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Summary

  1. Top of page
  2. Summary
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Acknowledgments
  8. Author contributions
  9. References

Aims

This study compared health-related quality of life (HRQOL) in adults with type 2 diabetes mellitus (T2DM) who reported their perception of weight change vs. actual weight change.

Methods

Respondents to the US Study to Help Improve Early evaluation and management of risk factors Leading to Diabetes (SHIELD) 2008 survey were asked if they had lost, maintained or gained weight compared with 1 year earlier (perception). Respondents also provided their actual weight and completed the SHIELD WQ-9 questionnaire to report how weight change affected 9 aspects of daily life. Perceived weight loss or gain was compared with measured weight change reported (2007 weight – 2008 weight) in those with T2DM.

Results

In respondents reporting weight loss (= 762), 75.4% lost weight and 15.9% gained weight. For respondents reporting weight gain (= 392), 70.2% gained weight and 19.6% lost weight. HRQOL did not differ between those who reported weight loss and actually lost weight vs. those who reported weight loss and actually gained weight (p > 0.05), except for self-esteem (p = 0.004). HRQOL was similar for those who reported weight gain and actually gained weight vs. those who reported weight gain, but actually lost weight (p > 0.20). Respondents who had perceived weight loss had significantly better HRQOL than those who perceived that they had gained weight.

Conclusions

Perception of weight loss/gain may be as powerful as actual weight loss/gain in impacting HRQOL among adults with T2DM. Interventions that help individuals lose weight or perceive weight loss in addition to lowering glucose will assist in improving HRQOL.

What's known

  • There has been a dramatic increase in diabetes and obesity worldwide during the last decade. Weight loss is associated with improvements in glycaemic control among adults with type 2 diabetes mellitus. Weight loss is associated with improvements in health-related quality of life among individuals who are overweight or obese.

What's new

  • This study provides evidence that self-perception of weight change impacts health-related quality of life in the same manner as actual weight loss or weight gain among adults with type 2 diabetes mellitus. Additionally, this study adds to the scarce data available for type 2 diabetes mellitus and the impact of weight change on quality of life among these individuals.

Introduction

  1. Top of page
  2. Summary
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Acknowledgments
  8. Author contributions
  9. References

There is evidence that weight loss is associated with improvement in health-related quality of life (HRQOL), typically in physical functioning and bodily pain, among adults who were overweight or obese participating in weight loss interventions [1-4]. Likewise, studies examining change in weight over time have shown that weight gain led to a reduction in HRQOL [1, 5]. However, scant information is available indicating if the association between weight change and HRQOL occurs in individuals with type 2 diabetes mellitus (T2DM). A clinical trial of obese patients with T2DM showed that patients who lost > 5% of body weight using sibutramine had improved HRQOL [6]. A large, real-world observational study of individuals with T2DM showed that self-reported weight loss was associated with improved well-being [7].

With the alarming rates of diabetes and obesity worldwide [8-10], it is important to understand whether self-perception of weight change influences HRQOL in the same manner as actual weight change. The number of people with T2DM is increasing in every country, with over 366 million people with diabetes in 2011 [9]. More than 1.1 billion adults worldwide were overweight, and 312 million were obese as reported in 2007 [10]. Weight loss has been shown to reduce insulin resistance and improve glycaemic control [11, 12]. Thus, weight loss may improve health outcomes for adults with T2DM, especially among the 85% of T2DM patients who are overweight or obese [13].

