Introduction: The high cost of spine surgery may lead uninsured and underinsured patients to defer surgical intervention. Health insurance coverage in the United States expands at age 65 as people become eligible for Medicare. This expansion has a significant impact on overall utilization of health care and outcome studies have demonstrated associated positive health benefits; however, the impact of the insurance on the utilization of spinal surgery has not been previously described.

Methods: The study population included patients from the Hospital Cost and Utilization Project (HCUP) National Inpatient Sample (NIS) from 2000-2010 identified by ICD-9 diagnosis and procedure codes. A total of 639,172 patients were identified with diagnoses of spondylosis, spondylolisthesis, and other deferrable (non-urgent/emergent) spine conditions who underwent decompression surgery with or without fusion. Rates of surgery were tabulated by patient age, insurance status, income quartile, race, region, and hospital teaching status.

Results: We find a significant decline in spine surgery at ages 63 and 64 that recovers at age 65 (Figure 1). Using a linear regression model controlling for year by state fixed effects, the number of surgeries decreases by 7.6% for 63-year-old patients and 12.6% for 64-year-old patients (p<0.001). Rate of surgery for patients aged 66-68 is increased 3.4% (p<0.05) beyond the baseline trend. Lower income quartiles experienced greater declines in surgery rate prior to age 65 (Figure 2).

Conclusions: This study identifies a significant decrease in deferrable spine surgery just prior to the expansion in insurance status with Medicare eligibility at age 65. As the Affordable Care Act broadens insurance coverage, these results suggest patients may elect to undergo surgery at an earlier age. This may lead to an expansion in total surgeries or a shifting to operating on younger patients, which may result in improved outcome and diminished morbidity and loss of work from inadequately treated spine disease.

Patient Care: This project will inform neurosurgeons about the effect of insurance status and socioeconomic factors underlying a patient's decision to defer recommended spine surgery. Given the upcoming broad expansion in insurance with the enactment of the Affordable Care Act, these results provide evidence that obtaining insurance may lead to increased demand for spine surgery in patients who may have chosen to defer surgery until Medicare eligibility. This may lead to an overall increase in demand for spine surgery or a shift of patients towards having surgery at an earlier age with potentially fewer comorbidities and decreased severity of disease.

Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe the impact of Medicare eligibility on the rate of deferrable spine surgery, 2) Identify socioeconomic factors contributing to this observed trend, 3) Understand how to use administrative discharge data from the Hospital Cost and Utilization Project National Inpatient Sample to evaluate national surgical trends.

References: 1. Card D, Dobkin C, Maestas N. Does Medicare Save Lives? The Quarterly Journal of Economics 2009;124(2):597–636. 2. Schoenfeld AJ, Lurie JD, Zhao W, Bono CM. The effect of race on outcomes of surgical or nonsurgical treatment of patients in the Spine Patient Outcomes Research Trial (SPORT). Spine 2012;37(17):1505–15. 3. US Burden of Disease Collaborators. The state of US health, 1990-2010: burden of diseases, injuries, and risk factors. JAMA 2013;310(6):591–608.