loss required for patients to be willing to consider pharmacotherapy. We used a stepwise logistic model to examine demographic, QOL, and clinical factors associated with the willingness to take a weight loss medication as the outcome, with an entry criteria of P value of 0.1 and an exit criteria of 0.05. Log-Poisson distribution using the sandwich estimator was used to obtain relative risks for each significant variable. Adjusted models included age, BMI, sex, and race and any significant comorbidities. We added overall QOL score and individual QOL scores in subsequent models to examine the relative influence of overall vs. domain-specific QOL. Statistical analyses were conducted with SAS (SAS Institute, Cary, NC). We considered the change in model C-statistic when specific variables were added to the model to determine the importance of these factors in contributing to patients’ willingness to consider pharmacotherapy; larger changes in model C-statistic signifies a greater contribution.

 

RESULTS

OR_Obese_TABLE1aOf the 337 subjects enrolled in this study, 331 responded to the question “If your doctor recommended it, would you be willing to take a pill or medication every day in order to lose weight?” Of the respondents, 249 (75%) answered affirmatively. Table 1 characterizes our sample’s willingness to take a weight loss medication and factors significantly associated with willingness to take a weight loss medication prior to adjustment. The median weight loss required by patients ranged from 15% to 24% of body weight depending on the patient subgroup. Only 17% of patients overall were willing to take a medication for 10% weight loss or less (ranged from 6% to 31% depending on subgroup).

Table 2 displays sequentially adjusted models examining various demographic, clinical, and QOL factors associated with willingness to take a weight loss medication. OR_Obese_TABLE1bWillingness did not significantly differ by BMI, sex, and race after initial adjustment (model 1). When we considered comorbidities, only diabetes and anxiety were significant correlates; however, the change in C-statistic was negligible. In contrast, overall QOL score (model 3) was significantly associated with willingness to consider pharmacotherapy and improved the model C-statistic from 0.60 to 0.65. When we considered individual QOL domains (model 4), self-esteem and sex life were the only 2 significant domains but together improved the model C-statistics to a greater extent than overall QOL. After adjustment for QOL, men were now significantly more likely than women to consider pharmacotherapy and having a diagnosis of anxiety was no longer a significant correlate.

 

OR_Obese_TABLE2DISCUSSION

In our study, we found that a large proportion (75%) of primary care patients with at least moderate obesity were willing to take a daily weight loss medication if their doctor recommended it. After full adjustment, men, those with lower quality of life (QOL), and patients with diabetes were more likely to pursue weight loss pharmacotherapy than their counterparts. Moreover, QOL appeared more important than comorbid diagnoses in contributing to whether patients would consider taking a weight loss medication. Most patients expected to lose more than 10% of their weight to make taking a daily medication worthwhile.

Few studies have examined patients’ willingness to take a medication to lose weight. Tan et al [11] found that only about half of their surveyed outpatients were likely to take a medication to lose weight; however, approximately a quarter of the patients in that study were of normal BMI. In contrast, our study interviewed patients with at least a BMI of 35 kg/m2 and the majority of these patients reported a willingness to take a weight loss medication. Nevertheless, patients appear to have unrealistic expectations of the weight loss potential of pharmacotherapy. Only a minority of patients in our study would be willing to take a weight loss medication if the weight loss was no more than 10%, a level that is more consistent with the outcomes achievable in most clinical trials of weight loss medications [12]. Prior studies have also shown that patients often have unrealistic weight loss expectations and are unable to achieve their ideal body weight using diet, exercise, or pharmacotherapy [13,14]. Doyle et al found that percentage of weight loss was the most important treatment attribute when considering weight loss pharmacotherapy when compared to cost, health improvements, side effects, diet and exercise requirements, and method of medication administration [8]. Thus it is important to educate patients on realistic goal setting and the benefits of modest weight loss when considering pharmacotherapy. The weight loss preferences expressed in our study may also influence the weight loss outcomes targets pursued in pharmaceutical development. Interestingly, after full adjustment, BMI did not correlate with willingness to take a weight loss medication. Given that all patients in our study had a BMI of ≥ 35 kg/m2, this may imply that variations beyond this BMI threshold did not significantly affect a patient’s willingness to use pharmacotherapy. In contrast, weight-related QOL was an important correlate.

