(111) Trends in Diagnostic Coding for Musculoskeletal Conditions: An Evaluation of ICD-10 Use in the Veterans Health Administration

Musculoskeletal disorders (MSD) are the most common diagnoses among Veterans presenting with pain in the Veterans Health Administration (VHA). The implementation of the International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10) sought to increase specification of diagnoses, but studies have yet to evaluate this effect. In this study, we examined the most frequently utilized MSD-related ICD-10 diagnostic codes and describe their association with Veteran characteristics. A cross-sectional analysis of all Veterans assigned an ICD-10 diagnostic “M-code” representing “Diseases of the Musculoskeletal System and Connective Tissue” in 2016 and 2017 was performed. Data were obtained from the VHA Musculoskeletal Disorders (MSD) Cohort, which includes over 5 million Veterans. We examined coding frequency among patient visits (n=31,619,884). A total of 36 of the possible 6,487 ICD-10 M-codes demonstrated a frequency of greater than 0.50% of all visits, accounting for 63.74% of all MSD coded visits. “Low Back Pain” (M54.5) was the most commonly used code (18.32%). The next most common codes were “Cervicalgia” (M54.2, 3.55%), “Pain in Right Knee” (M25.561, 3.09%), “Pain in Left Knee” (M25.562, 2.93%), and “Pain in Right Shoulder” (M25.511, 2.79%). Other codes of interest included “Gout, Unspecified” (M10.9, 1.99%), “Unspecified Osteoarthritis, Unspecified Site” (M19.90, 1.35%), “Rheumatoid Arthritis, Unspecified Site” (M06.9, 0.77%), and “Fibromyalgia” (M79.7, 0.61%). Of the 36 most used codes, 28 (77.78%) were nonspecific diagnoses that do not specify a site of involvement or that describe pain in a general anatomic region. Patient age, gender, race, and pain intensity scores were examined to compare demographic differences in diagnostic coding patterns. Our findings suggest that providers in VHA are selecting musculoskeletal diagnoses from a limited subset of ICD-10 codes. Despite over 6,000 possible M-codes, a small number of codes account for most MSD-related visits, possibly due to homogeneity in Veteran MSD conditions.