Haverford College
Haverford Scholarship
Faculty Publications
Psychology
2011
A two-year randomized trial of obesity treatment in
primary care practice
Thomas A. Wadden
Haverford College, twadden@haverford.edu
Follow this and additional works at: http://scholarship.haverford.edu/psychology_facpubs
Repository Citation
Wadden TA, Volger S, Sarwer DB, et al. A two-year randomized trial of obesity treatment in primary care practice. N Eng J Med.
2011;365:1969-79.
This Journal Article is brought to you for free and open access by the Psychology at Haverford Scholarship. It has been accepted for inclusion in Faculty
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The
n e w e ng l a n d j o u r na l
of
m e dic i n e
original article
A Two-Year Randomized Trial of Obesity
Treatment in Primary Care Practice
Thomas A. Wadden, Ph.D., Sheri Volger, R.D., M.S., David B. Sarwer, Ph.D.,
Marion L. Vetter, M.D., R.D., Adam G. Tsai, M.D., Robert I. Berkowitz, M.D.,
Shiriki Kumanyika, Ph.D., M.P.H., Kathryn H. Schmitz, Ph.D., M.P.H.,
Lisa K. Diewald, R.D., M.S., Ronald Barg, M.D., Jesse Chittams, M.S.,
and Reneé H. Moore, Ph.D.
A bs t r ac t
Background
Calls for primary care providers (PCPs) to offer obese patients behavioral weight-loss
counseling have not been accompanied by adequate guidance on how such care could
be delivered. This randomized trial compared weight loss during a 2-year period in
response to three lifestyle interventions, all delivered by PCPs in collaboration with
auxiliary health professionals (lifestyle coaches) in their practices.
Methods
We randomly assigned 390 obese adults in six primary care practices to one of three
types of intervention: usual care, consisting of quarterly PCP visits that included education about weight management; brief lifestyle counseling, consisting of quarterly
PCP visits combined with brief monthly sessions with lifestyle coaches who instructed participants about behavioral weight control; or enhanced brief lifestyle counseling,
which provided the same care as described for the previous intervention but included
meal replacements or weight-loss medication (orlistat or sibutramine), chosen by the
participants in consultation with the PCPs, to potentially increase weight loss.
Results
Of the 390 participants, 86% completed the 2-year trial, at which time, the mean (±SE)
weight loss with usual care, brief lifestyle counseling, and enhanced brief lifestyle
counseling was 1.7±0.7, 2.9±0.7, and 4.6±0.7 kg, respectively. Initial weight decreased
at least 5% in 21.5%, 26.0%, and 34.9% of the participants in the three groups, respectively. Enhanced lifestyle counseling was superior to usual care on both these measures
of success (P = 0.003 and P = 0.02, respectively), with no other significant differences
among the groups. The benefits of enhanced lifestyle counseling remained even after
participants given sibutramine were excluded from the analyses. There were no significant differences between the intervention groups in the occurrence of serious
adverse events.
From the Departments of Psychiatry
(T.A.W., S.V., D.B.S., M.L.V., R.I.B., L.K.D.,
R.H.M.), Surgery (D.B.S.), and Medicine
(M.L.V.) and the Center for Clinical Epidemiology and Biostatistics (S.K., K.H.S., J.C.,
R.H.M.), the Perelman School of Medicine at the University of Pennsylvania;
the Department of Child and Adolescent
Psychiatry, Children’s Hospital of Philadelphia (R.I.B.); and Penn Medicine,
Clinical Care Associates (R.B.) — all in
Philadelphia; and the Division of General
Internal Medicine and Center for Human
Nutrition, University of Colorado, Aurora
(A.G.T.). Address reprint requests to
Dr. Wadden at the University of Pennsylvania, 3535 Market St., Suite 3029, Philadelphia, PA 19104, or at wadden@mail.med
.upenn.edu.
This article (10.1056/NEJMoa1109220)
was published on November 14, 2011, at
NEJM.org.
N Engl J Med 2011;365:1969-79.
Copyright © 2011 Massachusetts Medical Society.
