Summary of carbon footprint data
| Usual care (n=1155) | FF/VI (n=1081) | |
| Maintenance and rescue inhalers | ||
| n | 1155 | 1081 |
| Total CO2e* over the 12-month treatment period | 351 870 | 175 470 |
| LS geometric mean CO2e per patient (95% CI) | 240 (229 to 252) | 108 (102 to 114) |
| Ratio of LS geometric means† (95% CI) | 2.23 (2.08 to 2.39) | |
| P value | <0.001 | |
| Maintenance only | ||
| n | 1095 | 1081 |
| Total CO2e* over the 12-month treatment period | 165 894 | 27 119 |
| LS geometric mean CO2e per patient (95% CI) | 118 (112 to 125) | 11 (10 to 12) |
| Ratio of LS geometric means† (95% CI) | 10.65 (9.86 to 11.50) | |
| P value | <0.001 | |
| Rescue only | ||
| n | 1131 | 1061 |
| Total CO2e* over the 12-month treatment period | 185 975 | 148 351 |
| LS geometric mean CO2e per patient (95% CI) | 109 (103 to 116) | 88 (82 to 93) |
| Ratio of LS geometric means† (95% CI) | 1.25 (1.15 to 1.35) | |
| P value | <0.001 | |
*For each subject, the total CO2e of each inhaler was calculated as the following: (number of inhalers prescribed) × (CO2e per inhaler), where the CO2e per inhaler is adjusted for the number of actuations in each inhaler. This emission was adjusted, taking the subjects’ time on study medication into account, so it corresponded to 12 months on treatment. Inhalers’ total actuations are adjusted by the inhaler category they were assigned to (see table 1).
†Usual care vs FF/VI.
CO2e, carbon dioxide equivalent; FF/VI, fluticasone furoate/vilanterol; LS, least squares.