It is unknown whether the benefit of weight loss on improved HRQOL, and conversely, the detriment of weight gain on HRQOL, is because of actual change in body weight or to the individual's perception of the weight change, or perhaps both. Individuals may feel better if they perceive that they have lost weight, especially if they have been making a concerted effort to lose weight. Actual weight loss may not have occurred or it may have been the loss of 1–2 pounds, which may or may not have had an impact on HRQOL. The improved HRQOL with perceived weight loss may consequently assist T2DM patients with medication adherence and satisfaction with their diabetes treatment such that patients receive fuller benefit from their therapy, which, in turn, improves glycaemic control and leads to better health outcomes. The same pathway may be true for weight gain, with individuals feeling poorly if they perceived that they had gained weight, regardless of the actual weight change. The reduced HRQOL may lead to poor medication adherence and dissatisfaction with their diabetes therapy and, ultimately, poor glycaemic control. Thus, it is important to determine if self-perception of weight change, regardless of actual weight change, impacts HRQOL among individuals with T2DM. The objective of this study was to compare HRQOL in adults with T2DM who reported their perception of weight change vs. their actual weight change.

Methods

  1. Top of page
  2. Summary
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Acknowledgments
  8. Author contributions
  9. References

The present investigation is an analysis of data from the Study to Help Improve Early evaluation and management of risk factors Leading to Diabetes (SHIELD) assessing the association between HRQOL and self-perception of weight change stratified by actual weight change. SHIELD is a 5-year, survey-based study conducted to better understand patterns of health status, health behaviour, and quality of life of people living with diabetes and those with varying levels of cardiometabolic risk.

SHIELD survey

SHIELD included an initial screening phase to identify cases of interest in the general adult population (e.g., diabetes mellitus), a baseline survey to follow up identified cases with a questionnaire about health status, health knowledge and attitudes, and current behaviours and treatments and annual follow-up surveys. A detailed description of the SHIELD methodology has been published previously [14, 15].

In brief, the screening survey was mailed in April 2004 to a stratified random sample of 200,000 US households, representative of the US population for geographical residence, household size and income, and age of head of household [16], identified by the Taylor Nelson Sofres National Family Opinion (TNS NFO) panel (Greenwich, CT). All TNS NFO surveys were voluntary, and no special incentives were provided. A response rate of 64% (128,000 households with data on 211,097 individuals) was obtained for the screening survey. The SHIELD study was approved by the Quorum Review Board.

A comprehensive baseline survey was mailed in September–October 2004 to a representative sample of adults (= 22,001) who were identified in the screening survey as having self-reported type 1 diabetes mellitus or T2DM, no diabetes, or being at risk for diabetes. Each respondent group was balanced to be representative of that segment of the population for age, gender, geographical region, household size and income for the US population, and then a random sample from each group was selected and sent the baseline survey. A response rate of 72% was obtained for the baseline survey. The 2008 annual follow-up survey (response rate of 71%) included the SHIELD-WQ-9 questionnaire on weight change and how the weight change affected nine aspects of daily life. Responses from the 2008 survey and body weight from the 2007 survey were analysed and reported in this study.

Study measures

Respondents were classified as having T2DM based on their self-report of having been told by a doctor, nurse, or other healthcare professional that they had T2DM. Other cardiovascular comorbid conditions were identified in a similar manner, with respondents having been told by a healthcare professional that they had cholesterol problems, heart disease/heart attack, hypertension, or narrow or blocked arteries.

For perceived weight change, respondents were asked to compare their current weight with their weight 1 year earlier and to indicate if they had gained weight, lost weight, stayed the same, lost weight then gained it back, or gained weight but lost it again. Weight and height were self-reported at the time of the 2007 and 2008 surveys. Actual weight change was computed by subtracting weight as reported in the 2007 survey from weight reported in the 2008 survey. Body mass index (BMI) was determined using the actual weight and height; overweight was defined as BMI of 25.0–29.9 kg/m2, and obese was defined as BMI ≥ 30 kg/m2.

