Table 2– Association of the sit-to-stand (STS) test with mortality, exacerbations and health-related quality of life (HRQoL)
Mortality
Patients alive at 2 yearsPatients dead at 2 years
STS test number of repetitions in 1 min19.5±8.711.8±6.3
Association of STS with mortalityUnadjusted association (hazard ratio per 1 more repetition)0.86 (95% CI 0.81–0.92), p<0.0001; z= -4.73
Adjusted association (hazard ratio per 1 more repetition)0.90 (95% CI 0.83–0.97), p=0.004; z= -2.84
Adjusted association (hazard ratio per 5 more repetitions)0.58 (95% CI 0.40–0.85) p=0.004; z= -2.84
CovariatesAge 1.08 (se 0.026, z=3.17, p=0.002); FEV1 0.98 (se 0.012, z= -1.76, p=0.078); dyspnoea 1.12 (se 0.185, z=0.69, p=0.49); LABA/ICS 0.56 (se 0.29, z= -1.11, p=0.269)
Exacerbations
Patients with no exacerbation during 2 years of follow-upPatients with ≥1 exacerbation during 2 years of follow-up
STS test number of repetitions in 1 min19.4±8.518.1±8.1
Association of STS test with exacerbationsUnadjusted association (incidence rate ratio per 1 more repetition)0.99 (95% CI 0.97–1.01), p=0.21; z= -1.26
Adjusted association (incidence rate ratio per 1 more repetition)1.00 (95% CI 0.98–1.02), p=0.94; z=0.08
CovariatesAge 1.00 (se 0.007, z= -0.48, p=0.63); FEV1 0.98 (se 0.005, z= -5.02, p<0.001); dyspnoea 1.06 (se 0.067, z=0.89, p=0.38); LABA/ICS 1.52 (se 0.34, z=1.87, p=0.062)
HRQoL from baseline to 2-year follow-up
Association of STS test with CRQ dyspnoeaUnadjusted difference on scale from 1–7 per 1 more repetition0.06 (95% CI 0.04–0.07), p<0.001; z=7.55
Adjusted difference on scale from 1–7 per 1 more repetition0.05 (95% CI 0.04–0.07), p<0.001; z=7.10
Adjusted difference on scale from 1–7 per 5 more repetitions0.26 (95% CI 0.19–0.34), p<0.001; z=7.10
CovariatesAge 0.017 (se 0.007, z=2.54, p=0.011); FEV1 0.026 (se 0.004, z= -6.48, p<0.001); LABA/ICS -0.396 (se 0.16, z=–2.41, p=0.016)
Association of STS test with CRQ fatigueUnadjusted difference on scale from 1–7 per 1 more repetition0.06 (95% CI 0.04–0.07), p<0.001; z=8.57
Adjusted difference on scale from 1–7 per 1 more repetition0.04 (95% CI 0.03–0.05), p<0.001; z=6.06
Adjusted difference on scale from 1–7 per 5 more repetitions0.19 (95% CI 0.13–0.26), p<0.001; z=6.06
CovariatesAge 0.007 (se 0.005, z=1.34, p=0.18); FEV1 -0.007 (se 0.005, z= -2.04, p=0.042); dyspnoea 0.361 (se 0.038, z=9.51, p<0.001); LABA/ICS 0.108 (se 0.13, z=0.81, p=0.42)
Association of STS test with CRQ emotional functionUnadjusted difference on scale from 1–7 per 1 more repetition0.03 (95% CI 0.02–0.05), p<0.001; z=5.33
Adjusted difference on scale from 1–7 per 1 more repetition0.02 (95% CI 0.01–0.03), p=0.001; z=3.24
Adjusted difference on scale from 1–7 per 5 more repetitions0.10 (95% CI 0.04–0.16), p=0.001; z=3.24
CovariatesAge 0.013 (se 0.005, z=2.52, p=0.012); FEV1 -0.009 (se 0.003, z= -2.81, p=0.005); dyspnoea 0.357 (se 0.036, z=9.87, p<0.001); LABA/ICS 0.169 (se 0.13, z=1.32, p=0.19)
Association of STS test with CRQ masteryUnadjusted difference on scale from 1–7 per 1 more repetition0.03 (95% CI 0.02–0.04), p<0.001; z=5.79
Adjusted difference on scale from 1–7 per 1 more repetition0.02 (95% CI 0.00–0.03), p=0.005; z=2.84
Adjusted difference on scale from 1–7 per 5 more repetitions0.08 (95% CI 0.02–0.13), p=0.005; z=2.84
CovariatesAge 0.008 (se 0.005, z=1.69, p=0.09); FEV1 -0.002 (se 0.003, z= -0.65, p=0.51); dyspnoea 0.340 (se 0.033, z=10.41, p<0.001); LABA/ICS -0.053 (se 0.116, z= -0.46, p=0.64)
  • Data are presented as mean±sd, unless otherwise stated. FEV1: forced expiratory volume in 1 s; LABA: long-acting β-agonist; ICS: inhaled corticosteroid; CRQ; Chronic Respiratory Questionnaire. z-values are reported to show the relative strength of association of each variable in the multivariable regression models. All regression coefficients for continuous variables except for handgrip strength are per increase of 1 unit (1 year for age, 1% predicted for FEV1 and 1 point for dyspnoea).