Conclusions
Enhanced weight-loss counseling helps about one third of obese patients achieve longterm, clinically meaningful weight loss. (Funded by the National Heart, Lung, and
Blood Institute; POWER-UP ClinicalTrials.gov number, NCT00826774.)
n engl j med 365;21
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1969
The
n e w e ng l a n d j o u r na l
I
nvestigators are searching for new
approaches to the treatment of obesity during
routine medical visits.1-4 Trials in which primary care providers (PCPs) offer counseling about diet
and activity (i.e., lifestyle counseling) have led to
weight loss of 2.5 kg or less over study periods
ranging from 6 to 18 months.5-7 Limited treatment
contact is probably responsible for this modest degree of weight loss.1 Given the demands on providers’ time, an increase in the frequency of PCP
counseling does not appear to be feasible.8 As an
alternative, Tsai et al.9 trained medical assistants
to deliver individual lifestyle counseling with the
use of an abbreviated version of the Diabetes Prevention Program.10 Overweight patients who received eight brief counseling sessions (and met
quarterly with their PCP to manage coexisting illnesses) lost 4.4 kg in 6 months, as compared with
0.9 kg for the patients in the control group, who
were limited to quarterly PCP visits.
The present study expanded on this pilot investigation by assessing brief lifestyle counseling delivered monthly (primarily by medical assistants) in
a 2-year, randomized trial conducted in the primary care setting. In addition to comparing the
effectiveness of lifestyle counseling versus usual
care, the study included a third intervention that
was designed to increase weight loss by enhancing
lifestyle modification with liquid meal replacements or with weight-loss medication, as suggested by a treatment algorithm.11 Both orlistat
(GlaxoSmithKline) and sibutramine (Abbott) increase weight loss by approximately 3 to 5 kg, as
compared with placebo,12-14 and the same is true
for the addition of meal replacements to lifestyle
modification.15,16 The primary aim of the study
was to show that both brief and enhanced brief
lifestyle counseling would result in significantly
greater weight loss at 24 months than would usual
care. Secondary aims included comparing the effectiveness of the two lifestyle interventions. (Our
study began in September 2006; in October 2010,
sibutramine was removed from the market17 because of reports of an increase in cardiovascular
events among patients with preexisting cardiovascular disease.18,19)
Me thods
Study Design
of
m e dic i n e
National Heart, Lung, and Blood Institute to assess behavioral interventions for weight loss in
primary care practice.20 The trial was approved
by the university’s institutional review board, and
all participants provided written informed consent. Randomization began on January 9, 2008,
and final outcome assessments were completed on
February 11, 2011.
Participants were recruited and treated at six
primary care practices owned by Penn Medicine.
Six sites were selected from a total of 27 on the
basis of providing care to 2000 or more adults and
having at least two physicians and two auxiliary
health providers on staff. The sites (three urban
and three suburban) served a racially and economically diverse population.
The study design was proposed by six of the
authors and was finalized in collaboration with
members of the study steering committee.20 Data
were gathered by one of the authors in collaboration with research coordinators and were analyzed
by two of the authors. The lead author wrote the
first draft of the manuscript, with subsequent input from all the authors, and vouches for the completeness and accuracy of the data and analyses.
Study Participants
Eligibility criteria included an age of 21 years or
older, a body-mass index (BMI, the weight in kilograms divided by the square of the height in meters) of 30 to 50, and at least two of five components of the metabolic syndrome to increase the
likelihood that the participants would have cardiovascular risk factors.21 (These criteria are described
in detail in the study protocol, available with the
full text of this article at NEJM.org.) Exclusion criteria were recent cardiovascular disease, other medical conditions contraindicating weight loss, blood
pressure of 160/100 mm Hg or higher, medications
that substantially affect body weight (e.g., glucocorticoids), substance abuse, severe psychiatric illness
that could have affected adherence to the study,
bariatric surgery, loss of 5% or more of initial body
weight in the previous 6 months, and pregnancy or
lactation.20 Antidepressant medications were permitted except for those associated with marked
weight gain (e.g., lithium). The study was conducted according to the protocol.
Screening and Randomization
The Practice-based Opportunities for Weight Re- Participants were recruited with the use of mulduction trial at the University of Pennsylvania tiple methods, including PCP referral and self(POWER-UP) was one of three trials funded by the referral in response to in-clinic advertisements.
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Obesity Treatment in Primary Care Pr actice
Applicants completed two on-site screening visits
to provide informed consent and to be assessed
by means of standardized measures of height,
weight, and cardiovascular risk factors. Participants
were randomly assigned to interventions (in equal
numbers) with the use of a computer-generated
algorithm that was operated by the Investigational
Drug Service at the University of Pennsylvania. Assignments were stratified by clinic, with randomly
varied block sizes (3, 6, or 9).
