Observational Study of the Distribution and Diversity of Interventional Pain Procedures Among Hospitals in the State of Iowa

摘要

Background: Critical access hospitals represent 61% of hospitals in the rural United States, and68% of hospitals in Iowa. The role of small hospitals, such as critical access hospitals, in providinginterventional chronic pain procedures is unknown.Objectives: We evaluated whether: a) the diversity of interventional pain procedures offered byhospitals is related to their size and is attributable principally to lumbosacral epidural injections; b)critical access hospitals contribute substantively to the count and diversity of pain procedures; andc) whether most interventional pain procedures performed at hospitals’ facilities are performed byrelatively few proceduralists or by the cumulative activity of many clinicians.Study Design: This research involved an observational cohort design with a sample size of n =283,940 interventional pain procedures.Setting: Data were collected from hospital-owned facilities in the state of Iowa from July 2012through September 2017.Methods: The diversity of types of interventional pain procedures performed statewide wasquantified in terms of the relative proportions of procedures at each hospital using the Herfindahlindex. Bilinear weighted least squares regression quantified the relationship between the inverseof the Herfindahl and the percentage of procedures that were lumbar or caudal epidural. Kendalltau concordances quantified the relationship between counts of interventional pain procedures andhospital size. Using a blinded version of the National Provider Identifier of the clinician with primaryresponsibility for performing the principal procedure of the ambulatory visit, we calculated thepercentage shares of interventional pain procedures performed by the 1% and 5% of proceduralistswho performed the most procedures.Results: The diversity of types of procedures substantively differentiated among hospitals.Heterogeneity among hospitals in the proportion of procedures that were lumbar or caudalepidural injections substantively contributed to the heterogeneity among hospitals (P < .001).Hospitals performing more procedures tended to have greater diversity of types of procedures(P < .001). However, the strength of the concordance was small (Kendall τb = 0.332), showingsubstantial heterogeneity among hospitals. The 82 critical access hospitals statewide cumulativelyaccounted for 23.9% of interventional pain procedures. The critical access hospitals’ procedureswere mostly (67.7%) lumbar or caudal epidural injections (P < .001), greater than the 48.9% ofthe other 41 hospitals (P < .001). Procedures were concentrated among proceduralists. The 1.0%of the proceduralists performing the most procedures performed 64.8% of procedures. The 5.0%of proceduralists performing the most procedures performed 87.7% of procedures.Limitations: The data are procedures were performed in hospital-owned facilities of Iowa.