SEER-Medicare: Comorbidity SAS Macros

SAS Macros to calculate comorbidity weights are provided to assist SEER-Medicare investigators with their analyses. The table below provides an overview of what is included with each macro. NCI recommends use of the 2021 macro. The 2014 and 2000 versions are provided for those needing to reproduce prior results. These macros offer the option of including Medicare hospital (MedPAR) claims only, or also considering physician (NCH) and outpatient claims. The Rule-Out option is recommended in the latter situation. Note that diagnoses using ICD-10 codes, starting in October 2015, are not included in the 2000 and 2014 macros.

NCI does not accept responsibility for the completeness or accuracy of the codes and weights used in the macros. Investigators may modify the macros if they wish to include different diagnosis codes or condition weights.

Comorbidity SAS Macro Diagnosis Codes Rule-Out Option Comorbidity Indices Computed Weights
2021 version ICD-9 and ICD-10 Diagnosis codes identified in the paper by Quan (Procedure and HCPCS codes are not used). Includes conditions (not specific codes) reported twice or more in physician or outpatient claims at least 30 days apart. NCI Comorbidity Index 2021

Weights are the coefficients as shown in the Technical Report.

Weights for cancer-specific sites (breast, lung, prostate, and colorectal cancers) are available in the technical report (PDF, 344 KB) for researchers who want to customize the macro.

Charlson Index 2021 Charlson Index weights (excluding cancer)
2014 version ICD-9 Diagnosis codes identified by professional coders in 2014 (HCPCS codes are not used). Includes codes reported twice or more in physician or outpatient claims at least 30 days apart. NCI Comorbidity Index 2014 Weights are the hazard ratios as shown in the Technical Report for all cancers developed by NCI statisticians in 2014.
Charlson Index 2014 Charlson Index weights (excluding cancer)
2000 version ICD-9 Diagnosis, Procedure, and HCPCS codes identified by Deyo and Romano Includes codes reported twice or more in physician or outpatient claims at least 30 days apart. Charlson Index 2000
  • Prior Charlson comorbidity score
  • Prior+Index Charlson comorbidity score
  • Index Charlson comorbidity score
Charlson Index weights (excluding cancer)
Last Updated: 24 Sep, 2021