Interventions
All participants were prescribed the same goals
with respect to diet and physical activity but were
provided with different levels of support to achieve
them (as described in the Supplementary Appendix,
available at NEJM.org, and the study protocol). Participants whose weight was less than 113.4 kg were
prescribed a balanced diet of 1200 to 1500 kcal per
day (1500 to 1800 kcal per day for participants who
weighed 113.4 kg or more), which consisted of
approximately 15 to 20% kcal from protein, 20 to
35% kcal from fat, and the remainder from carbohydrate. All participants were instructed to gradually increase their physical activity to 180 minutes
per week and were given a pedometer, a caloriecounting book,22 and handouts from Aim for a
Healthy Weight.23
Usual Care
Participants assigned to usual care were scheduled
for quarterly PCP visits during the 24 months of
the study to address coexisting illnesses. At each
visit, the PCP spent approximately 5 to 7 minutes
reviewing the participant’s weight change and
discussing the information provided in the handouts.23 The PCPs followed written protocols and
were instructed not to provide specific behavioral
strategies for changing eating and activity habits.
Brief Lifestyle Counseling
Participants assigned to brief lifestyle counseling
were scheduled for the same quarterly PCP visits
as the usual-care group but also spent 10 to 15
minutes each month with an auxiliary health care
provider (medical assistant), referred to as a lifestyle
coach, who delivered treatment by following abbreviated lessons from the Diabetes Prevention Program.9,10,24 Visits began with a weigh-in and then a
review of participants’ recording of food intake,
physical activity, and other goals prescribed in sequential monthly handouts (as listed in the Supplementary Appendix). For month 1 only, participants
n engl j med 365;21
had two counseling visits to instruct them about
how to record food and calorie intake in diaries
provided. In year 2, they were permitted, every
other month, to complete counseling visits by
telephone (although <5% of visits were made by
telephone).
Enhanced Brief Lifestyle Counseling
Participants assigned to enhanced lifestyle counseling had the same PCP and counseling visits as
those assigned to brief lifestyle counseling. However, in consultation with their PCP, they also chose
to take sibutramine, orlistat, or meal replacements
to increase weight loss, beginning 1 month after
treatment began. (Participants were allowed to
choose among these options in order to make the
additional treatment acceptable to them and also
to reflect the way such interventions are most likely
be selected in the primary care setting.) Sibutramine was provided at a dose of 10 mg per day, with
the option of increasing the dose to 15 mg per day
after 6 months if blood pressure and pulse measurements were within acceptable ranges.25 Orlistat
was provided at a dose of 60 mg per meal,26 with
the option of increasing the dose to 120 mg after
6 months. Participants who chose meal replacements were instructed to replace two meals and
one snack each day with shakes or meal bars
(Slim-Fast, Unilever) for the first 4 months and
to replace one meal and one snack each day for
the remainder of the study.27 (Both orlistat and the
meal-replacement products were donated by the
respective manufacturers, which had no role in
the design of the study, data collection and analysis, or preparation of the manuscript.) Participants
were allowed only one enhancement at a time (i.e.,
medication or meal replacements, all of which were
provided without charge) but could switch between them with the approval of their PCP. After
sibutramine was removed from the market, participants who took this medication switched to
either meal replacements or orlistat. (This option
was also offered in November 2009 after the Food
and Drug Administration [FDA] issued an alert
concerning the safety of sibutramine.)
PCP s and Lifestyle Coaches
Thirty of 31 PCPs across the six sites participated
as study providers; only 1 had considerable weightmanagement experience. Two or three lifestyle
coaches were identified at each site on the basis of
their good rapport with patients; none had experience with weight management, and none had to
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1971
The
n e w e ng l a n d j o u r na l
meet a body-mass index requirement to serve as a
coach. Delivery of the interventions was standardized across sites with the use of detailed protocols.
The year before the intervention began, study staff
provided 6 to 8 hours of training to PCPs and lifestyle coaches. All providers were certified in intervention delivery at baseline and were recertified
at 6-month intervals, according to previously described methods.27 Throughout the trial, the study
staff met with PCPs and coaches (for 30 to 60 minutes) approximately quarterly and monthly, respectively, to review protocol implementation.
Outcomes and Assessments
The primary outcome was the change in body
weight at month 24 in each of the lifestyle-counseling groups as compared with the usual-care group.
Secondary outcomes included weight change in the
enhanced-lifestyle-counseling group as compared
with weight change in the lifestyle-counseling
group and the percentages of participants in each
of the three groups whose initial weight was decreased by 5% or more at 12 and 24 months and by
10% or more at 12 and 24 months. Weight was
measured by a certified staff member at baseline
and at 6, 12, 18, and 24 months with the use of a
digital scale (Tanita BWB-800). Waist circumference, blood pressure, and fasting levels of blood
glucose, triglycerides, and cholesterol (total, highdensity lipoprotein [HDL], and low-density lipoprotein [LDL]) were assessed at baseline and at
months 6, 12, and 24 with the use of standardized methods described previously25 (and in the
protocol).
