HEALTH INSURANCE DESIGN AS A DETERMINANT OF BARIATRIC SURGERY UTILIZATION

Abstract

Background: Bariatric surgery is the most effective treatment for severe obesity, resulting in much larger and longer-lasting weight loss compared with those seen with other treatment options. It also results in significant improvements in several weight-related comorbidities. Despite these favorable outcomes, bariatric surgery remains underused in the United States. Objective: The goal of this dissertation was to investigate the impact of insurance-related factors on the access and utilization of bariatric procedures. The goal was achieved via three studies. The first study examined temporal changes in patient characteristics and insurer type mix among adult bariatric surgery patients in Southeastern Pennsylvania, as well as the associations between payer type, insurance plan type, cost-sharing arrangements (among traditional Medicare beneficiaries), and bariatric surgery utilization. The second study investigated whether there is an association between precertification criteria, such as 3-6 months preoperative supervised medical weight management (MWM), and documented 2-year weight history and the likelihood of undergoing bariatric surgery. The third study examined whether there is an association between insurance-mandated MWM requirement, as well as cardiology and pulmonology evaluations and short-term inpatient healthcare utilization. Data Source: Pennsylvania Health Care Cost Containment Council’s (PHC4) databases in Southeastern Pennsylvania during 2014-2018. Study Population: In Study 1, all adult patients in the PHC4 dataset who underwent the most common types of bariatric surgery during 2014-2018 (N = 14,348) and a 1:1 matched sample of surgery patients and those who were eligible for surgery but did not undergo surgery were identified. In Study 2, privately insured patients within the PHC4 dataset who underwent bariatric surgery in 2016 and individuals who met the eligibility criteria but did not undergo surgery were identified and 1:1 matched (N = 1,054). The population of Study 3 consisted of all adult patients within the PHC4 dataset with a diagnosis of severe obesity who underwent the most common bariatric surgical procedures in 2016 and for whom the insurance-mandated precertification requirements were known (N = 2,717). Results: Over the five years, there was an increase in the proportion of Black individuals (37.1% in 2014 vs 43.0% in 2018), Hispanics (5.4% vs 8.0%), and Medicaid beneficiaries (18.5% in 2014 vs 26.9% in 2018) who underwent surgery. The odds of undergoing bariatric surgery based on payer type were statistically different (22% smaller odds) only between Medicare beneficiaries compared to privately insured individuals. There were significantly different odds of undergoing surgery based on insurance plan type within Medicare and private insurance payer categories. Individuals with traditional Medicare plans with no supplementary insurance and those with dual eligibility had smaller odds of undergoing surgery (42% and 32%, respectively) compared to those with private secondary insurance. The insurance requirement for 3-6 months MWM was associated with smaller odds of undergoing surgery (odds ratio [OR] = 0.459, 95% confidence interval [CI] 0.253 to 0.832, P = 0.010), after controlling for insurance plan type and the requirement for documented weight history. The documented weight history requirement was not a significant predictor of the odds of undergoing surgery (P = 0.132). The requirement for MWM, as well as pulmonology and cardiology examinations, were not associated with the patient length of stay, the number of all-cause rehospitalizations, and the number of all-cause rehospitalization days, after adjusting for patient age, sex, race, ethnicity, the Elixhauser Comorbidity Score, type of the surgery, facility where the surgery was performed, primary payer type, and the estimated median household income. The absence of the precertification requirement for pulmonology and cardiology evaluations was associated with smaller odds of rehospitalizations with common cardiac and pulmonary conditions during the study period, (OR = 0.43, 95% CI 0.23 to 0.80, P = 0.008), after controlling for patient age, sex, race, ethnicity, estimated median household income, and the Elixhauser Comorbidity Score. Conclusions and Significance: Medicaid expansion in Pennsylvania appears to have improved access to bariatric surgery among Black and Hispanic individuals. Nevertheless, insurance plan type, cost-sharing arrangements, and precertification requirements, such as insurance-mandated 3-6 months of MWM requirement, remain key determinants for the access and utilization of bariatric surgery. Additionally, the MWM requirement, as well as the preoperative cardiology and pulmonology evaluations, were not associated with a reduction in inpatient healthcare utilization during the first postoperative year. Careful examination of the bariatric surgery benefit design and application of value-based insurance design to bariatric surgery may improve the access to this potentially life-saving surgery for many Americans.