The Charlson Comorbidity Index to Identify future high cost Patients (PLOS, 2014)

Reducing health care costs requires the ability to identify patients most likely to incur high costs.

The objective of this study was to evaluate whether comorbidity, as assessed by the Charlson comorbidity index during one year, could be applied to a large population to identify those patients who would incur high health care costs in a subsequent year.

The performance of the comorbidity index in predicting future costs was compared to prior year total costs, a usual benchmark; to the Diagnostic Costs Groups (DCG), one commonly used population-based risk adjustment strategy ; and to prior hospitalizations. Since mental health conditions commonly co-occur with chronic illness and are known to increase costs, but are not included in the standard Charlson index (except for depression and dementia), their contribution to total costs was also evaluated.