Comparison between the NNT to prevent a COPD exacerbation and the NNT to induce pneumonia properly computed from the corresponding cumulative incidences (CIs) for recent trials of the fluticasone-salmeterol combination inhaler (ICS) versus a long-acting bronchodilator
| COPD exacerbation | Pneumonia | ||||||
|---|---|---|---|---|---|---|---|
| CI at end of study | CI at end of study | ||||||
| Study | Time span for NNT | ICS | No ICS | NNT | ICS | No ICS | NNT |
| TORCH1 | 3 years | 0.922* | 0.945* | 44 | 0.196 | 0.133 | 16 |
| INSPIRE4 | 2 years | 0.578† | 0.590† | 83 | 0.094 | 0.049 | 22 |
| Kardos3 | 44 weeks | 0.47 | 0.55 | 13 | 0.045 | 0.014 | 32 |
| Ferguson5 | 1 year | 0.58 | 0.66 | 13 | 0.07 | 0.04 | 33 |
| Anzueto6 | 1 year | 0.60 | 0.67 | 14 | 0.07 | 0.02 | 20 |
*CI not provided in paper; approximated by converting the incidence rate using the Poisson/exponential distribution. “No ICS” refers to the salmeterol group of the TORCH trial.
†CI not provided in paper; approximated by applying the rate ratio of exacerbations with fluticasone.17
COPD, chronic obstructive pulmonary disease; ICS, inhaled corticosteroid; NNT, number needed to treat.