High levels of readiness to change (RTC) are considered critical to the long-term success of weight management programs including bariatric surgery. However, there are no data to support this assertion. We hypothesize that RTC level will not influence weight outcomes following surgery. In 227 consecutive patients undergoing adjustable gastric banding surgery, we recorded reasons for seeking surgery, and RTC measured with the University of Rhode Island Change Assessment. Scores were blinded until study completion. The primary outcome measure was percentage of excess BMI loss at 2 years (%EBMIL-2); others included compliance and surgical complications. Of 227 subjects, 204 (90%) had weight measurement at 2 years. There was no significant correlation between RTC score and %EBMIL-2 (r = 0.047, P = 0.5). Using the median split for RTC score the lowest 102 subjects mean %EBMIL-2 was 52.9 ± 26.9% and the highest 52.2 ± 28.3%, P = 0.869. There was no weight loss difference between highest and lowest quartiles, or a nonlinear relationship between weight loss and RTC score. There was no significant relationship between RCT score and compliance, or likelihood of complications. Those motivated by appearance were more likely to be younger women who lost more weight at 2 years. Poor attendance at follow-up visits was associated with less weight loss, especially in men. Measures of RTC did not predict weight loss, compliance, or surgical complications. Caution is advised when using assessments of RTC to predict outcomes of bariatric surgery.
As the global obesity epidemic evolves, there has been a dramatic increase in those eligible for bariatric surgery. The number of US citizens with a BMI >50 increased by a factor of five times between 1986 and 2000 (ref. 1). During the past 10 years there has been a rapid increase in the utilization of weight loss surgery (2), and substantial evidence has emerged showing that it saves lives, improves or resolves comorbidity, and improves quality of life (3,4,5,6,7).
Some have considered bariatric surgery to be primarily behavioral therapy with outcomes highly dependent on careful assessment and selection of patients (8,9). However, predicting the successful patient based on preoperative clinical and psychological evaluation has been of limited value (10). The variation in weight outcomes, following bariatric surgery, is considerable but unfortunately cannot be substantially predicted using preoperative factors. There are also physiological factors relating to early satiation and prolonged satiety following a meal which reduce energy intake and lead to sustained changes in energy balance and weight loss (11,12). Just how gastrointestinal surgery produces a sustained change in energy balance is being slowly unraveled (13). We have shown, in a double-blind randomized crossover study, the remarkable change to hunger, satiation, and satiety that accompanies the removal of fluid from an adjustable gastric band (14).
High levels of motivation have been considered a critical necessity for behavioral weight loss programs. There is clear evidence that a behavioral component to conventional weight management programs improves outcome (15,16). However, there are limited data showing that motivation or, perhaps more relevant, readiness to change (RTC) has a major effect on weight outcomes. The limited prior research varies in the methods used to measure motivational constructs, and the results obtained are mixed. There is some evidence that indicates self-motivation, self-determination, RTC, and self-efficacy may play a small role in predicting short-term weight outcomes (17,18,19,20,21,22,23). An assessment of the specifically designed “Dieting Readiness Test” found it to be a poor predictor of weight loss and treatment attendance (24) and of little practical value (25). However, there is evidence that a greater level of motivation to lose weight or RTC is associated with better improvement in food selection and dietary composition (26,27).
We have previously shown that the weight loss following laparoscopic adjustable gastric banding (LAGB) surgery is not significantly associated with the patient's primary motivating factor that led them to seek surgery (28). On the other hand we have found that a range of nonpsychological factors are associated with poorer weight loss. These are increasing age, reduced physical ability, and greater insulin resistance (29). Physiological and technical factors rather than psychological factors have also been shown to be more predictive of weight loss outcomes (30).
High levels of motivation to lose weight have been thought to be important for success following bariatric surgery (31,32). However, there are no data that we could find to strongly support this assertion. The aim of this prospectively designed and conducted study was to explore this assertion.
