Willingness to Take Weight Loss Medication Among Obese Primary Care Patients

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

Abstracts

• 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

Table 2 displays sequentially adjusted models examining various demographic, clinical, and QOL factors associated with willingness to take a weight loss medication.