Men were slightly more likely than women to be willing to take a weight loss medication, which is interesting since men have been shown to be less likely to participate in behavioral weight loss programs and diets [15]. One reason may be that many weight loss programs are delivered in group settings which may deter men from participating. Whether this hypothetical willingness to undergo pharmacotherapy would translate to actual use is unclear, especially since there are barriers to pharmacotherapy including out-of-pocket costs. In a prior study in the United Kingdom, women were more likely to have reported prior weight loss medication use than men [16].

Our study did not find differences in willingness to pursue weight loss medication by race or educational attainment. This is consistent with our prior work demonstrating that racial and ethnic minorities were no less likely to consider bariatric surgery if the treatment were recommended by their doctor [9]. However, our other work did suggest that clinicians may be less likely to recommend bariatric surgery to their medically eligible minority patients as compared to their Caucasian patients. Whether this may be the case for pharmacotherapy is unclear since this was not explicitly queried in our current study [9].

Our study also found that patients with diabetes but not other comorbidities were more likely to consider weight loss medication after adjusting for QOL. This may reflect a stronger link between diabetes and obesity perceived by patients. Our result is consistent with our earlier data showing that diabetes but not other comorbid conditions was associated with a higher likelihood of considering weight loss surgery [9]. Nevertheless, having diabetes contributed only modestly to the variation in patient preferences regarding pharmacotherapy as reflected by the trivial change in model C-statistic when diabetes status was added to the model.

In contrast, lower QOL scores, especially in the domains of self-esteem and sex life, were associated with increased willingness to take a weight loss medication and appeared to be a stronger predictor than individual comorbidities. This is consistent with other studies showing that patients seeking treatment for obesity tend to have lower health-related QOL [9,17]. Our findings are also consistent with our previous research demonstrating that impairments in specific QOL domains are often more important to patients and stronger drivers of diminished well-being than measures of overall QOL [18]. Hence, given their importance to patients, clinicians need to consider QOL benefits when counseling patients about the risks and benefits of various obesity treatments.

This study is the first to our knowledge to systematically characterize demographic factors associated with the likelihood of primary care patients with obesity considering weight loss pharmacotherapy. This information may aid outpatient weight loss counseling by increasing awareness of gender and patient specific preferences. The fact that many patients with obesity appear to be interested in pursuing weight loss medication may also support public health initiatives in providing equitable access to weight loss pharmacotherapy. As our study characterizes patients who are willing to pursue weight loss medications, future studies may include retrospective analyses on actual use of weight loss medications among various demographic groups. Further investigation on specific reasons why patients choose whether or not to use weight loss medication may also be helpful.

This study has important limitations. The sample size was modest and potentially underpowered to detect small differences across different subgroups. Our sample was also limited to practices in Boston, which limits generalizability; although, by design, we oversampled racial and ethnic subjects to ensure diverse representation. Finally, our study examined patients’ hypothetical willingness to take weight loss medications rather than their actual adherence to treatment if offered.

 

Conclusion

In this sample of obese primary care patients, we found that the majority of patients were willing to take a daily medication to lose weight; however, patients had expectations for weight loss that far exceeded the level achievable by patients in pharmaceutical trials of these agents. Men and patients with diabetes were more likely to be willing to pursue weight loss medication; however, lower weight-related QOL, especially low self-esteem and impaired sexual function, appeared to be a stronger correlate of willingness to consider pharmacotherapy than comorbid diagnoses.

 

Corresponding author: Christina C. Wee, MD, MPH, Beth Israel Deaconess Medical Center, 330 Brookline Ave., Boston, MA 02215, cwee@bidmc.harvard.edu.

Funding/support: This study was funded by the National Institute of Diabetes, Digestive and Kidney Diseases (R01 DK073302, PI Wee). Dr. Wee is also supported by an NIH midcareer mentorship award (K24DK087932). The sponsor had no role in the design or conduct of the study; the collection, management, analysis, and interpretation of the data; or the preparation, review, or approval of the manuscript.

Financial disclosures: None reported.

 

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