The first task was to find a suitable objective measure of motivation. One commonly used model for assessing motivation is Prochaska's transtheoretical model of stages of change. These stages are precontemplation (PC), contemplation (C), action (A), and maintenance (M) (33). This model has been applied to a range of problem behaviors including substance abuse, gambling, dietary, weight management, and eating disorders (33,34,35,36). University of Rhode Island Change Assessment (URICA) Scale is the most widely studied measure of “the stages of change” and can be combined to measure readiness for change at entrance to an intervention or treatment program (37,38). The instrument is designed for a broad range of concerns and asks clients general questions about their “problem.” This instrument was chosen because of its generic nature, reliability, and psychometric properties as the most appropriate for the task (39,40).
In this study we investigate RTC and the patient's reason for seeking surgery prior to the intervention, and relate these to weight outcomes. We propose that the prime mechanism of action of adjustable gastric banding surgery is physiological and that the band is a tool causing sustained changes in hunger, satiation, and satiety. It is this physiological change that allows for changed eating behavior and weight loss. Therefore we hypothesize that patients' RTC will have little influence of weight outcomes. Our primary hypothesis is that the patient's level of RTC before the intervention will have no significant influence on weight loss at 2 years following band placement. There were several secondary analyses performed. These included an examination of RTC and reasons for seeking surgery with other secondary outcomes: surgical complications, poor weight loss, and poor compliance with follow-up. These secondary analyses were exploratory and the study was not powered for these multiple comparisons.
Methods and Procedures
The aim was to prospectively measure stages of change, RTC, and the reasons for seeking surgery in at least 220 consecutive patients who were undergoing primary LAGB surgery. Questionnaire results were stored in a database inaccessible to the multidisciplinary team looking after the patients.
The primary hypothesis was that there would not be a clinically significant positive relationship between higher preoperative motivation as measured by RTC and clinically significant better weight loss (measured as percentage of excess BMI loss (%EBMIL)) at 2 years after surgery.
Secondary research questions were as follows.
Is the level of presurgical RTC associated with compliance with follow-up attendances?
Is the level of presurgical RTC associated with the risk of surgical complications?
Are a patient's leading reasons for seeking surgery associated with variance of weight loss at 2 years?
Are there patterns of reasons for seeking surgery among those presenting for surgery? Could these influence weight outcomes?
Can reasons for seeking surgery predict those with poor weight loss at 2 years after surgery?
Weight loss measure
The primary outcome measure for the study was the patient's %EBMIL at 2 years (%EBMIL-2) following surgery. Excess BMI is the patients' BMI less 25. A BMI of 25 is the World Health Organization upper level of what is regarded normal. This is the recommended measure of the International Federation for the Surgery for Obesity (41). Weight was to be measured within a window period of ∼6–24 months for each patient, that is, at any time between 21 and 27 months following band placement. For those with multiple visits in this period the one closest to 24 months was selected. Also presented are patients' actual and percentage weight loss (see Table 2).
Table 2. The characteristics of the two groups based on their readiness to change (RTC) score low <80 and high 80+
Poor weight loss at >2 years after surgery was defined as a weight loss of <10%. Whilst 10% weight loss provides a significant level of health benefit, few achieve a sustained weight loss of >10% with nonsurgical weight loss methods. Ten percent weight loss is usually approximated as 25%EBMIL in most bariatric surgical cohorts.
All patients presented to a surgical weight loss program and were accepted for surgery. The patients recruited were to be the next 220 consecutive patients operated by P.E.O. to have a primary LAP-BAND System (Allergan Health, Irvine, CA) placement. The band was placed laparoscopically in all cases using the par-flaccida approach as described previously (42).
To be eligible for surgery patients required a BMI >30 kg/m2, significant obesity-related medical, physical, and/or psychosocial disabilities, and had failed several significant attempts to lose weight during a period of several years. Preoperative assessment included medical assessment, documentation of comorbidity, medication usage, anthropometric measurements, biochemical tests, and completion of standardized questionnaires. Patients were not excluded on the basis of psychological testing or clinical assessment of their motivation. Indeed all professionals assessing the patients try to be empathetic and nonjudgmental, with the background knowledge that these patients often experience discrimination and stigmatization from health-care professionals, service providers, and insurers (43). However, all patients were required to have a good understanding of the procedure and follow-up requirements and be able to give informed consent to having the procedure. The study was carried out in accordance with the Declaration of Helsinki and was approved by The Avenue Hospital ethics committee.
