Reassessing medicare trends in diagnostic CT colonography after achieving CPT code category I status.

PURPOSE: Compare national trends in utilization and coverage of diagnostic (non-screening) computed tomography colonography (CTC) in the Medicare population before and after achieving Current Procedural Terminology(®) (CPT) Category I code status in 2010.

METHODS: Claims by provider type and location for diagnostic CTC were identified between 2005 and 2013 using Medicare Physician Supplier Procedure Summary Master Files. Frequencies of billed and denied services were used to calculate denial rates for CTC and abdominal computed tomography (CT). PubMed search for articles with "CT colonography" in abstract or title during 1997-2013 was performed. Publications were recorded yearly and matched to CTC denial rates.

RESULTS: Annual Medicare claims for diagnostic CTC increased 212% during 2005-2009 in Category III status and increased 27.4% during 2009-2013 after implementation of Category I codes. Claims for abdominal CT rose 13.4% over the same overall period. Denial rates decreased from 70% to 32.8% between 2005 and 2009, and fluctuated between 24.7 and 30.6% thereafter. Denial rates for abdominal CT remained constant (4.1%-4.6%). From 2005 to 2013, services grew most in the private office (1678-7293) and hospital outpatient (1644-6449) settings with radiologists performing 93.3% of CTC. 1037 CTC publications were identified which increased 3567% between 1997 (3) and 2008 (107), plateaued until 2010 (114) and declined thereafter (75 in 2013).

CONCLUSIONS: Diagnostic CTC grew dramatically from 2005 to 2009, but slowed thereafter; even after achieving CPT Category I code status in 2010. Medicare denial rates declined during early years but later stabilized which paralleled a slowing in new peer-reviewed research. CTC continues to be performed predominately by radiologists in the outpatient setting.