Obese patients who undergo laparoscopic bariatric surgery use significantly fewer medications in the long term than those who do not have the surgery, according to an analysis of national insurance claims. The yearly savings in prescription drug costs four years after surgery was $1,500.
“The decreased rate of prescription drug utilization over four years among patients who underwent surgery compared to those in the nonsurgery cohort may be due to an improvement in comorbid burden post-surgery,” said John Morton, MD, president of the American Society for Metabolic and Bariatric Surgery (ASBMS) and director of bariatric surgery at Stanford University School of Medicine, in Stanford, Calif. Dr. Morton presented the study at Obesity Week 2014 (abstract a103).
Previous research examining the effect of bariatric surgery on health care costs has been mixed. An employer claims database study conducted between 1999 and 2005 estimated the cost of bariatric surgery to be between $17,000 and $26,000, and concluded that downstream savings offset initial costs in two to four years (Am J Manag Care 2008;14:589-596).
Another study, a six-year follow-up of 30,000 obese patients who underwent bariatric surgery between 2002 and 2008 and a matched nonsurgical cohort, concluded that bariatric surgery does not reduce overall health care in the long term (JAMA Surgery 2013;148:555-562). Dr. Morton pointed out that this latter study predated the accreditation of bariatric surgical centers and use of the laparoscopic approach, both of which have demonstrated lower complications and costs. The study also had a follow-up rate of only 7%.
In the new study, investigators analyzed pharmacy costs from the MarketScan Commercial Claims and Encounters database for patients who had a diagnosis of obesity between Jan. 1, 2007 and Dec. 31, 2008. They compared data for patients who underwent laparoscopic bariatric surgery (laparoscopic gastric band or Roux-en-Y gastric bypass; n=2,700) and a cohort of similar matched patients who did not (n=2,700), with 100% follow-up at four years. This nationwide database contains data for approximately 56 million covered lives from all 50 states.
In their sample, the investigators did not include patients if they had evidence of inflammatory bowel disease, familial adenomatous polyposis, noninfectious colitis, cancer of the digestive organs or peritoneum during the year before the index period. Patients had to be continuously enrolled in a health insurance plan from one year pre-index period to four years post-index. The two patient groups were similar, but individuals who had the surgery had higher rates of cardiovascular disease (65.9% vs. 56.7%), acid reflux (24.7% vs. 11.1%) and sleep apnea (39.6% vs. 18.7%).
Patients in the surgery group had higher total pharmacy costs at one year after surgery or post-index year ($3,098 vs. $2,303), but lower costs in the next three years. At four years, prescription drug costs were $8,411 for patients who had bariatric surgery and $9,900 for those who did not. After adjusting for pre-index pharmacy costs and comorbidities, pharmacy costs were 22.6% lower for surgery cases than controls at four years post-index (cost ratio, 0.774; 95% confidence interval, 0.728-0.821; P<0.0001).
Reductions were driven by lower antidiabetic, antihypertensive and cardiovascular drug prescription costs. Whereas the proportion of patients receiving cardiovascular prescriptions declined among those who had surgery from one year to four years post-index (42% vs. 40%), it increased among nonsurgical patients (34% vs. 46%). The same trend was seen for antihypertensive prescriptions (surgery, 66% to 59%; no surgery, 59% to 70%) and antidiabetic prescriptions (surgery, 34% to 21%; no surgery, 30% to 38%).
According to Dr. Morton, the first-year increase for the surgery group was likely attributable to medications that patients sometimes receive after surgery, such as pain medicines and proton pump inhibitors. “Whatever cost savings there were around diabetic medications or high blood pressure medications were lost because of those other medications,” Dr. Morton said.
Bariatric surgery also affected the total number of prescription drugs used by patients. After multivariate adjustments, at four years post-index, the number of antidiabetic prescriptions was 74% lower among surgery cases than nonsurgical cases. Similar trends were seen for the number of antihypertensive prescriptions (48.3% lower) and number of cardiovascular prescriptions excluding antihypertensives (48.9% lower).
“It is likely that additional medication cost savings may be maintained years following surgery,” Dr. Morton said.
According to Robin Blackstone, MD, medical director of Scottsdale Healthcare Bariatric Center, in Scottsdale, Ariz., who was not involved in the study, the research is extremely relevant.
“We are all anxious to prove the value of bariatric surgery,” she said, noting that the study established its effectiveness in reducing medication costs.
Dr. Morton said he expected the Affordable Care Act to increase the rates of bariatric surgery. Only 22 states cover bariatric surgery, but a joint initiative from ASMBS and the American College of Surgeons will address expanding coverage to all 50 states. According to Dr. Morton, his study provides evidence that this expansion will be valuable.