A previously published study indicated that between 1993 and 1999, the overall utilization rate of NDI per thousand Medicare beneficiaries increased 3.8%. The rate had dropped by 3.9% among radiologists but increased 25.2% among nonradiologists. Our purpose was to see if these trends continued during the period from 1999 to 2002.
METHOD AND MATERIALS
We studied the Medicare Part B fee-for-service databases between 1999 and 2002 in all CPT-4 codes in the 70,000 and 90,000 series pertaining to NDI. Total utilization rates per thousand beneficiaries were calculated. We then used the Medicare physician specialty codes to determine the separate rates for radiologists, nonradiologists, and multispecialty groups (where the physician provider specialty could not be determined).
Between 1999 and 2002, the overall utilization rate of NDI per thousand Medicare beneficiaries increased from 3151 to 3602 (+14.3%). Among radiologists the rate increased from 2063 to 2302 (+ 11.6%); among nonradiologists the rate increased from 932 to 1151 (+23.5%). Multispecialty groups saw a rate decrease from 156 to 149 (- 4.5%). As a result of the more rapid growth among nonradiologists, radiologists’ share of the entire NDI market declined from 68.9% in 1999 to 66.7% in 2002. Among nonradiologists, cardiologists were the largest single imaging provider group; their utilization rate rose from 370 in 1999 to 526 in 2002 (+42.2%).
There appears to have been a distinct change in NDI utilization trends in recent years. While the overall utilization rate of NDI had increased by a total of only 3.8% during the years from 1993 to 1999, there was considerable acceleration in more recent years, with the rate increasing 14.3% from 1999 to 2002. Among radiologists, the utilization rate of NDI had dropped almost 4% from 1993 to 1999, but it subsequently rose almost 12% from 1999 to 2002. Nonradiologists’ utilization rate grew approximately twice as rapidly as radiologists’ between 1999 and 2002, probably reflecting the effect of self-referral. Within the nonradiologist category, growth in utilization was especially pronounced among cardiologists, whose rate increased almost 4 times as rapidly as radiologists’.