Interventional pain blocks in Ontario: a population-based cross-sectional study on 2019 procedural volumes, clustering, and physician billings

Purpose Multidisciplinary chronic pain management includes pharmacologic, psychological, and interventional strategies. In Canada, the use of interventional pain blocks (PBs) has increased in recent years. We sought to determine the distribution and clustering of PBs among physicians in Ontario, and to examine differences in the patient and physician characteristics by volume of PBs administered. Methods We conducted a population-based cross-sectional study of PBs administered for chronic pain to Ontario residents between 1 January and 31 December 2019. Our primary outcome was the total number of PBs administered in an outpatient setting for chronic pain by eligible physicians. We used Lorenz curves, overall and stratified by PB type and physician specialty, to examine clustering of PBs among physicians, and compared patient and physician characteristics using standardized differences. Results Among physicians who provided PBs, provision was highly clustered, with the top 1% of physicians providing 39% of blocks. In these high-volume PB providers, the majority of whom were general practitioners (88.4%), PBs made up the vast majority (median [interquartile range (IQR)], 87% [84–89]) of their billings, with the majority of the patients in their practices (63.0%) receiving at least one PB in 2019. Patients who received a PB from a high-volume provider had a higher annual frequency of visit for PBs (median [IQR], 10 [3–23]) and number of PBs administered per visit (median [IQR], 5 [4–6]). Conclusion Pain block administration is highly clustered in Ontario, with many patients receiving PBs in ways that are not supported by best evidence. Further research is required to determine whether the Ontario fee-for-service model of billing has created a suboptimal use of these health care resources.