Identifying Complex Patients Using Adjusted Clinical Groups Risk Stratification Tool

Published: June 7, 2022
Category: Bibliography
Authors: J Verloop, M Bruijnzeels, M Fiocco, M Numans, S Girwar, S Sutch
Countries: USA
Language: English
Types: Care Management, Diagnoses, Population Health
Settings: PCP



To produce an efficient and practically implementable method, based on primary care data exclusively, to identify patients with complex care needs who have problems in several health domains and are experiencing a mismatch of care. The Johns Hopkins ACG System was explored as a tool for identification, using its Aggregated Diagnosis Group (ADG) categories.

Study Design

Retrospective cross-sectional study using general practitioners’ electronic health records combined with hospital data.


A prediction model for patients with complex care needs was developed using a primary care population of 105,345 individuals. Dependent variables in the model included age, sex, and the 32 ADGs. The prediction model was externally validated on 30,793 primary care patients. Discrimination and calibrations were assessed by computing C statistics and by visual inspection of the calibration plot, respectively.


Our model was able to discriminate very well between complex and noncomplex patients (C statistic = 0.9; 95% CI, 0.88-0.92), whereas the calibration plot suggests that the model provides overestimates of complex patients.


With this study, the ACG System has proven to be a useful tool in the identification of patients with complex care needs in primary care, opening up possibilities for tailored interventions of care management for this complex group of patients. Utilizing ADGs, the prediction model that we developed had a very good discriminatory ability to identify those complex patients. However, the calibrating ability of the model still needs improvement.

ADG,retrospective,EHR,complex care

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