Two questionnaires were administered: a questionnaire seeking the motivation behind seeking surgery and URICA to measure RTC.
Statements regarding reason for seeking surgery. The first questionnaire sought the patient's major reason or motivation for seeking LAGB surgery. The questionnaire was a modification of the one we have previously published (28) (Table 1). Our previous research indicated that two items, one about appearance and one about embarrassment, were measuring the same idea/reason and were therefore combined into a single item. Two additional motivations for seeking surgery were also added as a result of the open-ended question “other” question at the end of the previous survey: seeking weight loss surgery to enhance employment prospects and being advised by a third party to seek a surgical opinion. Patients were asked to grade the statements from (1) the most important or appropriate statement to (7) the least important or appropriate statement.
Table 1. The questionnaire developed to assess the major reason or most appropriate statement related to a patient seeking laparoscopic adjustable gastric banding surgery (28)
URICA scale. The URICA is the most widely studied generic measure of readiness for change with higher scores indicating a greater RTC (44). The URICA can be used to assess a participant's RTC regarding a range of problems including, obesity, and diet and weight management. In our context we asked them to focus on their weight problem as their condition and the LAGB program which involves changes in eating behaviors, dietary intake, physical activity, and regular follow-up. At the time of completing the questionnaire they had attended a patient information seminar, read details about the program, and had consultations with the surgeon and specialist bariatric physician.
The URICA is a 32-item self-report measure that includes subscales measuring the Prochaska's transtheoretical model of stages of change: PC, C, A, and M. Responses are given on a 5-point Likert scale ranging from 1 (strong disagreement) to 5 (strong agreement). The subscales can be combined arithmetically (C + A + M − PC) to yield a second-order continuous RTC score that can be used to assess RTC at entrance to treatment (37,38). Reliability, construct validity, and psychometric assessment have been established for range behavioral conditions (39,40,45,46,47).
All responses were stored until all participants had completed at least 27 months following band placement. None of the multidisciplinary team looking after this group of patients had access to the participants' responses and did not know which patients were included within the study group.
Extensive baseline data are recorded regarding our bariatric surgical patients, therefore enabling the analysis has to be adjusted for confounding variables known to have an influence on weight outcomes such as initial BMI, age, sex, insulin resistance (using the homeostatic model assessment (48)), and physical ability (using the physical component summary score of the SF-36 (ref. 49)) (29).
Study power. The variables associated with the primary study outcome were continuous: URICA RTC score and %EBMIL-2. However, to date, there are no RTC score cutoff values that can be used to define outcomes. The current study will examine RTC scores in relation to %EBMIL-2 in several ways, as a continuous variable and looking at correlation, as a median split binary variable, and compared highest quartile to lowest quartile. In addition we would use an interpolation line to examine for any nonlinear trend.
To determine the minimum number of participants needed for this study we used the following conservative assumptions. If RTC scores influenced >5% of ultimate weight loss variance it may be clinically significant. In addition we estimated that a difference of 5% in the %EBMIL-2 between two groups after band placement would be the smallest difference that would be clinically relevant. Using our previous outcome data, mean, and s.d. of %EBMIL-2 following LAGB surgery, we calculated that 200 subjects were needed to complete the presurgery URICA RTC survey to have a power of 80% for detecting a significant difference (P < 0.05) of 5%EBMIL-2 between the 100 with the highest RTC scores and the 100 with the lowest scores. This number would also allow for the detection of <3% of weight outcome variance when assessed using correlation coefficients, and when controlled for confounding variables. It was planned to recruit at least 220 patients to allow for those who may be lost to follow-up, did not have a follow-up visit within the window period, had their band explanted or died during the 2-year period.
