The relationship between body weight and drug costs: An Italian population-based study

This study determined the prevalence of 3 categories of body mass index (BMI)--normal weight, overweight, and obesity--in a sample of subjects from general clinical practice in Ravenna, Italy, and evaluated the impact of comorbidities associated with overweight and obesity on the costs of drug treatment from the perspective of the Italian national health system.

This was a cross-sectional study conducted in a sample of subjects aged > or =18 years from 10 general practices in the Ravenna local health unit (LHU) in 2001-2002. Subjects were invited to attend a screening visit at which weight and height were measured for determination of BMI, blood pressure was measured, and a fasting blood sample was obtained for laboratory tests. The screening examinations were conducted by 2 physicians at a dedicated practice. Normal weight, overweight, and obesity were defined as a BMI < or =24.9, between 25 and 29.9, and > or =30 kg/m2, respectively. The costs of classes of drug treatment that were reimbursable to the LHU in the 12 months before the screening examination were evaluated using the Ravenna LHU administrative databases. Drug treatments were classified as antihypertensive agents, statins, NSAIDs, gastroprotective drugs, antidiabetic agents, respiratory drugs, antiplatelet agents, antidepressants, and all other drugs. The data were analyzed by age group.

Of the 2622 subjects in the sample, 1256 (47.9%) had a normal BMI, 918 (35.0%) were overweight, and 448 (17.1%) were obese. The prevalence of overweight and obesity increased in relation to age up to 50-59 years (P < 0.001), after which it remained stable. Overweight and obese subjects had significantly more exposure to individual and multiple drug treatments compared with subjects with normal weight (P < 0.001). By type of drug treatment, 16.7% of normal-weight subjects, 35.6% of overweight subjects, and 51.8% of obese subjects were exposed to antihypertensives; 4.1%, 8.7%, and 12.1%, respectively, to statins; 14.2%, 22.0%, and 29.0% to NSAIDs; and 1.0%, 4.7%, and 9.4% to antidiabetics. The mean annual cost of drugs was Euro 132.71 in normal-weight subjects, Euro 246.19 in overweight subjects, and Euro 335.64 in obese subjects (P < 0.001). After adjustment for differences in age distribution between the study sample and the overall population of Ravenna, the estimated excess drug costs associated with overweight and obesity in Ravenna were Euro 5,661,126.20 and Euro 6,688,099.85, respectively.

In this study sample, the prevalence of overweight increased by approximately 10% and the prevalence of obesity increased by approximately 5% with each decade of age up to 60 years, after which it remained stable at approximately 40% and approximately 20%, respectively. Overweight and obesity were associated with increased drug exposure and costs in all age groups considered.