Inferior Clinical Outcomes for Patients with Medicaid Insurance After Surgery for Degenerative Lumbar Spondylolisthesis: A Prospective Registry Analysis of 608 Patients

Abstract

It remains unclear how type of insurance coverage affects long-term, spine-specific patient-reported outcomes (PROs). This study sought to elucidate the impact of insurance on clinical outcomes after lumbar spondylolisthesis surgery. The prospective Quality Outcomes Database registry was queried for patients with grade 1 degenerative lumbar spondylolisthesis who underwent single-segment surgery. Twenty-four-month PROs were compared and included Oswestry Disability Index, Numeric Rating Scale (NRS) back pain, NRS leg pain, EuroQol-5D, and North American Spine Society Satisfaction. A total of 608 patients undergoing surgery for grade 1 degenerative lumbar spondylolisthesis (mean age, 62.5 ± 11.5 years and 59.2% women) were selected. Insurance types included private insurance (n= 319; 52.5%), Medicare (n= 235; 38.7%), Medicaid (n= 36; 5.9%), and Veterans Affairs (VA)/government (n= 17; 2.8%). One patient (0.2%) was uninsured and was removed from the analyses. Regardless of insurance status, comparedtobaseline, all 4 cohorts improved significantly regarding ODI, NRS-BP, NRS-LP, and EQ-5D scores (P< 0.001). In adjusted multivariable analyses, compared with patients with private insurance, Medicaid was associated with worse 24-month postoperative Oswestry Disability Index (β= 10.2; 95% confidence interval [CI], 3.9-16.5; P = 0.002) and NRS leg pain (β=1.3; 95% CI, 0.3-2.4; P = 0.02). Medicaid was associated with worse EuroQol-5D scores compared with private insurance (β=-0.07; 95% CI-0.01 to-0.14; P = 0.03), but not compared with Medicare and VA/government insurance (P> 0.05). Medicaid was associated with lower odds of reaching ODI minimal clinically important difference (odds ratio, 0.2; 95% CI, 0.03-0.7; P = 0.02) compared with VA/government insurance. NRS back pain and North American Spine Society satisfaction did not differ by insurance coverage (P> 0.05). Despite adjusting for potential confounding variables, Medicaid coverage was independently associated with worse 24-month PROs after lumbar spondylolisthesis surgery compared with other payer types. Although all improved postoperatively, those with Medicaid coverage had relatively inferior improvements.