RTC scores and %EBMIL-2 were normally distributed as mean ± s.d. Raw correlations were assessed using Pearson correlation coefficients. Linear regression analysis was performed using forward and backward modeling to assess for any influence of RTC on %EBMIL when controlling for variables known to influence weight loss. The median split and upper and lower quartile groups, based on their RTC score, had mean %EBMIL compared using unpaired Student's t-test. ANOVA was used to test differences between more than two groups. Two-step cluster analysis was used to look for patterns of responses to the URICA scores and reasons for seeking surgery.
All analysis was performed using SPSS for Windows, version 14.0 (SPSS, Chicago, IL).
Two-hundred and twenty-seven consecutive patients completed the survey. All but two patients (both men) had weight recorded within the window at 1 year, and there were 23 at 2 years who did not have weight recorded. These 23 were more likely to be men (12 of 50, 26%) than women (11 of 177, 6.2%) P < 0.001. Of these 23 without 2-year weight recordings, 12 of 114 (52%) were in the high group using a median split for RTC prior to surgery, and 11 of 113 (48%) in the low group. They were more likely to have sought surgery to improve their health (P = 0.02).
The primary analysis therefore included 204 patients who had weight assessment at 2 years. The characteristics of the subjects included in the analysis are shown in Table 2. Both RTC score and %EBMIL-2 were normally distributed. There was no statistical correlation between these variables (r = 0.047, P = 0.5, R2 = 0.0022). Correlation between these variables gives us the greatest sensitivity that there is no correlation between RTC score and %EBMIL-2. Using a linear regression analysis and after controlling for age, BMI, gender, insulin resistance, and the PCS SF-36 score, the RTC score did not have an influence of the %EBMIL-2. The mean calculated RTC score was 80.7 ± 11.7 and ranged from 48 to 108. The median score was 79.5 and the high and low median split RTC score cutoff was <80 with 102 patients in each group. The 102 with the lowest scores for RCT achieved a mean %EBMI-2 of 52.9 ± 26.9% and those with the highest 52.2 ± 28.3%, unpaired t-test, P = 0.869. The difference between the groups was +0.7% with a 95% confidence interval of −7.0% and +8.3% for those with the lower than median RTC scores. Unusually large s.d. in %EBMI-2 do allow for the possibility for a >5% difference, either way, for the median split analysis. It is accepted that the analysis of continuous data is of greater power than dichotomous and given the lack of any positive trend in continuous data a clinical significant relationship is unlikely (50). The characteristics of these two groups along with confounding variables are shown in Table 2. There was no statistically significant difference in %EBMI-2 between the highest (51.1 ± 27.4%) and lowest quartiles (51.6 ± 27.4%), and the scatter plot of the continuous variables with interpolation line showed no visual evidence of a nonlinear trend. Thus our primary hypothesis is supported with the measurement of RTC having no significant influence of the weight outcomes at 2 years after band placement.
Stage of change clusters
Patients who had a 2-year weight assessment (n = 204) had their preoperative raw URICA for PC, C, A, and M scores examined for clustering characteristics using two-step cluster analysis. Three distinct groups or clusters emerged and based on their mean URICA raw score characteristics they were labeled with group tendencies (Figure 1). Names given were precontemplative, ready for change, and ambivalent. The characteristics of these three groups are shown in Table 3 and the only significant difference between the groups was their mean RTC scores. There were no differences in weight loss, follow-up attendance, or percentage with poor weight loss.
Table 3. Characteristics and outcomes based on the cluster analysis of the University of Rhode Island Change Assessment raw scores for those with a 2-year weight measure (n = 204)
Statement selection—reason or most appropriate statement
Of the 204 eligible participants, 191 (94%) assigned the number 1 to an individual statement. The leading statements in order of frequency were: to improve health (40%), to improve a medical condition (29%), to improve appearance (18%), to improve physical fitness (6%), to improve physical ability (5%), to improve employment prospects (1%), and on the advice of a third party (1%). Participants choosing appearance number 1 had higher %EBMIL-2 and higher RTC scores. They were significantly younger, and more likely to be women.
