Table 2:
Comparative cost-effectiveness of treatment approaches with and without rifaximin in irritable bowel syndrome with diarrhea (IBS-D)
| Strategy | Total cost ($/yr) |
Total effectiveness (QALY gained/yr) |
Incremental cost ($/yr) |
Incremental effectiveness (QALY/yr) |
ICER ($/QALY gain) |
|---|---|---|---|---|---|
| Societal perspective with one-year time horizon | |||||
| Non-coverage of rifaximin | $4,355 | 0.747 | |||
| Unrestricted rifaximin access | $7,608 | 0.750 | $3,252 | +0.0029 | $1,138,254 (dominated*) |
| Formulary-restricted rifaximin access | $4,783 | 0.752 | $428 | +0.0052 | $82,375 |
| Societal perspective with five-year time horizon | |||||
| Non-coverage of rifaximin | $4,457 | 0.747 | |||
| Unrestricted rifaximin access | $7,529 | 0.750 | $3,072 | +0.0029 | $1,049,586 (dominated*) |
| Formulary-restricted rifaximin access | $4,744 | 0.752 | $287 | +0.0055 | $51,709 |
| Payer perspective with one-year time horizon | |||||
| Non-coverage of rifaximin | $728 | 0.747 | |||
| Unrestricted rifaximin access | $4,177 | 0.750 | $3,449 | +0.0029 | $1,207,136 (dominated*) |
| Formulary-restricted rifaximin access | $1,622 | 0.752 | $894 | +0.0052 | $171,850 |
| Payer perspective with five-year time horizon | |||||
| Non-coverage of rifaximin | $703 | 0.747 | |||
| Unrestricted rifaximin access | $4,110 | 0.750 | $2,485 | +0.0029 | $1,164,033 (dominated*) |
| Formulary-restricted rifaximin access | $1,625 | 0.752 | $921 | +0.0055 | $166,155 |
*
An unrestricted rifaximin access strategy was dominated (less effective and more expensive) than a formulary-restricted rifaximin strategy at all price points. ICER = incremental cost effectiveness ratio; QALY = quality adjusted life year; TCA = tricyclic antidepressant; IBS-D = irritable bowel syndrome with diarrhea.