(169) Exploration of Reason Codes in Real World Cardiovascular System Short-term Disability Claims in the United States

Background: 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.

Objectives: The cardiovascular system had the second most miscoded claims within the major diagnostic categories. We aimed to quantify and identify STD reason codes after the 2016 transition to International Classification of Diseases 10th revision (ICD-10) codes for cardiovascular claims.

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 cardiovascular conditions were compared based on ICD codes. Costs were inflation adjusted using the US consumer price index to December 2023 US dollars. Disability payment calculations used employee-level wage data. Cardiovascular claims were excluded if costs ≤$0, denied, or had missing ICD-codes.

Results: Across all MDCs 12.4% of STD reason codes were miscoded with ICD 9th revision (ICD-9) codes (7.6%), missing codes (3.3%), or Current Procedural Terminology (CPT) / ICD-Procedure Codes (1.5%). Miscoding of reason codes varied across self-insured employers. During the study period, 3343 employees had cardiovascular STD claims for 178,663 days (ICD-9s: 15.2%, 47 [Standard Deviation 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; total cost $278,485; 2,257 total days), Acute Myocardial Infarction (59; $306,453; 2707), Essential Hypertension (48; $171,488; 1,639), Acute but Ill-Defined Cerebrovascular Disease (48; $559, 574; 4222), Other Acute & subacute Forms Ischemic Heart Disease (33; $247,533; 1,649). Most common ICD-10 reasons included: Essential Primary Hypertension (198; $815,874; 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; 3,964). The analysis also identified 313 other ICD-9 codes with $1.5 million total costs and 13,613 total days, and 2358 other ICD-10 codes with $12.1 million total costs and 72,120 total days.

Conclusions: Limiting Short Term Disability analyses between 2016 and 2020 for cardiovascular conditions to ICD-10 reason codes misses 15.2% of claims, understates total STD costs by 14%, and total STD days by 20.3%. Retrospective studies should include comprehensive ICD-9/-10 codes to accurately quantify the burden of conditions.