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A systematic search of the medical literature was performed on April 6, 2007. The search, limited to human subjects and English language journals included Ovid, UpToDate®, and the Cochrane database. Search terms included obesity, pharmacotherapy, diabetes, insulin resistance, hypertension, dyslipidemia, orlistat, sibutramine, and phentermine.

Long-term weight loss maintenance is a challenge in the treatment of obesity, especially in the primary care setting where time constraints and reimbursement are major issues. The prevalence of obesity is on the rise world wide, and is a major public health concern. There is little doubt that this disease needs to be treated; however the traditional strategies of weight reduction by behavior modification and physical activity have poor long-term outcomes, primarily as a result of lack of compliance.1 Considerable evidence suggests that even a modest weight reduction of 5% to 10% of initial body weight can significantly impact the morbidity and mortality of obese patients.2 Obesity is a multifactorial disease requiring individually tailored treatment strategies. Pharmacotherapy plays an important role in the appropriate patient.

Body Mass Index

Body mass index (BMI) is the most practical way to evaluate weight. It is calculated (metric formula) as follows:

  • BMI = (body weight in kilograms) ÷ (height in meters)2

When measurements are recorded in pounds and inches, the following equation may be used:

  • BMI = [(body weight in pounds) × 705] ÷ (height in inches)2

BMI is relatively unaffected by height, and is highly correlated with body fat. A BMI of 18 to 25 kg/m2 is considered normal or ideal body weight. Patients with a BMI of 25 to 30 kg/m2 are low risk, while those with a BMI of 30 to 35 kg/m2 are moderate risk. Patients with a BMI of 35 to 40 kg/m2 are at high risk, and those with a BMI above 40 kg/m2 are at very high risk for morbidity and mortality from their obesity. Irrespective of BMI, health risk is increased by more abdominal fat distribution (increased waist to hip ratio) (Fig. 24-1).

Figure 24-1.

Algorithm for the assessment and stepwise management of the overweight or obese adult. *BMI and waist circumference cutoff points are different for some ethnic groups. LDL, low-density lipoprotein; HDL, low-density lipoprotein.


The Swedish Obese Subjects Study followed untreated obese subjects with an average BMI of 38 kg/m2 for 2 years.3 The 2-year incidence of the following comorbidities were:

  • • Hypertension: 13.6%
  • • Diabetes mellitus: 6.3%
  • • Hyperinsulinemia: 6.3%
  • • Hypertriglyceridemia: 7.7%
  • • Low serum high-density lipoprotein (HDL) cholesterol: 8.6%
  • • Hypercholesterolemia: 12.1%

A comparison of one of the above comorbidities, in the general population, yielded a 29% incidence rate ...

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