Patients' choices for each statement were graded in an ordinal way with 3 for choice 1 or 2, 2 for choice 3 or 4, and 1 for low preferences 5–7. The only ordinal choices that influenced %EBMIL-2 or RTC score were those for appearance. Ordinal scores of 3, 2, and 1 for the appearance question had mean %EBMIL-2 of 59.4, 50.3, and 47.1%, respectively (ANOVA, the difference between those scoring 3 and 1 were different, P = 0.019). This significant weight loss effect of choosing the appearance statement higher than others remained when controlled for significant covariates age and gender (ordinal logistic regression, P = 0.013). Ordinal scores of 3, 2, and 1 for appearance had a positive association with mean RTC scores of 83.4, 78.5, and 79.7%, respectively (ANOVA, the difference between those scoring 3 and 2 were different, P = 0.038). However, this association was not statistically significant after controlling for age and gender.
Cluster analysis revealed three patterns of responses to the ordinal scores for the seven statements. Cluster 1 (n = 64) was a mixed group that had a broad range of concerns, appearance, physical fitness, medical conditions, and concerns about employment or had been advised by others to seek surgery. Cluster 2 (n = 55) was motivated largely by appearance and physical fitness, and cluster 3 (n = 79) largely by medical conditions and concerns for health. Cluster 2 was younger, had better physical ability, better insulin sensitivity, and 95% were women. There were no statistical differences between groups for weight loss, poor weight loss, complication frequency, or poor follow-up when patients were examined in their statement selection clusters.
RTC—follow-up visits—weight loss
The mean number of follow-up visits in the 2 years after band placement was 19.6 ± 8.8 visits. There was no significant relationship between the RTC score and the compliance as indicated by the number of follow-up visits. There was a significant positive correlation between the number of visits and weight loss (r = +0.16, P = 0.02), but the relationship was not linear (Figure 2). The median was 18 and quartile cutoffs were 13, 18, and 24. The total cohort with weight measures at 2 years was divided into quartiles based on the number of visits during that period. Those with less than 13 visits had a significantly lower %EBMIL-2 than those with 13–24 follow-up visits. Men (16.6 ± 7.8 visits) overall tended to have fewer visits than women (19.4 ± 9.2, P = 0.06), and men who attended poorly (<13 visits in 2 years) had very poor %EBMIL (20.2 ± 12%) compared with women similarly attending <13 visits in 2 years (45.0 ± 32%, P = 0.007), as well as both men and women who attended more regularly (Figure 2). Poor attendance at follow-up and seeking surgery to improve appearance had opposite but independent effects on the weight loss outcome together providing 6% of the overall variance.
Poor weight loss
Thirty participants (14.7%) had poor weight loss defined as <10% weight loss at 2 years, and this identified the same 30 individuals with <25% of %EBMIL-2 loss. The participant's RTC score, URICA raw scores, and URICA cluster grouping were not associated with an increased risk of poor weight loss. However, those with poor weight loss were more likely to be in the high RTC score group (20 of 102) rather than the low (10 of 102), χ2P = 0.048. There was no association between the patient's main choices for seeking surgery and poor weight loss. There was a very strong relationship between poor weight loss and poor follow-up attendance (Figure 2). Of the 30 subjects with poor weight loss, 16 were in the lowest quartile of follow-up visits (P < 0.001). Poor follow-up attendance and high-motivation group were independent predictors of poor weight loss. The effect of poor attendance was most noticeable in men (Figure 2) and a total of 36% of men either did not have a 2 year weight recorded or had poor weight loss.
Band-related complications requiring surgical intervention within the 2-year period were recorded in 27 (13.2%) of those with 2-year weight recorded, 19 (9.3%) had revision for abnormal proximal gastric pouch enlargement either due to stomach prolapse through the band or symmetrical enlargement, and 9 (4.4%) had a system leak which needed the access port to be replaced. One sustained both complications. There were no erosions of the band into the stomach, leaks from the band itself, or permanent band explants. Those who had complications during the first 2 years of band placement had the same %EBMIL-2 of 52.7 ± 23.4% as those without 52.6 ± 28.2%. There were also no preoperative differences in RTC score, raw URICA scores, URICA motivation cluster grouping, or motivational statement cluster groupings, between those with and without a complication. The type of complication was not associated with any URICA scores or weight loss.
