(D) Changes in Medication Use Before and After Bariatric Surgery in Older Adults

Publication Number: 294

Background: Over one-quarter million bariatric surgeries are performed each year in the US; however, there are very limited data on changes in medication use in the older adult population. An evaluation in this population is necessary as the effects of bariatric surgery can further impact changes in drug distribution, metabolism, and excretion associated with increased age.

Objectives: To evaluate trends in utilization of antihypertensives, glucose-lowering, and antihyperlipidemic medications as well as total number of medications among patients aged ≥66 years old who underwent bariatric surgery.

Methods: This study utilized 5% and 15% Medicare fee-for-service claims databases from 2011-15 and 2016-18, respectively. Patients aged ≥66 years old who underwent Roux-en-Y gastric bypass [RYGB] or sleeve gastrectomy [SG] with 360 days of continuous enrollment before and after the surgery date were included. The proportion of antihypertensives, glucose-lowering agents, and antihyperlipidemic medications were identified using Anatomical Therapeutic Chemical (ATC) classification system in 30 days intervals. Additionally, mean number of unique ATC Level 4 codes (indication medication class) were also described. Segmented regression was used to evaluate changes in medication use immediately before compared to one year after surgery.

Results: A total of 1,647 patients underwent bariatric surgery in which 588 (35.7%) underwent RYGB and 1,059 (64.3%) underwent SG. The mean age of the population was 69.6 years old with the majority being female (69.8%). Among included patients, 95.3% have hypertension, 63.6% have type 2 diabetes, and 88.5% have hyperlipidemia with a mean number of 8.29 unique medications in the 90 days prior to bariatric surgery. Compared to immediately before bariatric surgery, there was a 26.9%, 53.9%, and 16.3% reduction in the proportion of patients treated with antihypertensives, glucose-lowering agents, and antihyperlipidemic medications, respectively, one year after surgery. There was also a 36.9% reduction in mean number of unique medications. There was no difference between RYGB and SG in any analysis.

Conclusions: There is a reduction in medication use following bariatric surgery in older adults with no difference between RYGB vs. SG, though between surgery type findings may be limited by sample size.