Table 2. Characteristics of Cost-Saving Generic-Generic Therapeutic Substitutionsa.
| Substitution type | No. (%) | Mean (SD), No. | P value | |||
|---|---|---|---|---|---|---|
| Drug pairs | Claims | Therapeutic alternatives | Manufacturers of the high-cost generic | Manufacturers of the therapeutic alternative | ||
| Same drug | ||||||
| Different manufacturer | 2 (4.4) | 3090 (11.1) | 1.0 (0.0) | 15.0 (0.0) | 15.0 (0.0) | NA |
| Different strength | 11 (24.4) | 9891 (35.5) | 1.0 (0.0) | 4.8 (3.1) | 8.2 (5.3) | .10 |
| Different dosage form | 17 (37.8) | 7345 (26.3) | 1.1 (0.3) | 7.9 (4.5) | 15.2 (7.9) | <.001 |
| Different drug, same therapeutic class | 15 (33.3) | 7553 (27.1) | 2.2 (1.1) | 6.0 (5.7) | 11.4 (3.5) | .003 |
| Overall | 45 (100) | 27 879 (100) | 1.4 (0.9) | 6.8 (5.0) [95% CI, 5.2-8.4] | 12.3 (6.4) [95% CI, 10.3-14.3] | <.001 |
Abbreviation: NA, not applicable.
a
Source: Authors' analysis of the top 1000 generic drugs in the Colorado All Payer Claims Database. Number of manufacturers was obtained from the Food and Drug Administration's Orange Book and National Drug Code Directory.11,12 A total of 45 drug pairs representing 45 high-cost generics and 64 therapeutic alternatives were examined. P values were obtained using 2-tailed paired t tests.