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Keywords:

  • antiobesity agents;
  • epidemiology;
  • Canada;
  • orlistat;
  • sibutramine

Abstract

  1. Top of page
  2. Abstract
  3. Introduction
  4. Research Methods and Procedures
  5. Results
  6. Discussion
  7. Acknowledgement
  8. References

Objective: Obesity and overweight are affecting increasing numbers of Canadians and have received considerable amounts of medical, governmental, and media attention in recent years. This study sought to determine whether this rise in prevalence and awareness has resulted in an increased frequency of obesity and overweight-related office visits or antiobesity drug prescriptions over the past 5 years.

Research Methods and Procedures: Data from IMS Health Canada were used to derive nationally representative estimates of trends in the annual number of obesity and overweight-related office visits (1999 to 2003) and the quarterly prescription volume of antiobesity drugs (July 1998 to March 2003) in Canada.

Results: The number of obesity and overweight-related office visits increased by 20% between 1999 and 2000 but then remained constant. The number of antiobesity drug prescriptions peaked in 2001 and has since declined, with parallel trends being observed for all individual agents. In contrast, the overall frequency of office visits and drug prescriptions in Canada (for any reason) progressively increased over the study period. Middle-aged women were the most common type of patient to seek physician advice regarding obesity, and general practitioners were the most common type of physician visited.

Discussion: Increases in the prevalence and awareness of obesity have not resulted in major increases in office visits or drug prescriptions for this condition over the past 5 years. A number of patient, physician, and drug-related factors may explain these results, which are likely a reflection primarily of the current lack of effective weight loss strategies for obese individuals.


Introduction

  1. Top of page
  2. Abstract
  3. Introduction
  4. Research Methods and Procedures
  5. Results
  6. Discussion
  7. Acknowledgement
  8. References

Obesity and overweight are globally epidemic and affect an estimated 1 billion adults worldwide (1). Prevalence rates in Canada have risen steadily over the past 3 decades (2, 3), and conservative estimates suggest that nearly one-half of adult Canadians are obese or overweight (4). In the United States, nearly one-third of individuals are obese, and two-thirds are overweight (5). Obese individuals experience significant morbidity due to chronic illness (6), premature mortality (7), and diminished quality of life (8) and consume a disproportionately greater share of health care resources compared with individuals with normal body weight (9, 10, 11).

The dramatic rise in the prevalence of obesity has received considerable attention within the media, government, and medical profession. Clinical guidelines and editorials in major journals have emphasized the need to recognize obesity as a serious, chronic medical illness and develop effective long-term individual and societal strategies for its prevention and treatment (12, 13, 14, 15, 16, 17). The importance of regular, frequent follow-up in promoting weight loss has been emphasized (14). Physicians play a central role in the identification and management of obesity and related complications. Patients who receive weight loss encouragement are nearly 3 times more likely to attempt weight loss; yet, fewer than 50% of obese individuals are advised by their physicians to lose weight (18).

With the rise in obesity prevalence, there has also been a renewed interest in pharmacological therapies for obesity. Current guidelines recommend considering drug therapy for individuals with a BMI of 30 kg/m2 or greater or a BMI of 27 kg/m2 or greater in the presence of obesity-related comorbidity (19). The two agents recently approved for long-term use, orlistat and sibutramine, result in average weight losses of 3% to 5% of initial body weight in placebo-controlled trials (20).

This study sought to determine whether obesity and overweight-related office visits and drug prescriptions in Canada have increased in conjunction with the increase in obesity prevalence rates, increased media coverage for obesity and related complications, and the promulgation of literature suggesting that a greater emphasis be placed on the chronic management and follow-up of obese individuals.

Research Methods and Procedures

  1. Top of page
  2. Abstract
  3. Introduction
  4. Research Methods and Procedures
  5. Results
  6. Discussion
  7. Acknowledgement
  8. References

Data for this study were provided by IMS Health Canada, which surveys office-based physicians and retail pharmacies across the nation. All analyses and interpretation of the data were performed independently of IMS Health Canada.

The Canadian Disease and Therapeutics Index (CDTI)1 and the CompuScript database were the two major databases used. The CDTI is comprised of data from 652 physicians of various specialties who are chosen by random sampling, stratified by geographic region. Each quarter, two consecutive workdays are randomly selected, and details of each patient visit are recorded, including information on patient demographics, primary and comorbid diagnoses, and medications. Anthropometric data are not routinely recorded. Each diagnosis and treatment plan addressed during the visit is recorded as a separate entry. Physicians are compensated for their participation and accuracy. Internal validity is verified through random sampling; however, external validity is limited by a large yearly physician drop-out rate (45%).

The IMS Health CompuScript database estimates the number of prescriptions dispensed by over 4700 Canadian pharmacies, representing two-thirds of retail pharmacies across the nation. Information is collected on a monthly basis and includes prescription volumes, dose frequency, drug cost, and patient demographics.

Data from the CDTI database were used to derive nationally representative, weighted estimates of the number of annual physician visits for obesity in adult patients (age > 20 years) from 1999 to 2003. The 95% confidence intervals (CIs) for these annual point estimates are ±19% in relative terms. Data from the CompuScript database were used to derive similar estimates of the quarterly frequency of prescription volumes for antiobesity agents from July 1998 to March 2004.

Results

  1. Top of page
  2. Abstract
  3. Introduction
  4. Research Methods and Procedures
  5. Results
  6. Discussion
  7. Acknowledgement
  8. References

Office Visits to Canadian Physicians for Obesity

The annual frequency of office visits for obesity or overweight increased by ∼20% between 1999 and 2000, but remained relatively constant thereafter (Figure 1). In contrast, the overall number of office visits to Canadian physicians (for any reason) trended upwards from 2000 to 2004.

image

Figure 1. Annual office visits to Canadian physicians (1999 to 2003). Error bars indicate 95% CIs (±19% of point estimate).

