Weight loss intervention adherence and factors promoting adherence: a meta-analysis

Figures & data

Figure 1 Flow diagram for included studies.

Table 1 Methodology checklist for experimental designs

Authors:
Study title:
	Yes	No
A. Research question and design
1. Was there a clear research question and was this important and sensible?
2. If the study was nonrandomized, could a randomized controlled design have been used?
B. Baseline comparability of groups
3. [RCTs only]: Was allocation adequately concealed by a rigorous method (eg, random number)?
4. Were appropriate measures of baseline characteristics taken in all groups before the intervention and were study groups shown to be comparable in all characteristics likely to influence outcome?
C. Outcome measures
5. Was the primary outcome measure valid (ie, do two independent raters agree that this was a sensible and reasonable measure of performance or outcome)?
6. Was the primary outcome measure reliable (ie, do two independent raters agree on the nature and extent of change)?
D. Protection against contamination
7. Is it unlikely that the control unit of allocation (professional, practice, institution, and community) received the intervention through contamination?
E. Protection against bias
8. Were outcomes measured by “blinded” observers or were they objectively verified (eg, quantitative measures recorded prospectively and independently)?
F. Follow-up
9. Was there complete follow-up of participants (ideally >80%)
10. Was follow-up continued for long enough for the primary outcome measure to show an impact and for sustainability to be demonstrated?

Note: Passing score for experimental designs =6/10.

Abbreviation: RCT, randomized controlled trial.

Table 2 Quasiexperimental designs

Authors:
Study title:
	Yes	No
A. Research question and design
1. Was there a clear research question, and was this important and sensible?
2. If the study was nonrandomized, could a randomized controlled design have been used?
B. Protection against secular changes
3. Was the intervention independent of other changes over time?
4. Were there sufficient data points to enable reliable statistical inference?
5. Was a formal statistical test for trend correctly undertaken?
C. Outcome measures
6. Was the primary outcome measure valid (ie, do two independent raters agree that this was a sensible and reasonable measure of performance or outcome)?
7. Was the primary outcome measure reliable (ie, do two independent raters agree on the nature and extent of change)?
D. Protection against detection bias
8. Was the intervention unlikely to affect data collection (eg, sources and methods of data collection were the same before and after the intervention)?
9. Were outcomes measured by “blinded” observers or were they objectively verified (eg, quantitative measures recorded prospectively and independently)?
F. Completeness of data set and follow-up
10. Does the data set cover all or most of the episodes of care (or other unit of analysis) covered by the study (ideally >80%)?
11. Was follow-up continued for long enough for the primary outcome measure to show an impact and for sustainability to be demonstrated?

Note: Passing score for quasiexperimental designs =6/11.