Utilising the SHIELD-WQ-9, a questionnaire developed to focus the HRQOL assessment on weight change, respondents were asked the following: ‘Thinking about your weight change or lack of weight change over the past year, how did this change (or lack of change) affect you in the following areas? In the past year, my change or lack of change in weight had the following effects.’ Response categories were ‘worsened, improved, stayed the same and not applicable.’ The 9 following areas were reported: (i) how I feel physically – physical health, (ii) my interactions with family, (iii) my work performance, (iv) my interactions with co-workers and friends, (v) my social activities, (vi) my daily activities, (vii) my self-esteem, (viii) how I feel emotionally – emotional health, and (ix) my overall quality of life. The SHIELD-WQ-9 was developed to assess HRQOL specific to changes in weight using the same domains (e.g. physical health, mental health), similar to other HRQOL instruments such as the SF-36 and SF-12. Findings from the SHIELD-WQ-9 have been reported in a previous study [7].

Statistical analysis

The proportion of respondents reporting weight loss or weight gain (perception) over the past year was computed for respondents with T2DM. Respondents who reported no change (stayed the same) in weight or fluctuating weight were excluded from the analysis, as the impact on HRQOL was expected to be negligible. Comparisons between T2DM respondents who reported losing weight and those who reported gaining weight were made using chi-square tests for categorical variables and t-tests for continuous variables. A subgroup analysis was conducted to assess the impact of overweight/obesity on the association of weight change and HRQOL. The weight change groups were stratified by overweight/obese vs. normal weight and the proportion reporting improvement in HRQOL was compared within the perceived weight loss groups. Statistical significance was set a priori as p < 0.05.

Results

  1. Top of page
  2. Summary
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Acknowledgments
  8. Author contributions
  9. References

From the 2008 survey, 895 T2DM respondents reported (perceived) losing weight and 460 T2DM respondents reported gaining weight over the past year. T2DM respondents who perceived weight loss were older, by 3 years on average, and weighed less (by 21 pounds on average) at the time of the 2008 survey than T2DM respondents who perceived weight gain (p < 0.05) (Table 1). A greater proportion of T2DM respondents who perceived weight gain were obese, compared with respondents who perceived weight loss (77% vs. 63%, p < 0.001). Respondents who perceived weight loss were similar to respondents who reported weight gain with regard to gender, race, household income, education and cardiovascular comorbid conditions (p > 0.10). T2DM respondents who perceived weight loss actually lost an average of 9.2 pounds, with 42% of respondents actually losing 10 or more pounds and 5.2% actually gaining 10 or more pounds. T2DM respondents who perceived weight gain actually had a mean increase of 7.1 pounds, with 37.5% of respondents actually gaining 10 or more pounds and 8.5% actually losing 10 or more pounds.

Table 1. Characteristics of respondents with type 2 diabetes mellitus who perceived losing or gaining weight in the past year (= 1355)
CharacteristicsPerceived weight loss (= 895)Perceived weight gain (= 460)
  1. a

    p < 0.05 for comparison of perceived weight loss vs. perceived weight gain.

  2. b

    Statistically significant difference in BMI category between weight change groups; 1 pound (lb) = 0.4536 kg.

Age, years, mean (SD)63.0 (11.8)a60.0 (10.6)
Women,%61.163.9
White,%74.670.7
Education, high school degree or less,%31.736.4
Household income, < $35,000,%34.936.1
Cholesterol problems, %73.576.7
Heart disease/heart attack, %26.323.7
Hypertension, %73.076.7
Narrow or blocked arteries, %10.37.6
Weight, lbs, mean (SD)209.7 (54.7)a230.9 (60.8)
Body mass index (BMI) category, %ab
Normal weight (BMI < 25.0 kg/m2)11.83.8
Overweight (BMI = 25.0–29.9 kg/m2)25.619.6
Obese (BMI ≥ 30.0 kg/m2)62.676.7
Actual weight change from 2007 to 2008, lb
Mean (SD)−9.2 (17.0)a7.1 (16.7)
Category of weight loss,%
≥ 2018.34.5
15–198.31.5
10–1415.42.5
5–921.25.5
1–412.26.3
0, weight neutral8.810.3
Category of weight gain ,%
1–44.611.8
5–95.920.3
10–141.512.0
15–190.86.5
≥ 202.919.0

