Obesity has contributed to long-term prescription opioid use in the United States, according to the results of a longitudinal study published in the American Journal of Preventive Medicine.
Studies have shown an association between obesity and several conditions that increase the risk for chronic pain, but the effect of obesity on long-term prescription opioid use has not yet been determined.
Data from 89,629 individuals (50.2% men) who participated in the Medical Expenditure Panel Survey from 2000 to 2015 were used to assess the association between obesity and long-term prescription opioid use in the United States. Respondents aged 30 to 84 years with a body mass index (BMI) ≥17.5 kg/m2 and ≤50 kg/m2 who had no relevant data missing and no history of opioid use for at least approximately 9 months at the start of the study were included. Respondents with a current or recent cancer diagnosis or pregnancy were excluded. The average age of included individuals was 50.9±13.7 years.
Survey data were self- or proxy-reported in 5 rounds of interviews approximately 5 months apart and the second interview was used as baseline. In this study, incident long-term prescription opioid use was defined as opioid use in ≥2 of the 3 interviews after baseline, which spanned an average of 15 months. Pharmacy providers gave information regarding opioid medication type, strength, and quantity. BMI was categorized as underweight (17.5-19.9 kg/m2), normal weight (20-24.9 kg/m2), overweight (25-29.9 kg/m2), or obesity class 1 (30-34.9 kg/m2), class 2 (35-39.9 kg/m2), or class 3 (40-49.9 kg/m2). The underweight categorization was expanded from the standard range to account for illness-related weight loss.
Among all included respondents, 2.2% had incident long-term prescription opioid use. After adjusting for covariates, an individual’s BMI classification was strongly and linearly associated with an increased likelihood of long-term prescription opioid use compared with adults with normal weight (overweight: adjusted odd ratio [aOR], 1.24 [95% CI, 1.07-1.44]; obesity class 1: aOR, 1.74 [95% CI, 1.49-2.03]; obesity class 2: aOR, 2.10 [95% CI, 1.69-2.59]; obesity class 3: aOR, 2.58 [95% CI, 2.06-3.24]). The association between obesity and incident use of high-dose opioids was stronger than its association with incident use of low-dosage opioids.
At the population level, 27% of incident long-term prescription opioid use was attributable to having a BMI above normal. Based on these data, it may be inferred that “approximately one quarter of all incident long-term prescription opioid use in the US could be averted in a scenario in which all individuals with a BMI of overweight or obese instead lost weight and entered the normal BMI category,” the researchers noted.
Limitations to this study included that it relied on self-reported data and did not capture information regarding opioid use prior to the 9-month period before baseline. Individuals with chronic pain were not excluded, which also may have introduced a bias for individuals with illness-related weight gain.
Stokes A, Lundberg DJ, Hempstead K, Berry KM, Baker JF, Preston SH. Obesity and incident prescription use in the U.S., 2000-2015 [published online March 27, 202]. Am J Prev Med. doi:10.1016/j.amepre.2019.12.018