Table 3 Included studies in meta-analysis

Primary authors;	Study	Study	Number of study participants	Type of weight loss intervention	Adherence rate	Quality scores	Baseline BMI	Predictors of adherence	Other moderators (work place intervention, social support, financial incentive, or mandatory intervention)
Acharya et al;^Citation20 2009, USA	RCT	12 months	127	Group sessions, energy/calorie goal, and diet	Energy/calorie goal – 10% Attendance – 44% Self-monitor – 22%	6/10 pass	–	–	–
Annunziato et al;^Citation21 2009, USA	RCT	12 months	42	Diet – MR	Attendance – 70% MR – 41.5%	8/10 pass	31.9	–	–
Ard et al;^Citation22 2008, USA	Pre/post	5 months	377	Calorie reduction, diet, and PA	Attendance – 45.6% PA goal – 36.9%	8/11 pass	35.1	–	–
Austin et al;^Citation23 2013, USA	Pre/post	4 months	82	LEARN	Attendance – 48.8% Calorie goals – 64.5% Step goals – 80.9%	6/11 pass	33.0	Higher adherence: older age, increasing income, and increasing education Lower adherence: more children living at home, young age, and low socioeconomic status	Financial incentive
Bartfield et al;^Citation24 2011, USA	RCT	18 months	507	Group session, DASH diet, and exercise	Food record – 15.7% Exercise – 14% Attendance – 53.8%	7/10 pass	33.7	–	–
Befort et al;^Citation25 2008, USA	RCT	4 months	34	Diet, PA, motivational interview, and health education	Attendance – 52%	6/10 pass	39.8	–	–
Burke et al;^Citation26 2009, USA	RCT	24 months	210	Paper record, PDA, and PDA with feedback	Attendance/retention: cohort 1 (n=73) – 90% (24 months) Cohort 2 (n=63) – 76% (18 months) Cohort 3 (n=74) – 92% (6 months)	6/10 pass	33.4	–	–
Carson et al;^Citation27 2013, USA	RCT	6 months	92	Self-monitoring, goal setting, stimulus control, nutrition education, and cognitive restructuring	Attendance – 64.5% Monitoring – 62.1%	6/10 pass	38.1	Higher adherence: having a social contact	Social support
Carter et al;^Citation28 2013, UK	RCT	6 months	128	MMM smartphone app	Attendance – 61.7% MMM app – 16% (N=43)	7/10 pass	34.0	Lower adherence: higher BMI and poorer health status	–
Church et al;^Citation29 2009, USA	RCT	6 months	411	Exercise	4 kcal/kg/wk (N=139) – 99.5% 8 kcal/kg/wk (N=85) – 99.3% 12 kcal/kg/wk (N=93) – 99.2%	6/10 pass	31.7	–	–
Colley et al;^Citation30 2008, Australia	Pre/post	4 months	29	PA	PA goals – 31%	6/11 pass	36.8	Higher adherence: older age Lower adherence: higher weight	–
Das et al;^Citation31 2009, USA	RCT	12 months	38	Dietary ER	10% ER – 18% (N=9) 30% ER – 23% (n=29)	6/10 pass	28.8	–	–
Dutton et al;^Citation32 2015, USA	Pre/post	6 months	33	Primary care weight loss intervention + peer coaches	Attendance – 50% Peer calls – 40%	7/11 pass	42.9	–	Social support and financial incentive
Dutton et al;^Citation33 2014, USA	RCT	12 months	66	Behavioral intervention based on group sizes	Attendance: large group (n=31) – 49% Small group (n=35) – 62% Self-monitoring: large group (n=31) – 56.3% Small group (n=35) – 28.4%	6/10 pass	36.5	–	–
Greenberg et al;^Citation34 2009, Israel	RCT	24 months	322	Diet	Attendance – 84.5% Diet – 57%	7/10 pass	31.0	Higher adherence: low carbohydrate diet, postexercise Lower adherence: during holidays, current smoker, female sex, and less initial weight loss	–
Lemstra andRogers;^Citation35 2015, Canada	Pre/post	6 months	183	Exercise, diet, and CBT	Exercise – 81% Diet – 71% CBT – 68%	8/11 pass	37.7	Higher adherence: higher education and completion of a social support contract Lower adherence: past negative experiences with physical activity, high school or less than high school education, and depressed mood	Social support
McAndrew et al;^Citation36 2013, USA	RCT	3 months	69	Portion controlled weight loss intervention	Dietary adherence – 87%	8/10 pass	39.0	Higher adherence: self-monitoring of blood glucose	Social support
Meffert et al;^Citation37 2010, Germany	Pre/post	12 months	481	Metabolic balance nutrition program	Attendance – 61.6% Program adherence – 68%	6/11 pass	30.3	Lower adherence: noncompatibility with job, dissatisfaction with program, and personal counseling, individual nutrition plans	–
Shapiro et al;^Citation38 2012, USA	RCT	12 months	170	Self-monitoring via daily text messaging	Daily text – 60%	8/10 pass	32.2	–	Financial incentive
Steinberg et al;^Citation39 2013, USA	RCT	6 months	50	Self-monitoring via daily text messaging	Attendance – 90% Daily text (n=26) – 49%	9/10 pass	35.8	–	Financial incentive
Steinberg et al;^Citation40 2014, USA	RCT	12 months	194	Self-monitoring via IVR	IVR – 71.6%	6/10 pass	30.2	Higher adherence: older age and increasing education	–
Theim et al;^Citation41 2013, USA	RCT	5 months	101	FBT	Attendance: FBT – 85% MT – 75%	7/10 pass	35.1	–	Social support
Travier et al;^Citation42 2014, Spain	Pre/post	3 months	42	Diet and PA	Attendance: diet (n=37) – 92% PA (n=37) – 91%	7/11 pass	30.4	–	–
Turner-McGrievyet al;^Citation43 2007, USA	RCT	24 months	64	Diet	Vegan (n=31) – 61.3%, NCEP (n=31) – 54.8%	8/10 pass	–	–	Social support
Unick et al;^Citation44 2011, USA	RCT	12 months	2,503	Intensive lifestyle/diabetic support and education	Program adherence – 80%	6/10 pass	35.8	–	–
van Gool et al;^Citation45 2006, USA	RCT	18 month	238	Diet and PA	Attendance – diet (n=137) 52.3% Physical activity (n=133) 49.9%	6/10 pass	34.5	Higher adherence: Diet – low social participation and single status Exercise – exercising at home and no cardiovascular disease	–
Wang et al;^Citation46 2012, USA	RCT	12 months	210	Diet and PA self-monitoring	Paper record (n=72) – diet 34.4% and PA 29.7% PDA (n=68) – diet 57.8% and PA 59.4% PDA + feedback message (n=70) – diet 71.9% and PA 68.8%	6/10 pass	34.0	–	–

