For this story, ProPublica analyzed provider billing patterns for routine office visits in Medicare. We focused on those for established patients who had been seen at least one time by the provider previously. These are among the most common services performed in the program.
We used data released in April by the Centers for Medicare and Medicaid Services showing the services provided by and payments made to providers in Medicare's Part B program in 2012. The data does not include information on services provided to patients in Medicare Advantage health plans. Medicare redacted data on services when a provider billed for a service for fewer than 11 patients.
More than 440,000 providers billed the program for routine office visits for at least 11 patients in 2012.
Office visits are coded using the Current Procedural Terminology system devised by the American Medical Association and used by Medicare. The severity of each visit depends on three criteria: the thoroughness of the review of a patient's medical history, the comprehensiveness of the physical exam, and the complexity of medical decision-making involved.
An uncomplicated visit, typically of short duration, should be coded a "1"; a visit that involves more intense examination and often consumes more time should be coded a "5." The most common code for visits is in the middle, a "3."
To protect against variation hidden by redactions, we focused on the 329,500 providers who billed for at least 100 routine visits in 2012.
We identified more than 1,200 providers who billed for every office visit using the 99215 code. We found another 600 providers who billed level 5 visits at least 90 percent of the time. All told, we identified about 20,000 providers (including those noted above) who billed exclusively using level 4 and 5 codes.
Some were senior doctors at prominent teaching hospitals that may take on only complex cases; most were not.
Finally, we looked for other patterns, such as providers who charged for level 5 visits to an unusually large percentage of their patients relative to other doctors in their specialties, or those who gave each patient multiple level 5 visits. One Arizona optometrist, for instance, billed for more level 5 visits than all of his peers in the state combined.
We did not analyze the distribution of billing codes for other types of visits and procedures that are more common for certain specialties, such as those for eye doctors, emergency room doctors and psychiatrists.