Statistical Analysis
Changes in weight in the intention-to-treat
population were compared with the use of repeatedmeasures linear mixed-effects models (for continuous outcomes) and generalized-estimating-equation models (for categorical outcomes), which
controlled for initial weight, age, sex, race or ethnic
group, and study site. The study had 80% power
to detect a 2.75-kg difference in weight change at
month 24 between the usual-care and brief-lifestyle-counseling groups and between the usualcare and enhanced-lifestyle-counseling groups.
Holm’s procedure28 was used to adjust for multiple comparisons and to identify significant differences in at least one of the two between-group
comparisons (P = 0.025). For analyses of secondary
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n engl j med 365;21
of
m e dic i n e
outcomes, a P value of 0.05 or less was considered
to indicate statistical significance.
R e sult s
Baseline Characteristics of the Study
Participants
The participants included 311 women (79.7%) and
79 men with a mean (±SD) age of 51.5±11.5 years,
a mean body weight of 107.7±18.3 kg, and a mean
BMI of 38.5±4.7 (Table 1). Nearly 95% had completed high school or above; 59.0% identified
themselves as white, 38.5% as black, and 4.6% as
Hispanic. Participants who received enhanced lifestyle counseling weighed significantly less than
those who received usual care (P = 0.02), a difference addressed in the analyses by the a priori decision to control for initial weight.
Approximately 86% of the participants in each
group had their weight measured at 24 months
(Fig. 1). Reasons for missed visits at the 24-month
assessment included withdrawal from the study
(3 participants), censoring of data because of
pregnancy (1 participant) and bariatric surgery
(1 participant), and loss to follow-up (49 participants).
Weight Loss
Intention-to-Treat Population
At month 24, the mean (±SE) weight loss among
participants assigned to usual care, those assigned
to brief lifestyle counseling, and those assigned to
enhanced lifestyle counseling was 1.7±0.7, 2.9±0.7,
and 4.6±0.7 kg, respectively. Enhanced lifestyle
counseling resulted in significantly greater weight
loss than did usual care (Table 2), whereas other
between-group differences were not significant.
(Sensitivity analyses, in which multiple imputation
was used to assess the effects of missing data,
yielded similar results.) Weight losses in all three
groups differed significantly from one another at
month 6, and the maximum weight loss was generally reached at month 12 (Table 2). The percent
reduction in initial weight is shown in Figure 2
and Table 2; changes in the BMI are also shown
in Table 2.
At baseline, participants who received enhanced
lifestyle counseling chose one of three additional
treatment enhancements: meal replacements
(67 participants), sibutramine (38), or orlistat (24).
An intention-to-treat analysis, based on partici-
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Obesity Treatment in Primary Care Pr actice
Table 1. Baseline Characteristics of the Participants.*
Usual Care
(N = 130)
Brief Lifestyle
Counseling
(N = 131)
Enhanced Brief
Lifestyle Counseling
(N = 129)
Total
(N = 390)
Female
98 (75.4)
110 (84.0)
103 (79.8)
311 (79.7)
Male
32 (24.6)
21 (16.0)
26 (20.2)
79 (20.3)
White
81 (62.3)
75 (57.3)
74 (57.4)
230 (59.0)
Black
46 (35.4)
52 (39.7)
52 (40.3)
150 (38.5)
Asian
2 (1.5)
0
2 (1.6)
4 (1.0)
More than one race
1 (0.8)
4 (3.1)
1 (0.8)
6 (1.5)
Characteristic
Sex — no. of patients (%)
Race or ethnic group — no. of patients (%)†
Self-reported Hispanic
Yes
6 (4.6)
6 (4.6)
6 (4.7)
18 (4.6)
No
124 (95.4)
125 (95.4)
123 (95.3)
372 (95.4)
10 (7.7)
5 (3.8)
6 (4.7)
21 (5.4)
Education — no. of patients (%)