Perceived vs. actual weight change

Of the 1355 eligible T2DM respondents, 1180 (87%) completed the SHIELD-WQ-9 questionnaire. Of the 1,180 respondents, 66.1% perceived weight loss and 33.9% perceived weight gain. For T2DM respondents who perceived weight loss, 75.4% had actual weight loss, 15.8% had actual weight gain and 8.8% had no change in actual weight (Figure 1). For T2DM respondents who perceived weight gain, 69.5% had actual weight gain, 20.3% had actual weight loss and 10.2% had no change in actual weight (Figure 1). The correlation between perceived and actual weight change was r = 0.56.

image

Figure 1. Percentage of T2DM respondents who perceived weight loss or weight gain by actual weight change

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Health-related quality of life and weight change

The proportion of T2DM respondents who reported improvement for each of the SHIELD-WQ-9 questions was stratified by perceived and actual weight change (Table 2). The proportion of respondents reporting improvement in the 9 HRQOL domains was similar between respondents who perceived weight loss and actually lost weight vs. respondents who perceived weight loss but actually gained weight (p > 0.05), except for self-esteem (p = 0.004). For example, 48.5% of T2DM respondents who perceived weight loss and actually lost weight reported improvement in physical health compared with 38.8% of T2DM respondents who perceived weight loss, but actually gained weight (p > 0.05). The proportion of respondents reporting improvement in the 9 HRQOL domains was also similar between respondents who perceived weight gain and actually gained weight vs. respondents who perceived weight gain, but actually lost weight (p > 0.25) (Table 2). Between 3% and 8% of T2DM respondents perceiving weight gain reported improvement in HRQOL.

Table 2. Proportion of T2DM respondents who reported improvement in health-related quality of life by perceived weight change and actual weight change
SHIELD-WQ-9, Respondents indicating improvement over the past year (%)Perceived weight loss (= 780)bPerceived weight gain (= 400)c
Perceived weight loss and actually lost weight (= 588)Perceived weight loss and actually gained weight (= 123)Perceived weight gain and actually gained weight (= 278)Perceived weight gain and actually lost weight (= 81)
  1. a

    p = 0.004 for comparison of perceived weight loss and actual weight loss vs. perceived weight loss but actual weight gain.

    69 respondents stayed the same weight.

    41 respondents stayed the same weight.

  2. b

    69 respondents stayed the same weight.

  3. c

    41 respondents stayed the same weight.

Physical health48.538.83.31.3
Interactions with family20.516.56.15.5
Work performance25.521.52.93.7
Interactions with co-workers/friends16.613.62.96.1
Social activities18.918.32.84.2
Daily activities26.423.34.62.7
Self-esteem43.2a29.24.68.0
Emotional health34.327.04.68.0
Overall quality of life36.230.34.56.8

Among T2DM respondents who perceived weight loss and actually lost weight, significantly more reported improvement in all nine domains of HRQOL than T2DM respondents who perceived weight gain and actually gained weight (p < 0.0001) (Table 2). For example, 36.2% of respondents who perceived weight loss and actually lost weight reported improvement in overall quality of life compared with 4.5% of respondents who perceived weight gain and actually gained weight (p < 0.0001). Similarly, significantly more T2DM respondents who perceived weight loss and actually lost weight reported improvement in all nine domains of HRQOL (14–39%) than T2DM respondents who perceived weight gain, but actually lost weight (1–8%, p < 0.001), except for interactions with co-workers/friends (p = 0.054).

