| Geonhyeok Jeong, Ting Shi |
Abstract
Comorbidity refers to the presence of two or more medical conditions or disease in an individual at the same time. These conditions can either occur simultaneously or one can develop after the other. Comorbidity can complicate the diagnosis, treatment, and management of these conditions, as they may interact with each other and affect the overall health and well-being of the individual. Comorbidity indexes are commonly used in medical research and clinical practice to assess the burden of comorbid conditions in individuals. The calculation of comorbidity typically involves using a comorbidity index or scoring system to assign weights or scores to different comorbid conditions. This paper describes a custom SAS macro and R function which gives user the flexibility to customize the different comorbidity indexes and weights for the calculation.
Introduction
Some of the commonly used comorbidity indexes include: Charlson Comorbidity Index (CCI), Elixhauser Comorbidity Index (ECI), NCI Comorbidity Index, Washington University Head and Neck Comorbidity Index (WUHNCI), Simplified Comorbidity Score for a Patient with Non-Small Cell Lung Cancer (NSCLC) and others. All these measures involve using specified list of medical conditions identified from diagnoses codes and assign the weights for the comorbidities.
The published SAS codes or R packages have the diagnosis codes and weights embedded in the program which doesn't give the user flexibility to define their own sets of codes and weights. This paper illustrates a function design using SAS or R to give user flexibility when calculating the comorbidity index for the following specifications:
• definition of the medical condition using user-defined medical code lists;
• weight assignment for the different medical condition;
• version of the medical coding system used;
• algorithm for calculating the comorbidity index (DEYO, QUAN or any user defined value);
• string matching type when extracting diagnosis codes;
• inclusion or exclusion of specified diagnosis codes.
The designed function can handle the calculation of multiple user defined Comorbidity indexes. |