Table 2

Identification of transfers, thrombolysis and EVT treatments, by patient identification strategy

	Interhospital transfer, n (%)	Thrombolysis, n (%)	EVT, n (%)
Ischaemic stroke observations with ICD-9-CM, ICD-10-CM or MS-DRG (ie, Union) n=365 099	18 859 (5.2) ICD-9-CM/ICD-10-CM MS-DRG	32 506 (8.9) ICD-9-CM/ICD-10-CM ICD-9-PCS/ICD-10-PCS MS-DRG CPT	7691 (2.1) ICD-9-PCS/ICD-10-PCS MS-DRG
Ischaemic stroke observations with ICD-9-CM, ICD-10-CM or MS-DRG (ie, Union) n=365 099	18 855 (5.2) ICD-9-CM/ICD-10-CM	31 932 (8.7) ICD-9-CM/ICD-10-CM ICD-9-PCS/ICD-10-PCS CPT	6674 (1.8) ICD-9-PCS/ICD-10-PCS
Ischaemic stroke observations with ICD-9-CM, ICD-10-CM (with or without MS-DRG) n=365 026	18 855 (5.2) ICD-9-CM/ICD-10-CM MS-DRG	32 433 (8.9) ICD-9-CM/ICD-10-CM ICD-9-PCS/ICD-10-PCS MS-DRG CPT	7691 (2.1) ICD-9-PCS/ICD-10-PCS MS-DRG
Ischaemic stroke observations with ICD-9-CM, ICD-10-CM (with or without MS-DRG) n=365 026	18 855 (5.2) ICD-9-CM/ICD-10-CM	31 862 (8.7) ICD-9-CM/ICD-10-CM ICD-9-PCS/ICD-10-PCS CPT	6674 (1.8) ICD-9-PCS/ICD-10-PCS
Ischaemic stroke observations with both ICD-9-CM or ICD-10-CM and MS-DRG (ie, overlap) n=320 187	5442 (1.7) ICD-9-CM/ICD-10-CM MS-DRG	27 874 (8.7) ICD-9-CM/ICD-10-CM ICD-9-PCS/ICD-10-PCS MS-DRG	7418 (2.3) ICD-9-PCS/ICD-10-PCS MS-DRG
Ischaemic stroke observations with ICD-9-CM or ICD-10-CM only* n=44 839	779 (1.7) ICD-9-CM/ICD-10-CM	2172 (4.8) ICD-9-CM/ICD-10-CM ICD-9-PCS/ICD-10-PCS CPT	273 (0.6) ICD-9-PCS/ICD-10-PCS
Ischaemic stroke observations with MS-DRG only† n=73	0 (0) MS-DRG	73 (100) MS-DRG	0 (0) MS-DRG

*MS-DRGs for these patients are presented in the online supplemental material.
†Primary ICD-9-CM/ICD-10-CM codes for these patients are presented in the online supplemental material.
CPT, Current Procedural Terminology; EVT, endovascular thrombectomy; ICD-CM, International Classification of Disease, clinical modification; ICD-PCS, International Classification of Disease, procedural coding system; MS-DRG, Medicare Severity-Diagnosis-related Group.