209. Does increased regional discretionary spending correlate with safety in spine surgery among Medicare beneficiaries

Abstract

BACKGROUND CONTEXT Spine surgery in Medicare patients has increased in recent years and its use is variable across geographic regions. Corresponding wide variation in costs are also well-documented. Provider care intensity, a marker for discretionary care (eg, unnecessary imaging, tests, injections, and visits), is the component of spending variation that is independent of patient severity, age, and regional pricing. It is unknown if greater provider care intensity is associated with improved safety, as we might expect from value-based care. PURPOSE To determine if increased provider care intensity was associated with safety among five Medicare cohorts undergoing spinal surgery. STUDY DESIGN/SETTING Retrospective analysis of Medicare claims, 2013-2017. PATIENT SAMPLE We included beneficiaries (age 65+) undergoing inpatient spinal surgery as defined by the Center for Medicare and Medicaid Innovation, including “cervical fusion,” “fusion, except cervical,” “anterior-posterior combined fusion,” “complex fusion,” and “back or neck surgery, except fusion.” Claims included variables on age, sex and race, as well as codes from the International Classification of Diseases, used to calculate the Charlson Comorbidity Index. Regional 90-day episode costs for the five cohorts ranged from a low of $32,384 for cervical fusion to a high of $123,388 for complex fusion. OUTCOME MEASURES Safety was measured as mortality, pulmonary embolism, deep vein thrombosis, and all-cause readmission over the first 90-days following surgery. METHODS Patients were classified by the Hospital Referral Region (HRR) where surgery occurred. Regions were grouped into quintiles based on the Dartmouth Atlas End-of-Life Expenditure Index (EOL), reflecting spending variation due to practice care intensity. Multivariable regression examined the association between care intensity and our safety measures, controlling for age, sex, race, and comorbidity. To further mitigate unobserved confounding by indication, we also added year and hospital fixed-effects parameters, and applied EOL as an instrumental variable. RESULTS Within each cohort, we observed a 4-fold variation in 90-day episode cost across HRRs. Spine-specific spending was correlated with EOL quintile, confirming that spending variation is due to provider care intensity more than pricing, age, or illness severity. Greater spending across EOL quintile was not associated with improved safety, and in-fact, was associated with significantly worse outcomes in some cohorts. For example, all-cause readmission was greater in the high spending quintile relative to the low spending quintile among the “Fusion, except cervical” cohort (14.2% vs 13.1%; OR 1.10; 95% CI 1.05 – 1.20; p CONCLUSIONS Wide variation in regional 90-day episode-of-care spine spending was not explained by differences in patient severity, age, or regional pricing. Hospitals in the highest spending quintile spent between $10,378 (back & neck) to $35,533 (complex fusion) more per patient than those in the lowest quintile, but increased spending did not result in enhanced safety. These findings point to inefficient and potentially wasteful use of health care resources, which should be a focus of payment reforms. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.