TABLE 1.
Descriptive statistics of the study samples
| Commercial | Medicare advantage | |
|---|---|---|
| # of total patient‐quarters | 3 465 582 | 2 707 439 |
| % with same attribution from previous quarter | 93.15% | 93.58% |
| % with observation in subsequent quarter | 84.62% | 84.87% |
| Patient characteristics | ||
| # of unique patients | 532,783 | 409,558 |
| Mean age | 58.61 | 72.74 |
| % Female | 40.49% | 53.67% |
| % Elixhauser category 1 (2 or fewer comorbidities) | 39.06% | 18.16% |
| % Elixhauser category 2 (3 to 5 comorbidities) | 49.38% | 51.92% |
| % Elixhauser category 3 (6 or 8 comorbidities) | 9.36% | 21.54% |
| % Elixhauser category 4 (9 or more comorbidities) | 2.20% | 8.38% |
| % attributed in step 1 | 50.19% | 40.94% |
| % attributed in step 2 | 43.38% | 48.12% |
| % attributed in step 3 | 6.28% | 10.76% |
| % attributed in step 4 | 0.16% | 0.18% |
| Physician characteristics | ||
| # of unique physicians | 107,984 | 78,188 |
| % female | 24.62% | 23.93% |
| % PCP | 80.90% | 83.92% |
| % cardiologist | 3.81% | 4.40% |
| % endocrinologist | 9.35% | 4.43% |
| % other specialist | 5.93% | 7.26% |
| % under 50 | 36.77% | 36.33% |
| % less than 20 years since residency | 40.39% | 41.31% |
| % top 20 US medical school | 11.27% | 12.41% |
| % non‐US medical school | 25.68% | 32.32% |
| % other US medical school | 63.05% | 55.27% |
| PCSA characteristics | ||
| # of unique PCSAs | 5,654 | 4,914 |
| Mean % female residents | 51.03% | 51.21% |
| Mean % black residents | 15.28% | 13.84% |
| Mean % white residents | 73.78% | 75.00% |
| Mean % Hispanic residents | 12.61% | 11.13% |
| Mean % residents older than 65 | 12.85% | 14.54% |
| Mean number of internists per 10 000 residents | 4.14 | 4.62 |
| Mean AHRQ SES index | 53.90 | 53.11 |
| % metro | 87.04% | 87.13% |
| Mean malpractice insurance rank | 29.76 | 28.37 |
| Mean malpractice legal rank | 27.78 | 30.39 |
Authors’ analysis of sample of commercially insured and Medicare Advantage patients‐quarters with a diabetes diagnosis and fibrate prescription from 2007 through the third quarter of 2015. “% with same attribution from previous quarter” excludes the first patient‐quarter observation for a patient in calculating the proportion.