National fluid shifts: fifteen-year trends in paracentesis and thoracentesis procedures.

PURPOSE: The aim of this study was to evaluate national trends in paracentesis and thoracentesis procedures and the relative roles of specialty groups providing these services.
METHODS: Medicare Physician Supplier Procedure Summary Master Files from 1993 to 2008 were analyzed for paracentesis and thoracentesis procedure codes. Using physician specialty identifier codes, procedure volumes were extracted for radiologists, primary care physicians, and surgeons for both procedures. Volume data were extracted for gastroenterologists and pulmonary and critical care medicine physicians, respectively, for paracentesis and thoracentesis. Frequency by site of service was similarly evaluated. Relative changes were calculated.
RESULTS: Between 1993 and 2008, paracentesis procedures on Medicare fee-for-service beneficiaries increased by 133% (from 64,371 to 149,699), and thoracentesis procedures decreased by 14% (from 147,363 to 127,444). Services by radiologists increased by 964% (from 10,456 to 111,275) and 358% (from 14,531 to 66,602), respectively, while all other targeted groups experienced declines. For paracentesis, radiologist and gastroenterologist procedure shares changed from 16% and 32%, respectively, in 1993 to 74% and 6% in 2008. For thoracentesis, radiologist and pulmonary and critical care medicine physician shares changed from 10% and 49% to 52% and 27%. Relative shifts in site of service to the hospital outpatient setting occurred for both procedures.
CONCLUSIONS: Since 1993, paracentesis procedures on Medicare beneficiaries have more than doubled, while thoracentesis volumes have declined slightly. Radiologists now far exceed gastroenterologists and pulmonary and critical care medicine physicians, respectively, as the predominant providers of these services. Those shifts are likely attributable to both the incremental safety of imaging guidance and also the unfavorable economics of these procedures.