Our primary hypothesis that a preoperative score of a patient's level of RTC, using the generic URICA questionnaire, would not have a clinically significant influence on weight outcomes at 2 years after LAGB surgery has been supported. This finding is consistent with our hypothesis that the action of the band is physiological rather than largely behavioral, although we have not measured other weight-related behaviors such as diet, exercise, and social interactions during the postoperative period.
Our subjects, however, had all chosen surgical therapy and were therefore sufficiently motivated to take a major step in their quest to lose weight (51). On the other hand, the variance in weight outcomes are quite broad (Table 2) and one would expect that if preoperative motivation was relevant then it would explain some variance of the weight outcome. It is also of note that there is no clear evidence that compliance or weight outcomes are favorably affected by increased measures of motivation before nonsurgical weight loss interventions (19,20,22,24).
The assessment of pretreatment RTC may be problematic. There has been significant criticism of many measures of motivation based on the popular transtheoretical model, including the generic URICA questionnaire, and the current evidence suggests that it is of limited predictive value for substance abuse (44). The effect of a single pretreatment measure RTC is quite time dependent and, although it may have an effect on short-term behavior and compliance, it may be of limited long-term value. In addition an assessment that can predict short-term behavioral outcomes may be of very limited value is predicting the management outcomes of chronic relapsing conditions such as substance abuse and severe obesity. These criticisms apply to our currently used measures and one must be cautious about applying any presurgical assessment of motivation as a predictor of bariatric surgical outcomes. Patients who present themselves for bariatric surgery accept their problem and want to address it. Making a temporal judgment about their level of motivation or RTC and their likelihood of success may be problematic, and to exclude a patient from surgery based on such a judgment may be discriminatory. Severely obese patients often experience unreasonable barriers when seeking effective therapy.
Sustained weight loss is difficult to achieve and there is good evidence that there are powerful central nervous system mechanisms to defend energy balance and regain lost weight (52,53). The ability to lose weight is extremely variable and is a complex interaction of environmental, behavioral, and polygenic factors (54). Surgery, for those who have failed to lose through less invasive means of weight loss, adds a new layer of complexity with a gastrointestinal intervention influencing energy balance through many potential neuroendocrine targets involved at some level in the gut-brain axis (55). Some targets potentially influenced by surgery will also have polygenic variability that in turn can influence behaviors, energy balance, and the weight outcomes of bariatric surgery.
This study has found that concern about appearance preoperatively is associated with better weight outcomes after controlling for age and sex. This is interesting as in weight management programs the emphasis is often more focused on health and fitness, rather than improved appearance. Improving appearance is seen by many as a less worthy reason for seeking help, especially surgery. Clinicians may help their patients by being sensitive and discussing both health and appearance concerns (56) and certainly not dismissing an interest in improved appearance as less worthy. Appearance and health concerns have been found to be the major motivating factors in successful dieters (57). We have previously demonstrated high levels of symptoms of depression in LAGB candidates motivated by concerns with appearance (28) and major improvement in the symptoms of depression with LAGB induced weight loss, especially in young women with poor body image (58).
This study highlights the association between regular follow-up and better weight loss. We and others have reported the association (59), but the strength of the association in men appears to be very strong. Men were overrepresented in those without a 2-year weight measure and excluded from the analysis. Taken together these findings suggest that specifically targeting men early when they fail to attend follow-up visits may reduce the risk of unacceptable weight loss. Of course associations do not imply causality and men who are doing poorly may be less likely to attend. An alternative hypothesis is that men are more often given the larger form of the LAGB system and this can take more adjustments to achieve a satisfactory fill volume or satiety, therefore those that attend less frequently may be less likely to have an active fill volume.
In conclusion, we have not found that the level of a patient's motivation, as measured by the URICA RTC score, is associated with an effect on weight loss 2 years after LAGB surgery. We would advise to be cautious in using any preoperative assessment of level of motivation as an indicator of likely success for LAGB surgery.