Subgroup analysis: obesity impact

Assessing whether overweight/obesity modulated the effect of perceived weight change on HRQOL, a significantly greater proportion of overweight/obese respondents reported improvement in seven of the nine HRQOL domains compared with normal weight respondents among those who perceived weight loss and actually lost weight (Table 3). There was no significant difference in the proportion reporting improvement in HRQOL domains between overweight/obese and normal weight respondents who perceived weight loss and actually gained weight. In comparing overweight/obese respondents who perceived weight loss and actually lost weight vs. overweight/obese respondents who perceived weight loss and actually gained weight, a greater proportion reporting improvement in physical health (p = 0.025) and self-esteem (p = 0.002) was observed for those respondents with actual weight loss. The proportion reporting improvement was similar for the other seven domains (p > 0.05 for comparison between overweight/obese respondents who perceived weight loss and actually lost weight vs. actually gained weight), similar to the pattern observed for all respondents regardless of obesity stratification.

Table 3. Proportion of T2DM respondents with perceived weight loss who reported improvement in health-related quality of life stratified by obesity
SHIELD-WQ-9, respondents indicating improvement over the past year (%)Perceived weight loss and actually lost weightPerceived weight loss and actually gained weight
Normal weight (= 82)Overweight or obese (= 490)Normal weight (= 7)Overweight or obese (= 113)
  1. a

    p < 0.05 for comparison of normal weight vs. overweight or obese; statistically significant difference for comparison of overweight/obese respondents who perceived weight loss and actual weight loss vs. perceived weight loss and actual weight gain observed only for physical health and self-esteem.

Physical health25.652.0a14.339.8
Interactions with family12.022.1a25.015.9
Work performance16.727.116.721.8
Interactions with co-workers/friends10.817.728.612.5
Social activities9.220.6a14.318.6
Daily activities10.029.3a024.3
Self-esteem25.646.4a12.529.7
Emotional health16.337.3a14.327.1
Overall quality of life21.338.6a031.9

There were too few respondents who reported HRQOL improvement among the respondents who perceived weight gain (= 10) to assess the impact of overweight/obesity on the association between perceived weight gain and HRQOL.

Discussion

  1. Top of page
  2. Summary
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Acknowledgments
  8. Author contributions
  9. References

The majority of T2DM respondents who perceived weight loss actually lost weight (75%), and the majority of T2DM respondents who perceived weight gain actually gained weight (70%). Yet, some respondents who perceived weight loss actually gained weight (16%), and some respondents who perceived weight gain actually lost weight (20%). However, HRQOL did not differ by actual weight change for T2DM respondents who perceived weight loss or for T2DM respondents who perceived weight gain. This evidence indicates that perception of weight loss/gain may be as impactful on HRQOL as actual weight loss/gain. This association was not modulated by overweight/obesity and, in fact, a greater proportion of overweight/obese respondents reported improvement in HRQOL than normal weight respondents for those who perceived weight loss and actually lost weight.

Improved HRQOL with perceived weight loss may lead to better medication adherence and satisfaction with diabetes treatment such that T2DM patients may take their diabetes medications as recommended and gain greater benefit from the therapy. With better medication adherence, T2DM patients may improve their glycaemic control and avoid or reduce their risk of diabetes complications such as neuropathy, nephropathy, and cardiovascular disease. Further research is needed to test the hypothesis that improved HRQOL with perceived weight loss positively impacts medication adherence among T2DM patients.

T2DM respondents who perceived weight loss regardless of actual weight loss or gain had significantly better HRQOL than T2DM respondents who perceived weight gain regardless of actual weight gain or loss. A previous report of the SHIELD T2DM cohort had similar results to the present study, finding that self-reported (perceived) weight loss was associated with improved HRQOL and better exercise and weight management behaviours among adults with T2DM [7]. The cohort of T2DM respondents used in the previous SHIELD investigation was used in the present study with the purpose of investigating the association between perceived and actual weight change. It is important to note that the association with perceived weight change also applied to exercise and weight management behaviours among the T2DM respondents. More respondents who perceived weight loss reported exercising regularly, were rated as highly active by the International Physical Activity Questionnaire, and reported diet improvements such as limiting calories and eating less fat and more fibre compared with respondents who perceived weight gain [7].