Less than high school
High school
25 (19.2)
27 (20.6)
26 (20.2)
78 (20.0)
Some college or associate’s degree
43 (33.1)
50 (38.2)
48 (37.2)
141 (36.2)
Bachelor’s degree
29 (22.3)
26 (19.8)
27 (20.9)
82 (21.0)
Graduate or professional degree
23 (17.7)
23 (17.6)
22 (17.1)
68 (17.4)
51.7±12.1
52.0±12.2
51.0±10.1
51.5±11.5
Weight — kg‡
Age — yr
111.2±20.0
106.3±17.3
105.4±17.2
107.7±18.3
Height — cm
168.5±8.7
165.9±8.6
166.9±8.6
167.1±8.7
39.0±4.8
38.5±4.6
37.8±4.7
38.5±4.7
Body-mass index§
Waist circumference — cm‡
119.8±13.9
117.1±11.9
115.9±11.7
117.6±12.6
Triglycerides — mg/dl
120.5±58.9
120.7±69.5
111.5±59.4
117.5±62.7
Low-density lipoprotein
112.1±38.7
116.0±31.0
118.1±31.3
115.4±33.8
High-density lipoprotein
44.0±12.7
45.4±12.9
48.6±14.9
46.0±13.6
Cholesterol — mg/dl
Total
181.7±46.8
185.5±35.9
189.1±35.5
185.5±39.7
112.3±40.1
106.2±32.2
96.3±22.5
104.9±32.9
Systolic
120.9±18.4
122.8±15.6
120.5±14.7
121.4±16.3
Diastolic
76.0±10.4
75.9±11.3
76.5±9.7
76.2±10.4
Hypertension
92 (70.8)
93 (71.0)
92 (71.3)
277 (71.0)
Diabetes mellitus
29 (22.3)
26 (19.8)
16 (12.4)
71 (18.2)
Hypercholesterolemia
78 (60.0)
93 (71.0)
82 (63.6)
253 (64.9)
Fasting glucose — mg/dl‡
Blood pressure — mm Hg
Medical conditions — no. of patients (%)
* Plus–minus values are means ±SD. P>0.05 for all comparisons except as otherwise noted. To convert the values for triglycerides to millimoles per liter, multiply by 0.01129. To convert the values for cholesterol to millimoles per liter, multiply by 0.02586. To convert the values for glucose to millimoles per liter, multiply by 0.05551.
† Race and Hispanic ethnic group were self-reported.
‡ P<0.05 for the comparison between the usual-care group and the enhanced-lifestyle-counseling group.
§ The body-mass index is the weight in kilograms divided by the square of the height in meters.
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1973
The
n e w e ng l a n d j o u r na l
of
m e dic i n e
1196 Participants were prescreened for eligibility
650 Were excluded
18 Withdrew
528 Underwent in-person screening
104 Were excluded
37 Did not meet criteria for metabolic syndrome
15 Had medical or psychiatric reason
10 Had BMI >50
5 Had BMI <30
6 Lost ≥5% of body weight
3 Were taking medication
23 Did not have time
5 Had other reasons
34 Were eligible but withdrew
390 Underwent randomization
130 Were assigned to usual care
131 Were assigned to brief
lifestyle counseling
129 Were assigned to enhanced
brief lifestyle counseling
112 Had weight measured
at 6-mo assessment
109 Had weight measured
at 6-mo assessment
118 Had weight measured
at 6-mo assessment
109 Had weight measured
at 12-mo assessment
112 Had weight measured
at 12-mo assessment
111 Had weight measured
at 12-mo assessment
105 Had weight measured
at 18-mo assessment
98 Had weight measured
at 18-mo assessment
101 Had weight measured
at 18-mo assessment
110 Had weight measured at 24-mo
assessment
20 Missed visit
19 Were lost to follow-up
1 Withdrew from study
130 Were included in primary analysis
112 Had weight measured at 24-mo
assessment
19 Missed visit
16 Were lost to follow-up
2 Withdrew from study
1 Underwent bariatric surgery
(data censored)
114 Had weight measured at 24-mo
assessment
15 Missed visit
14 Were lost to follow-up
1 Was pregnant (data censored)
129 Were included in primary analysis
131 Were included in primary analysis
Figure 1. Screening, Randomization, and Assessments of Study Participants.
Of the 129 participants randomly assigned to enhanced brief lifestyle counseling, 67, 38, and 24 initially chose to use
meal replacements, sibutramine, and orlistat, respectively. BMI denotes body-mass index (the weight in kilograms
divided by the square of the height in meters).
