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In Spine

STUDY DESIGN : Retrospective administrative claims database analysis.

OBJECTIVE : Identify distinct pre-surgery healthcare resource utilization (HCRU) patterns among posterior lumbar spinal fusion patients and quantify their association with post-surgery costs.

SUMMARY OF BACKGROUND DATA : Pre-surgical HCRU may be predictive of post-surgical economic outcomes and help health care providers to identify patients who may benefit from innovation in care pathways and/or surgical approach.

METHODS : Privately insured patients who received 1-2 level posterior lumbar spinal fusion between 2007-2016 were identified from a claims database. Agglomerative hierarchical clustering (HC), an unsupervised machine learning technique, was used to cluster patients by pre-surgery HCRU across 90 resource categories. A generalized linear model was used to compare two-year post-operative costs across clusters controlling for age, levels fused, spinal diagnosis, posterolateral/interbody approach, and Elixhauser Comorbidity Index.

RESULTS : Among 18,770 patients, 56.1% were female, mean age was 51.3, 79.4% had 1-level fusion, and 89.6% had inpatient surgery. Three patient clusters were identified: Clust1 (n = 13,987 [74.5%]), Clust2 (n = 4,270 [22.7%]), Clust3 (n = 513 [2.7%]). The largest between-cluster differences were found in mean days supplied for antidepressants (Clust1: 97.1 days, Clust2: 175.2 days, Clust3: 287.1 days), opioids (Clust1: 76.7 days, Clust2: 166.9 days, Clust3: 129.7 days), and anticonvulsants (Clust1: 35.1 days, Clust2: 67.8 days, Clust3: 98.7 days). For mean medical visits, the largest between-cluster differences were for behavioral health (Clust1: 0.14, Clust2: 0.88, Clust3: 16.3) and non-thoracolumbar office visits (Clust1: 7.8, Clust2: 13.4, Clust3: 13.8). Mean (95% CI) adjusted two-year post-operative costs were lower for Clust1 ($34,048 [$33,265-$34,849]) versus both Clust2 ($52,505 [$50,306-$54,800]) and Clust3 ($48,452 [$43,007-$54,790]), p < 0.0001.

CONCLUSIONS : Distinct pre-surgery HCRU clusters were identified characterized by greater utilization of antidepressants, opioids, and behavioral health services and these clusters were associated with significantly higher two-year post-surgical costs.

LEVEL OF EVIDENCE : 3.

Lerner Jason, Ruppenkamp Jill, Etter Katherine, Headd Jeffrey J, Bhattacharyya Samir, Menzie Ann M, Pracyk John B, McGuire Kevin J

2019-Sep-06