Table 3.
Event Counts for Predictors
| Predictors | Days Meeting Criteria | Events Detected | Event Rate/Year | |
|---|---|---|---|---|
| O<90%* | = Exacerbation from SpO2 < 90% | 173 | 26 | 3.63 |
| O-4%* | = Exacerbation from SpO2 < (7-day average-4%) | 6 | 6 | 0.84 |
| FEV1* | = Exacerbation from FEV1 < (7-day average-1.645*SD) | 18 | 15 | 2.09 |
| FVC* | = Exacerbation from FVC < (7-day average-1.645*SD) | 15 | 13 | 1.81 |
| PEF* | = Exacerbation from PEF < (7-day average-1.645*SD) | 23 | 16 | 2.23 |
| IC* | = Exacerbation from IC < (7-day average-1.645*SD) | 17 | 16 | 2.23 |
| Inactiveǂ | = Physically inactive for 2 or more days | 47 | 18 | 2.51 |
| MRx# | = Loss of maintenance Rx for 2 consecutive days | 13 | 2 | 0.28 |
| QuickBD | = Increased use of quick-acting BD more than 2 times above first 7 day average | 117 | 52 | 7.25 |
Notes: *Each predictor was counted as positive on a particular day if its value met pre-specified criteria for 2 or more consecutive days. An event was considered to have been detected if the pre-specified criteria then returned to baseline. The event rate was based on 7.17 patient-years of monitoring. ǂPhysically inactive was counted if subjects reported no physical activity on the daily questionnaire. #Loss of maintenance treatment was defined by the daily treatment questionnaire.
Abbreviations: SpO2, oxygen saturation; FEV1, forced expiratory volume in one second; FVC, forced vital capacity; PEF, peak expiratory flow; IC, inspiratory capacity.