b"CARES 2022 Annual Report Table 2. Concordance of Race/Ethnicity Data in CARES with Self-Reported Data in Medicare Files. Figure used with permission of Elsevier from Chan PS et al. Race and ethnicity data in the cardiac arrest registry to enhance survival: Insights from medicare self-reported data. Resuscitation. 180:64-67 (2022). Permission conveyed through Copyright Clearance Center Inc. Dialysis Clinic Data LinkageData linkage can also be utilized to focus on a target sub-population. Out-of-hospital cardiac arrests are common in outpatient dialysis clinics, and immediate provision of CPR improves patient outcomes. However, there is a disparity in the rate at which Black patients receive CPR from dialysis clinic staff compared to White patients. By linking CARES to the Medicare Annual Dialysis Facility Report registry, researchers examined the role of dialysis facility resources and patient factors. OHCAs occurring in dialysis clinics were identified in CARES and information was extracted from the CMS's Dialysis Facility Compare online tool to obtain facility-level variables, such as characteristics, quality, and performance. Each CARES case was then linked to the corresponding dialysis facility care reports for the matching facility and year of the event. The analysis of the linked dataset revealed that Black cardiac arrest patients were dialyzed in larger facilities (26 versus 21 dialysis stations; P0.001) with fewer registered nurses per station (0.29 versus 0.33; P0.001), lower quality scores (6.8 versus 6.3; P=0.04), and higher proportions of patients with a history of cardiac arrest (41% versus 35%; P0.001), HIV/hepatitis B, and Medicaid-enrolled patients compared to White patients (15% versus 11%; P0.001). After accounting for these differences and other factors, the racial disparity in CPR provision between Black and White patients persisted, with Black patients being less likely to receive CPR (OR=0.45; 95% CI, 0.27 to 0.75). The disparity was also more pronounced among older patients than younger patients (Figure 3).Enabling healthcare advancementthrough the provision of data linkageThe fragmentation of data in the United States presents challenges in answering critical pu blic health questions related to out-of-hospital cardiac arrest (OHCA) and overa ll public health. The use of the CARES registry and techniques like deterministic and probabilistic matching can enable researchers to link registrydata with other datasets and answer questions regarding OHCA that are not readily available.46"