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In 2003, middle-aged females comprised the group that most commonly visited a physician for excess body weight (Figure 2). The proportion of patients within a given age and gender category was virtually identical across survey years (data not shown). Seventy-nine percent of visits were to general practitioners, 11% to general surgeons, 4% to internists, 3% to pediatricians, and the remainder to other specialties.

image

Figure 2. Age and gender of patients visiting physicians for obesity in 2003.

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Prescribing Patterns of Antiobesity Medications in Canada

There was a dramatic rise in the quarterly prescription volumes for antiobesity medications after May 1999, coinciding with the release of orlistat (Figure 3). Orlistat prescription volumes peaked in early 2000, and total antiobesity drug use peaked in 2001. Prescription volumes of all antiobesity agents have since declined. In contrast, the quarterly volume of all prescription medications in Canada rose steadily over the study period.

image

Figure 3. Quarterly antiobesity and overall drug prescriptions in Canada (1998 to 2004).

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Discussion

  1. Top of page
  2. Abstract
  3. Introduction
  4. Research Methods and Procedures
  5. Results
  6. Discussion
  7. Acknowledgement
  8. References

In summary, despite the continued rise in overweight and obesity prevalence in Canada and the recent emphasis being placed by the media, medical profession, and governmental agencies on the treatment of this chronic condition, the annual proportion of total office visits related to obesity and overweight has not increased substantially in the past 5 years. In addition, the number of prescriptions dispensed nationally for antiobesity agents peaked in 2001 and now appears to be declining. In contrast, the total number of office visits and prescriptions dispensed for all medical conditions increased over the study period, suggesting that the observed obesity-related trends were not part of a general trend in the number of office visits and prescription rates.

There are a number of potential explanations for these results. Despite a wealth of evidence linking excess body fat to numerous chronic medical conditions, both physicians and patients may not regard the treatment of obesity and overweight as a health priority (21, 22). Previous data suggest that physicians underreport the prevalence of obesity and offer counseling to only 25% to 50% of eligible patients (21). Physicians may view obesity not as a true disease but rather as a personal failing (23). They may avoid discussing weight for fear of offending the patient or feel a sense of complacency, which may be reinforced by a lack of effective therapies. Lack of time, remuneration, and expertise are additional barriers to addressing weight-related issues (24).

Patients may not necessarily ask for the help of a physician to lose weight or may seek alternative means to lose weight. In the U.S., 15% to 35% of individuals are trying to lose weight at any given time, and consumers spend an estimated 30 to 50 billion dollars annually in efforts to lose weight, including fad diets and structured commercial weight loss programs (25). Fear of being treated disrespectfully does not seem to be a major barrier to patients seeking physician help to lose weight (26). Rather, dissatisfaction with physician expertise in weight loss strategies and physician interest in treating weight-related issues seems to be important concerns (26).

The use of antiobesity medications is likely declining because current agents have suboptimal efficacy, high relative costs, and side effect profiles that limit their practical utility. A meta-analysis of 1-year randomized controlled trials of orlistat and sibutramine reported mean placebo-subtracted differences of 2.9% (95% CI, 2.3% to 3.4%) with orlistat and 4.6% (95% CI, 3.8% to 5.4%) with sibutramine (20). Most importantly, studies were limited by very high attrition rates, averaging 33% with orlistat and 48% with sibutramine. In addition, orlistat commonly causes gastrointestinal adverse effects, and sibutramine, which raises blood pressure and pulse rate, is contraindicated in patients with uncontrolled hypertension. Cardiovascular toxicity is a potential concern, and a large, multicenter trial examining the effect of the drug on cardiovascular endpoints is now underway (27).

There are a number of important limitations to this study. First, the results depend on the accuracy of data recording, and no published validation studies have been reported for the CDTI or the CompuScript databases. However, such databases have been used extensively in prior peer-reviewed publications (21, 28, 29). Physicians are remunerated for their time, and there is a large annual drop-out rate, both of which may limit the generalization of the CDTI sample. Second, the study period of 5 years was relatively short in duration, and the observed trends cannot be generalized to previous time periods. However, it is during the last several years that the obesity epidemic has received the greatest amount of media and medical press and would be expected to have had the largest impact on the frequency of office visits and drug prescriptions. Finally, limited clinical information was available on individual patients, including a lack of anthropometric data.

Effective preventative and therapeutic strategies are urgently needed to address the obesity pandemic and will require the concerted efforts of individual patients, the medical profession, governmental agencies, and key sectors of society. Physicians need to play a key role in raising awareness, promoting lifestyle modification, and emphasizing to their patients that even relatively small amounts of weight loss are beneficial. Safer and more effective drug therapies are required, particularly for severely obese patients who are unable to exercise or lose weight through non-pharmacological means. There are no simple solutions to the obesity epidemic; however, these are vital initial steps that need to be taken to begin to address this important public health concern.

Acknowledgement

  1. Top of page
  2. Abstract
  3. Introduction
  4. Research Methods and Procedures
  5. Results
  6. Discussion
  7. Acknowledgement
  8. References

We thank IMS Health Canada for providing the data used in this study. There was no funding/outside support for this study.

Footnotes
  • 1

    Nonstandard abbreviations: CDTI, Canadian Disease and Therapeutics Index; CI, confidence interval.

References

  1. Top of page
  2. Abstract
  3. Introduction
  4. Research Methods and Procedures
  5. Results
  6. Discussion
  7. Acknowledgement
  8. References