Table 2 Result of the multiple beta-binomial mixed-effects model adjusted by time-dependent covariates for the Symptoms component of the SGRQ questionnaire over time
From: Predictive factors over time of health-related quality of life in COPD patients
SGRQ |  |  | β | SD(β) | P | OR | 95%CI |
|---|---|---|---|---|---|---|---|
Symptoms | Intercept |  | 2.79 | 0.269 | < 0.001 | – | – |
Time | (year) | − 0.005 | 0.010 | 0.341 | 0.991 | (0.971–1.010) | |
Age | (5 years) | −0.138 | 0.013 | < 0.001 | 0.871 | (0.850–0.893) | |
FEV1 | (100 ml) | −0.027 | 0.005 | < 0.001 | 0.973 | (0.964–0.983) | |
RV% | (9%) | 0.010 | 0.004 | 0.008 | 1.010 | (1.003–1.017) | |
DLCO% | (11%) | −0.020 | 0.009 | 0.028 | 0.981 | (0.964–0.998) | |
Handgrip | (5 kg) | −0.041 | 0.011 | 0.001 | 0.960 | (0.939–0.981) | |
6mWT | (25 m) | − 0.032 | 0.005 | < 0.001 | 0.968 | (0.958–0.978) | |
PA | None/Any | – | – | – | – | – | |
Work/intense | −0.198 | 0.044 | < 0.001 | 0.820 | (0.753–0.893) | ||
Previous hospitalizations | 0 | – | – | – | – | – | |
1 | 0.197 | 0.050 | < 0.001 | 1.217 | (1.105–1.342) | ||
2 | 0.284 | 0.074 | < 0.001 | 1.328 | (1.148–1.537) | ||
>  2 | 0.203 | 0.068 | 0.003 | 1.224 | (1.073–1.398) | ||
Sigmaa |  | 0.742 | 0.024 | – | – | – |