Studies assessing the effects of weight loss interventions, including diet and behaviour modification and weight loss drugs, showed that actual weight loss was associated with improvement in HRQOL [1-4]. Standardised measurement of weight was not possible in the SHIELD study because it was a mailed survey to over 20,000 adults across the United States. However, the same association with HRQOL was demonstrated with perceived (self-reported) weight change.

The HRQOL evaluation in this study was performed using the SHIELD-WQ-9, a new weight-related questionnaire. The SHIELD-WQ-9 was developed specifically to elicit HRQOL based on changes in weight rather than other health-related events that occur in the same time period (past year) [7]. Generic HRQOL surveys like the SF-36, SF-12, and EQ-5D are not targeted to the impact of weight change, but evaluate overall HRQOL based on all aspects of life that occur in the recall period, including diabetes and other health conditions.

The present study used a large, population-based sample of T2DM respondents to assess perceived and actual weight change and the impact on HRQOL. There are limitations to the study that should be considered. Information about glycaemic control [glycated haemoglobin (HbA1c) levels] was not collected in the SHIELD survey, so the impact of improved HRQOL with perceived weight loss on glycaemic control could not be investigated. The determination of T2DM and weight was made based upon self-report rather than clinical or laboratory measures. However, this determination was made consistently for all respondent groups evaluated in this study, so it should not have affected the comparison across groups. Furthermore, previous studies demonstrated that self-reported weight and height are accurate and reliable [17, 18]. Household panels, like the SHIELD study, tend to underrepresent the very wealthy and very poor segments of the population and do not include military or institutionalised individuals. These limitations are true for most random sampling and clinically based methodologies. Self-selection bias may be present because respondents were those who could read and comprehend the survey.

In conclusion, perception of weight loss or weight gain may be as impactful on HRQOL as actual weight loss or weight gain among adults with T2DM. T2DM respondents who perceived weight loss, regardless of actual weight loss or gain, had significantly better HRQOL than T2DM respondents who perceived weight gain, regardless of actual weight gain or loss. Interventions that help adults lose weight or perceive weight loss in addition to lowering glucose may assist in optimising diabetes disease management and improving HRQOL.

Acknowledgments

  1. Top of page
  2. Summary
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Acknowledgments
  8. Author contributions
  9. References

Members of the SHIELD Study Group are: Harold Bays, MD, Louisville Metabolic and Atherosclerosis Research Center, Louisville, KY; Debbra D. Bazata, RD, CDE, St. Luke's Primary Care South, Overland Park, KS; James R. Gavin III, MD, PhD, Emory University School of Medicine, Atlanta, GA; Andrew J. Green, MD, Midwestern Endocrinology, Overland Park, KS; Sandra J. Lewis, MD, Northwest Cardiovascular Institute, Portland, OR; Michael L. Reed, PhD, Vedanta Research, Chapel Hill, NC; and Helena W. Rodbard, MD, Endocrine and Metabolic Associates, Rockville, MD. Tina Fanning of Vedanta Research, Chapel Hill, NC, also contributed to this report, performing data collection and analysis. This research was funded by AstraZeneca LP. The funder did not have a role in study design, data collection, data analysis, manuscript preparation or publication decisions, except through author Susan Grandy, PhD, who is an employee of AstraZeneca LP.

Author contributions

  1. Top of page
  2. Summary
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Acknowledgments
  8. Author contributions
  9. References

SG substantially contributed to the study concept and design, interpretation of the data, contributed to the discussion and reviewed and edited the manuscript. KMF substantially contributed to the data analysis, interpretation of the data, contributed to the discussion and wrote the manuscript. DDB substantially contributed to the study concept and design, contributed to the discussion, and reviewed and edited the manuscript.

This research was presented at the 2011 World Diabetes Congress, Dubai, United Arab Emirates, December 4–8, 2011.

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  6. Discussion
  7. Acknowledgments
  8. Author contributions
  9. References
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