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Obesity Treatment in Primary Care Pr actice
Table 2. Estimated Mean Weight Loss, Percent Reduction in Body Weight, and Change in Body-Mass Index over a 24-Month Period
in the Intention-to-Treat Population.*
Usual Care
(N = 130)
Variable
Brief LC
(N = 131)
Enhanced Brief LC
(N = 129)
P Value
Brief LC
vs. Usual Care
Enhanced Brief LC Enhanced Brief LC
vs. Usual Care
vs. Brief LC
Change in body weight (kg)
At month 6
−2.0±0.5
−3.5±0.5
−6.6±0.5
0.03
<0.001
<0.001
At month 12
−2.3±0.6
−3.4±0.6
−7.1±0.6
0.23
<0.001
<0.001
At month 18
−1.9±0.7
−3.0±0.7
−5.8±0.7
0.22
<0.001
0.004
At month 24
−1.7±0.7
−2.9±0.7
−4.6±0.7
0.22
0.003
0.08
At month 6
−1.8±0.5
−3.5±0.5
−6.5±0.5
0.005
<0.001
<0.001
At month 12
−2.1±0.6
−3.5±0.6
−7.0±0.6
0.08
<0.001
<0.001
At month 18
−1.7±0.7
−3.1±0.7
−5.8±0.6
0.10
<0.001
0.002
At month 24
−1.6±0.6
−2.9±0.7
−4.7±0.6
0.12
<0.001
0.04
At month 6
−0.7±0.2
−1.3±0.2
−2.4±0.2
0.02
<0.001
<0.001
At month 12
−0.8±0.2
−1.3±0.2
−2.5±0.2
0.18
<0.001
<0.001
At month 18
−0.7±0.2
−1.1±0.2
−2.1±0.2
0.17
<0.001
0.005
At month 24
−0.6±0.2
−0.9±0.2
−1.6±0.2
0.27
0.003
0.05
Change in weight (%)
Change in body-mass index†
* Plus–minus values are means ±SE. The data for the three intervention groups are model-based estimates for the intention-to-treat population.
The numbers of participants for whom weight measurements were available at 6, 12, 18, and 24 months were as follows: for the group that received usual care, 112, 109, 105, and 110 participants, respectively; for the group that received brief lifestyle counseling (LC), 109, 112, 98, and
112 participants, respectively; and for the group that received enhanced brief LC, 118, 111, 101, and 114 participants, respectively.
pants’ initial choice of enhancement, revealed a
mean weight loss of 3.9±1.0, 5.5±1.3, and 4.6±1.7
kg in these three subgroups, respectively, at month
24, with no significant differences among them.
Eleven participants (16%) who initially chose meal
replacements switched to a different enhancement,
as did 15 participants (39%) who chose sibutramine (including 9 in whom the drug was withdrawn in response to the FDA’s actions) and
8 participants (33%) who chose orlistat. For all the
sibutramine-treated participants, the assessment
at month 6 preceded the withdrawal of the medication from the market. Weight losses at this time
point and the results of other assessments can be
found in Figure 1 in the Supplementary Appendix.
month 24, which was significantly greater than the
loss for those who received usual care (1.7±0.7 kg)
but did not differ significantly from the weight
loss for those who received brief lifestyle counseling (2.9±0.7 kg). Table 1 in the Supplementary Appendix shows weight loss in this modified intention-to-treat population. An analysis of weight loss
in the 66 participants in the enhanced-lifestylecounseling group who used meal replacements
(without exposure to sibutramine) for most of the
trial revealed a loss of 4.1±0.9 kg at month 24,
which was significantly greater than that in the
usual-care group (P = 0.04) but did not differ significantly from the weight loss in the brief-lifestyle-counseling group (P = 0.30).
Modified Intention-to-Treat Population
Categorical Weight Loss
Weight loss at month 24 among the 129 participants who received enhanced lifestyle counseling
was reanalyzed, excluding the 44 participants who
received sibutramine at any time. The remaining 85 participants lost a mean of 4.3±0.8 kg at
Figure 3 shows categorical weight loss in the
intention-to-treat population: the percentages of
participants in the three groups whose weight
was at or below their baseline weight at months
12 and 24, the percentages of participants who had
n engl j med 365;21
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The
n e w e ng l a n d j o u r na l
m e dic i n e
Usual care
2
Usual care
(N=130)
0
−2
Brief lifestyle
counseling
(N=131)
−4
−6
Enhanced
brief lifestyle
counseling
(N=129)
−8
−10
0
6
12
18
Brief lifestyle
counseling
Enhanced brief
lifestyle counseling
A
24
P=0.03
100
P=0.02
90
Weight ≤ Baseline Weight
(% of participants)
Estimated Mean (±SE) Change
from Baseline Weight (%)
of
Months
80
70
60
70.2
72.1
67.4
59.2
58.8
53.1
50
40
30
20
10
0
Figure 2. Estimated Percent Reduction in Baseline Weight over a 24-Month
Period in the Intention-to-Treat Population.
