Discussion
This study aimed to assess the performance and utility of algorithms designed to detect SLE attributes by implementing them in a large, urban data network. We first examined if these algorithms identified SLE attributes more often in patients with a greater number of SLE encounters as a measure of their performance. We observed a positive association between the number of positive SLE attributes detected and the number of SLE encounters during the study period. Patients with three or more SLE encounters were identified with roughly 2.5–3 times the number of positive criteria than patients without any SLE encounters, suggesting that these algorithms may be useful in identifying criteria set attributes in cohorts of patients with SLE.10 Patients with three or more SLE encounters also displayed higher rates of algorithm-classified SLE when compared with the referent group in all three criteria sets during our subanalysis in patients with fragmented care, further supporting their efficacy in accurately detecting SLE attributes in EHR data. In our investigation of multisite EHR data distribution among patients with fragmented care, we demonstrated that a significant number of criteria and per cent of individuals with algorithm-classified SLE significantly increased when data were included from all CAPriCORN sites, suggesting that SLE-specific information is often missing from single healthcare sites.
We also noted important patterns among individual classification criteria that are important for understanding the algorithms’ performance in this dataset and their future use in population surveillance. First, we found a positive ANA in only 24% of patients with three or more SLE encounters. ANA is a laboratory test with high sensitivity and estimated to be positive in roughly 95% of patients with SLE.25 26 It is possible that many patients in the three or more SLE encounters partition did exhibit a positive ANA at other healthcare sites or third-party testing centre not included in CAPriCORN or prior to a site’s EHR implementation, as repeat testing of ANA is not recommended, nor has it been found to be clinically useful.25 27 Evidence of these positive tests would, therefore, be unlikely included in a structured data concept analysed by these algorithms and only found in provider assessments of patients. Specific to CAPriCORN, ANA tests may also not have been properly associated with a structured medical terminology, which would have also prevented its identification. Similar patterns of low detection were seen in other criteria such as alopecia, oral ulcers and arthritis. These attributes may be found more often in narrative documentation as opposed to standardised medical terminologies like ICD codes given that these attributes are often documented during the course of care but may not be coded for billing. Multimodal approaches for detection of concepts in EHR data that incorporate processing of unstructured data elements have been shown to perform better than using structured data alone.28 The low detection rates that we observed among some of the classification criteria suggest that these multimodal approaches may be a valuable addition to our algorithms to improve their sensitivity in detecting certain attributes. The opposite pattern was observed among other criteria, with extremely high rates of detection across all SLE partitions. For example, leucopenia, while detected significantly more often in patients with three or more SLE encounters, was still identified by the algorithms in 67% of patients without an SLE encounter. Leucopenia occurs in approximately half of all patients with SLE,29 with a multifactorial aetiology that can be difficult to attribute directly to SLE.30 Our algorithm for identifying leucopenia includes rules for excluding other aetiologies unrelated to SLE. However, the high rates of leucopenia detection we observed across the entire cohort suggest that this rules-based approach may not cover all possible confounding causes of leucopenia when implemented in a generalised data context like in CAPriCORN.
There are several strengths to our work and the data sources we used. First, the cohort retrieved from CAPriCORN, while containing a slightly higher proportion of white and female patients than recent census estimates of Chicago, represents a demographically diverse group of patients.31 Furthermore, the partition of patients with three or more SLE diagnosis encounters more frequently contained black or African American patients, consistent with recent epidemiological estimates of SLE in the USA32 and serving as a secondary data quality measure that supports accurate identification of patients with SLE. Finally, the data linkage strategies employed by CAPriCORN18 retained protected health information within each organisation while still achieving successful linkage across sites.
Our study is limited by certain characteristics inherent to EHR data and features of the dataset we used for this current work. Our ability to fully assess the algorithms’ performance in accurately identifying criteria set attributes is limited by the anonymisation of patients and the site from which data were obtained. Therefore, we were unable to manually review charts of patients retrieved from our query for disease activity, medications and laboratory procedures. As a result, some patients may have been unknowingly misclassified by our algorithms due to differences in the underlying elements used in the PCORnet data model from the data present at northwestern or variations in data between sites. Future work will focus on manually adjudicated cohorts from multiple healthcare organisations to comprehensively assess their performance in contexts like CAPriCORN. In relation to our proof-of-concept investigation into care fragmentation and information gain, we did not assess the degree to which missing SLE-related information at a patient’s topmost visited site impacted clinician decision-making and patient outcomes. While the presence of particular criteria can influence clinician recommendations for screening and intervention,33 we were unable to investigate the effect of missing information with the data available to us. Future work will focus on missing SLE information to investigate its role in poorer outcomes observed among patients with fragmented care.19
Our findings have several implications for surveillance and population health management of SLE. First, the higher rate of detection of all criteria among patients with more SLE diagnoses supports their potential use in identification and characterisation of patients for use in SLE registries and longitudinal surveillance systems. Normally, evaluation of a patient for the presence of SLE requires a sizeable amount of time and labour in identifying classification criteria and other clinical indicators of SLE. The algorithms implemented in this study could be used to supplement this process through automated detection of criteria for experts to assess without the need for reviewing patients’ entire medical record. Our proof-of-concept investigation into care fragmentation supports additional use cases for these algorithms beyond reduction of chart review burden. First, we were able to investigate a hypothesis that may explain poorer outcomes observed among patients with fragmented care19 and show that SLE-specific information was often missing at sites that patients visited most often. These findings and follow-up studies on the effects of missing information on patient outcomes could be used to inform healthcare organisation stakeholders on the effective design of EHR data architecture and interorganisational collaboration to optimise care for patients with SLE. We also demonstrated that a significant amount of SLE attributes were identified with multisite data inclusion even among patients without any documented SLE encounters. This may support future use of these algorithms in combination with coordination between local health networks to highlight patients for further evaluation and allow for earlier SLE detection, intervention and prevention of disease-related damage.33
In conclusion, our findings suggest that these algorithms maintained their ability to find true SLE attributes in broad data settings. We also observed criteria positivity rates that were different than expected among a select number of attributes, highlighting the need for multimodal data incorporation to allow for improved detection of attributes such as ANA that are nearly universally present in SLE and excluding confounding instances of others such as leucopenia. Finally, using structured data alone, we were able to demonstrate the utility of these algorithms by showing that a significant proportion of SLE-specific information is often missing at sites that patients visit most often, which may partially explain the disparity in outcomes observed among patients with fragmented care.19