Abbreviations: CBT, Cognitive Behavioral Therapy; DASH, Dietary Approach to Stop Hypertension; ER, energy restriction; MMM, my meal mate; MR, meal replacement; MT, maintenance therapy; NCEP, National Cholesterol Education Program; PA, physical activity; PDA, personal digital assistant; RCT, randomized controlled trial; BMI, Body Mass Index; FBT, Family-Based Treatment; LEARN, Lifestyle, Exercise, Attitudes, Relationships, Nutrition; IVR, Interactive Voice Response.

Table 4 Adherence rate and rate ratio for multifactor subgroup analysis across baseline body mass index, study duration, incentive, social support, age, study design, and intervention type

Factor	Subgroup 1	N	Adherent (%)	Subgroup 2	N	Adherent (%)	Adherence rate ratio (1 vs 2)	95% CI
Baseline BMI	Overweight/moderate obesity	5,321	63.39	Severe/morbid obesity	4,598	61.56	1.03	1.00–1.06
Study duration	<12 months	2,771	69.88	≥12 months	7,591	53.01	1.32	1.28–1.36
Financial incentive	Financial incentive	538	61.79	No financial incentive	9,804	60.33	1.02	0.96–1.10
Social support	Social support	1,144	73.43	No social support	9,218	57.11	1.29	1.24–1.34
Age	Predicted by older age	469	60.97	Not predicted by older age	9,893	60.50	1.01	0.94–1.09
Study design	RCT	2,680	63.05	Pre/post	7,682	59.57	1.06	1.02–1.10
Intervention type	Supervised program	5,600	68.59	Diet	1,933	63.73	1.08	1.04–1.12
	PA	1,388	50.21	Self-monitoring	1,258	41.50	1.21	1.11–1.32
	Supervised program	5,600	68.59	Self-monitoring	1,258	41.50	1.65	1.54–1.77
	Diet	1,933	63.73	PA	1,388	50.21	1.27	1.19–1.35
	Supervised program	5,600	68.59	PA	1,388	50.21	1.37	1.29–1.44
	Diet	1,933	63.73	Self-monitoring	1,258	41.50	1.54	1.43–1.65

Notes: Potential moderators of exercise adherence were identified apriori and used as factors for a subgroup analysis. Subgroup 1 and 2 were used (for analytical purposes) to represent the sub-categories within each pre-determined factor. Adherence rates were estimated for each sub-category (subgroup) of the pre-determined factors. The adherence rates for each subgroup represents the pooled estimate for a particular sub-category of a given factor. Pairwise rate ratios were computed for all sub-categories of each factor. “Supervised program” and “Self-monitoring” as used above, refer to whether the participants were directly monitored by the investigators or not, respectively. Subgroup analysis by intervention type aims to determine which of supervised monitoring, self monitoring, diet alone, or physical activity alone had a greater effect on adherence to weight loss programs.

Abbreviations: N, number of participants in subgroup; PA, physical activity; RCT, randomized controlled trial; CI, confidence interval.

AcharyaSElciOSereikaSAdherence to a behavioral weight loss treatment program enhances weight loss and improvements in biomarkersPatient Prefer Adherence2009315116019936157

 PubMed Web of Science ®Google Scholar

AnnunziatoRTimkoCCrerandCA randomized trial examining differential meal replacement adherence in a weight loss maintenance program after one-year follow-upEat Behav200910317618319665101

 PubMed Web of Science ®Google Scholar

ArdJKumanyikaSStevensVEffect of group racial composition on weight loss in African AmericansObesity200816230631018239637

 PubMed Web of Science ®Google Scholar

AustinJSmithJGianiniLCampos-MeladyMAttitudinal familism predicts weight management adherence in Mexican American womenJ Behav Med201336325926922487966

 PubMed Web of Science ®Google Scholar

BartfieldJStevensVJeromeGBehavioral transitions and weight change patterns within the PREMIER TrialObesity20111981609161521455122

 PubMed Web of Science ®Google Scholar

BefortCNollenNEllerbeckESullivanDThomasJAhluwaliaJMotivational interviewing fails to improve outcomes of a behavioral weight loss program for obese African American women: a pilot randomized trialJ Behav Med200831536737718587639

 PubMed Web of Science ®Google Scholar

BurkeLStynMGlanzKSMART trial: a randomized clinical trial of self-monitoring in behavioral weight management-design and baseline findingsContemp Clin Trials200930654055119665588