Month 12
Month 24
B
lost 5% or more of their initial weight at months
12 and 24, and the percentages of participants
who had lost 10% or more of their initial weight
at months 12 and 24. All categorical weight losses
at 12 and 24 months were significantly greater in
the group that received enhanced lifestyle counseling than in the group that received usual care.
(Fig. 2 in the Supplementary Appendix shows the
results for the modified intention-to-treat population.)
Weight Loss ≥5% of Baseline Weight
(% of participants)
P<0.001
70
P=0.003
P=0.02
60
47.3
50
40
30
34.9
24.6
29.0
26.0
21.5
20
10
0
Month 12
Month 24
C
Attendance at Scheduled Visits
P<0.001
Changes in Cardiovascular Risk Factors
Participants who received enhanced lifestyle counseling had significantly greater improvements in
1976
n engl j med 365;21
P=0.002
Weight Loss ≥10% of Baseline
Weight (% of participants)
Participants in the usual-care, lifestyle-counseling,
and enhanced-lifestyle-counseling groups attended 71.8±28.6%, 69.0±29.1%, and 76.7±27.4% of the
8 scheduled PCP visits, respectively. The frequency
of attendance (across groups) declined from year
1 (81.7±24.9%) to year 2 (61.0±39.2%) (P<0.001).
Participants in the lifestyle-counseling group and
those in the enhanced-lifestyle-counseling group
attended 56.1±28.8% and 64.7±25.8% of the 25
scheduled coaching visits, respectively. Attendance
was higher in the enhanced-lifestyle-counseling
group than in the lifestyle-counseling group
(P = 0.01) and declined across both groups from
year 1 (72.1±25.4%) to year 2 (45.6±35.2%)
(P<0.001). Figure 3 in the Supplementary Appendix shows that for each intervention group, higher
attendance generally was associated with greater
weight loss.
50
45
40
35
30
25
20
15
10
5
0
P=0.04
P=0.006
25.6
17.8
10.7
3.9
Month 12
9.9
6.2
Month 24
Figure 3. Categorical Weight Loss at 12 and 24 Months.
Panel A shows the percentage of participants in each
group in the intention-to-treat population who were at
or below their baseline weight at months 12 and 24.
(Participants for whom data on weight were missing
were assumed to have a weight above the baseline
weight.) Panel B shows the percentage of participants
who lost 5% or more of their baseline weight, and Panel C shows the percentage of participants who lost
10% or more of their baseline weight. (The percentage
of participants who lost 5% or more of their baseline
weight includes the percentage who lost 10% or more.)
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Obesity Treatment in Primary Care Pr actice
waist circumference and in HDL cholesterol and
triglyceride levels at one or more assessments, as
compared with the other two groups (in the intention-to-treat population) (Table 2A in the Supplementary Appendix). However, this group had significantly smaller reductions in LDL cholesterol
levels at month 24. Blood pressure was essentially
unchanged from normal baseline values.
Adverse Events
A total of 73 hospitalizations for serious adverse
events were reported by participants during the
2-year trial. This included 21 events in 16 participants in the usual-care group, 26 events in 20 participants in the brief-lifestyle-counseling group,
and 26 events in 22 participants in the enhancedlifestyle-counseling group, with no significant
differences between groups (P = 0.556). There were
no deaths. (See Table 3 in the Supplementary Appendix for a list of all events according to intervention group.) Only three events — two cholecystectomies and one case of syncope — were
judged by the study physicians to be related to
the intervention. Sibutramine was discontinued
in five participants because of increases in blood
pressure (≥10 mm Hg), in a sixth participant because of tachycardia, and in a seventh because of
anxiety. Orlistat was discontinued in five participants because of gastrointestinal symptoms.
Discussion
The principal finding of this study was that PCPs,
collaborating with medical assistants, helped one
group of their obese patients lose an average of
4.7% of their initial weight at 24 months. This loss,
which was accompanied by improvements in cardiovascular risk factors, was achieved with enhanced brief lifestyle counseling, which combined
quarterly PCP visits, brief lifestyle coaching delivered monthly, and the use of meal replacements or
weight-loss medication. Thirty-five percent of the
participants assigned to this intervention lost 5% or
more of their initial weight, which is a common
criterion for clinically meaningful weight loss.11,29
Long-term weight loss in the group that received
enhanced lifestyle counseling (as well as in the
group that received brief lifestyle counseling without enhancement) was greater than weight loss
observed in other primary care trials,5-7,30,31 with
the exception of a study involving extremely obese
patients who were treated with intensive group life-
n engl j med 365;21
style modification and weight-loss medications.32
Enhanced lifestyle counseling offers a model for
treating obesity in primary care practices with the
help of regular staff members (PCPs and medical
assistants).
