Parameter estimates for the course of decline of per cent predicted forced vital capacity from time of initiation of noninvasive ventilation (Model 2)
| Parameter | Overall cohort | Adherent patients | Nonadherent patients | p-value# | |||
| Mean (se)¶ | 95% CI | Mean (se)¶ | 95% CI | Mean (se)¶ | 95% CI | ||
| b1 % | 74.0 (1.2) | 71.1, 76.4 | 72.2 (1.5) | 69.3, 75.1 | 76.1 (1.6) | 72.8, 79.3 | 0.081 |
| b2 % | −33.4 (1.7) | −36.7, −30.1 | −30.3 (1.9) | −34.1, −26.5 | −35.8 (2.5) | −40.8, 30.7 | 0.091 |
| b3 months | −5.2 (0.5) | −6.2, −4.3 | −4.3 (0.5) | −5.3, 3.3 | −6.7 (0.9) | −8.4, −5.0 | 0.017 |
| b4 months | 3.1 (0.4) | 2.4, 3.9 | 2.3 (0.4) | 1.4, 3.1 | 3.8 (0.6) | 2.6, 5.0 | 0.036 |
| b1+b2 % | 40.6 (2.1) | 34.7, 43.0 | 41.9 (1.1) | 39.7, 44.1 | 38.5 (2.1) | 34.4, 42.7 | 0.16 |
b1: per cent predicted vital capacity before onset of decline of lung function; b2: magnitude of decline in predicted forced vital capacity to the lower asymptote, represented in the model as a negative number such that b1+b2 is the final per cent predicted vital capacity; b3: time (months) from initiation of noninvasive ventilation to the midpoint between the two asymptotes, also representing the inflection point of the forced vital capacity time-course curve (a negative number as the inflection occurred before initiation of noninvasive ventilation); b4: a timescale factor (months) that reflects the rapidity of decline of forced vital capacity, such that a smaller b4 reflects a more rapid decline.
#: difference between adherent and nonadherent patients; significance set at p<0.05.
¶: p<0.001 for all parameter estimates, indicating that all four parameters contributed significantly to the per cent predicted forced vital capacity.