 PubMed Web of Science ®Google Scholar

CarsonTEddingsKKrukowskiRLoveSHarvey-BerinoJWestDExamining social influence on participation and outcomes among a network of behavioral weight-loss intervention enrolleesJ Obes2013201318

 Google Scholar

CarterMBurleyVNykjaerCCadeJAdherence to a smart-phone application for weight loss compared to website and paper diary: pilot randomized controlled trialJ Med Internet Res2013154e3223587561

 PubMed Web of Science ®Google Scholar

ChurchTMartinCThompsonAEarnestCMikusCBlairSChanges in weight, waist circumference and compensatory responses with different doses of exercise among sedentary, overweight postmenopausal womenPLoS One200942e451519223984

 PubMed Web of Science ®Google Scholar

ColleyRHillsAO’Moore-SullivanTHickmanIPrinsJByrneNVariability in adherence to an unsupervised exercise prescription in obese womenInt J Obes Relat Metab Disord2008325837844

 Web of Science ®Google Scholar

DasSSaltzmanEGilhoolyCLow or moderate dietary energy restriction for long-term weight loss: what works best?Obesity200917112019202419390525

 PubMed Web of Science ®Google Scholar

DuttonGPhillipsJKukkamallaMCherringtonASaffordMPilot study evaluating the feasibility and initial outcomes of a primary care weight loss intervention with peer coachesDiabetes Educ201541336136825740817

 PubMed Web of Science ®Google Scholar

DuttonGNackersLDubyakPA randomized trial comparing weight loss treatment delivered in large versus small groupsInt J Behav Nutr Phys Act201411112325249056

 PubMed Web of Science ®Google Scholar

GreenbergIStampferMSchwarzfuchsDShaiIDIRECT GroupAdherence and success in long-term weight loss diets: the dietary intervention randomized controlled trial (DIRECT)J Am Coll Nutr200928215916819828901

 PubMed Web of Science ®Google Scholar

LemstraMRogersMThe importance of community consultation and social support in adhering to an obesity reduction program: results from the Healthy Weights InitiativePatient Preference and Adherence2015991473148026508843

 PubMed Web of Science ®Google Scholar

McAndrewLNapolitanoMPogachLThe impact of self-monitoring of blood glucose on a behavioral weight loss intervention for patients with Type 2 diabetesDiabetes Educ201239339740522735195

 PubMed Web of Science ®Google Scholar

MeffertCGerdesNProgram adherence and efectiveness of a commercial nutrition program: the metabolic balance studyJ Nutr Metab2010201018

 Google Scholar

ShapiroJKoroTDoranNText4Diet: a randomized controlled study using text messaging for weight loss behaviorsPrev Med201255541241722944150

 PubMed Web of Science ®Google Scholar

SteinbergDLevineEAskewSFoleyPBennettGDaily text messaging for weight control among racial and ethnic minority women: randomized controlled pilot studyJ Med Internet Res20131511e24424246427

 PubMed Web of Science ®Google Scholar

SteinbergDLevineELaneIAdherence to self-monitoring via interactive voice response technology in an ehealth intervention targeting weight gain prevention among Black women: randomized controlled trialJ Med Internet Res2014164e11424780934

 PubMed Web of Science ®Google Scholar

TheimKSintonMGoldschmidtAAdherence to behavioral targets and treatment attendance during a pediatric weight control trialObesity201321239439723532993

 PubMed Web of Science ®Google Scholar

TravierNFonseca-NunesAJavierreCEffect of a diet and physical activity intervention on body weight and nutritional patterns in overweight and obese breast cancer survivorsMed Oncol201431178324310809

 PubMed Web of Science ®Google Scholar

Turner-McGrievyGBarnardNScialliAA two-year randomized weight loss trial comparing a vegan diet to a more moderate low-fat dietObesity20071592276228117890496

 PubMed Web of Science ®Google Scholar

UnickJBeaversDJakicicJEffectiveness of lifestyle interventions for individuals with severe obesity and Type 2 diabetes: results from the Look AHEAD trialDiabetes Care201134102152215721836103

 PubMed Web of Science ®Google Scholar

van GoolCPenninxBKempenGDeterminants of high and low attendance to diet and exercise interventions among overweight and obese older adultsContemp Clin Trials200627322723716387555

 PubMed Web of Science ®Google Scholar

WangJSereikaSChasensEREwingLJMatthewsJTBurkeLEEffect of adherence to self-monitoring of diet and physical activity on weight loss in a technology-supported behavioral interventionPatient Prefer Adherence2012622122622536058

 PubMed Web of Science ®Google Scholar