As compared with usual care, only the enhanced counseling led to a significant increase in
weight loss at month 24; brief counseling without
enhancement did not result in the 4-kg weight loss
expected in light of the results of the pilot study.9
Participants who received the brief lifestyle counseling attended significantly fewer coaching sessions than did those who received the enhanced
counseling, despite the fact that the same personnel delivered both interventions. In contrast,
participants who received the usual care lost
more than the expected 1 kg, probably because
the weight-management support they were given
(quarterly PCP visits, a calorie book, and a pedometer) to encourage them to remain in the study was
greater than the support that would typically be
provided in the primary care setting. Our findings
suggest that PCPs may be able to assist one fifth
of their obese patients in losing 5% or more of
body weight by providing educational materials
and briefly discussing weight management at
quarterly visits.
Our study shows that combining quarterly PCP
visits with brief monthly lifestyle coaching provided by medical assistants does not significantly
increase weight loss, as compared with PCP visits alone. The use of specialized personnel (e.g.,
registered dietitians),15 as well as more intensive
coaching (i.e., more than one session per month
for the first 3 months), as recommended by the
U.S. Preventive Services Task Force,1 could increase weight loss.33 However, both options would
have considerable financial and logistic consequences for primary care practices, and as suggested by our attendance data, participants might
not be willing to make additional office visits.
The strengths of this study include the randomized design, the provision of interventions by primary care personnel who treated obese patients
in their local practices (rather than the provision of
interventions by specialized personnel to highly
selected volunteer subjects), and the high rate of
study completion by participants (86%). Limitations included the provision of free treatment
enhancements (which may limit the generalizability of the results); the need for longer followup; and the withdrawal of sibutramine from the
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1977
The
n e w e ng l a n d j o u r na l
market, which clouded interpretation of the findings for the group of participants who received
enhanced brief lifestyle counseling. Nonetheless,
the beneficial effects of this latter approach remained even after analyses were limited to persons
who received only meal replacements or orlistat,
each of which continues to be available. The study
also confirmed the problem of weight regain despite ongoing counseling for weight-loss maintenance.34
Our data support the screening by PCPs of all
adults for obesity, as well as efforts to help
patients understand the health consequences of
excess weight and the benefits of modest weight
loss; these practices are consistent with prior recommendations.1,11 By providing enhanced lifestyle counseling, as described here, PCPs could
help a considerable minority of obese persons
achieve clinically meaningful weight loss,11,29
which they might not achieve if they were simply
told to reduce their weight on their own. The
treatment model used in this study awaits comparison with community-based approaches,24,35 as
well as with electronically delivered interventions
(including the Internet,36 mobile telephones,37
of
m e dic i n e
and telephone counseling33,38), which could result
in equivalent or greater weight loss. Although our
study has shown that primary care personnel can
provide effective weight-management support, it
has not addressed the more challenging question
of who will pay for these or related weight-loss
interventions.39
Supported by a grant (U01-HL087072) from the National Heart,
Lung, and Blood Institute.
Disclosure forms provided by the authors are available with
the full text of this article at NEJM.org.
We thank the health care providers and their patients who
participated in the study at the six primary care sites (individual
practitioners and study research coordinators at the sites are
listed in the Supplementary Appendix); Drs. Barbara Wells (project officer), Catherine Stoney (executive secretary), Jungnam Joo,
Peter Kaufmann, and Caye Loria of the National Heart, Lung, and
Blood Institute for contributing to the design and administration of the three POWER trials; Drs. David Goff (chair), Robert
Kushner, Gbenga Ogedegbe, Amelie Ramirez, Nathan Stimson,
and Barbara Tilley of the data and safety monitoring board for
overseeing the conduct of the study; Drs. Hsin-Chieh Yeh (chair)
and Gerald Jerome of the Resource Coordinating Unit at Johns
Hopkins University for logistic support; Dr. Delia West for sharing the weight-loss maintenance protocol developed by the
PRIDE (Program to Reduce Incontinence by Diet and Exercise)
Research Group; and Dr. Meghan Butryn for assistance in developing the treatment materials used by the participants and the
primary care personnel.
This article is dedicated to the memory of our dear friend and
colleague Dr. Thomas Ten Have.
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