Exploration of Reason Codes in Real World Cardiovascular System Short-Term Disability Claims in the United States

OBJECTIVES: Short Term Disability (STD) is used by 5.6% of United States (US) employees that have the benefit, adding an additional 25% of costs to total medical costs for employees that utilize STD, and 6%—7% for the full employee population. The Cardiovascular System (CV) is the second most miscoded claims within the major diagnostic categories. We aimed to quantify and compare CV STD reason codes after the 2016 transition to ICD-10 codes.

METHODS: Retrospective analysis of STD claims from US self-insured employers in Workpartners’ Research and Reference Database (RRDb) between 2016 and 2020. STD claims for CV diagnoses were compared based on ICD-9/-10 codes. Disability payment calculations used employee-level wage data. Claims were excluded if costs ≤$0, denied, or had missing ICD-codes.

RESULTS: Across all MDCs, 12.5% of STD reason codes were miscoded with ICD-9s (8.8%) or ICD-Current Procedural Terminology codes (1.9%). Miscoding of reason codes varied across self-insured employers. During the study period, 3343 employees had CV STD claims for 178,663 days (ICD-9s: 15,2%, 47l [SD 44] mean-days, 26,653 total-days; ICD-10s: 84.8%, 48 [48] mean-days, 151,910 total-days). Most common ICD-9 reasons included: Chest Pain (62 employees/$278,485/2257 days), Acute Myocardial Infarction (59/$306,453/2707), Essential Hypertension (48/$171,488/1639), Acute But Ill-Defined Cerebrovascular Disease (48/$559,574/4222), Other Acute&subacute Forms Ischemic Heart Disease (33/$247,533/1649). Most common ICD-10 reasons included: Essential Primary Hypertension (198/$815,574/7308), Atherosclerotic Heart Disease of Native Coronary Artery W/O Angina Pectoris (174/$1,939,559/9642), Cerebral Infarction-Unspecified (180/$2,606,439/16,091), Chest Pain-Unspecified (142/$499,300/3681), Atherosclerotic Heart Disease Native Coronary Artery (92/$668,153/3964). There were 313 other ICD-9 and 2358 other ICD-10 codes identified.

CONCLUSIONS: Limiting Short Term Disability analyses between 2016 and 2020 for Cardiovascular conditions to ICD-10 reason codes missed 15.2% of claims, understating total STD costs by 12.2%, and total STD days by 14.9%. Retrospective studies should include comprehensive ICD-9/-10 codes to accurately quantify the burden of conditions.