Table 4.
Mixed effects linear regression models for EORTC Quality of Life Questionnaire Head and Neck Module (EORTC-H&N35)
| Subscale (n) | Variable | Estimate | 95% CI | SE | t | p | SDs of Random Effects | |
|---|---|---|---|---|---|---|---|---|
| Intercept | Residual | |||||||
| Pain (n = 109) | Baseline | 36.54 | 32.1 to 40.9 | 2.26 | 16.20 | 17.30 | 14.30 | |
| 1 month | −13.22 | −8.7 to −17.8 | 2.32 | −5.70 | <.001* | |||
| 6 month | −15.73 | −11.0 to −21.0 | 2.40 | −6.55 | <.001* | |||
| 1 year | −16.07 | −11.0 to −20.4 | 2.55 | −6.29 | <.001* | |||
| Swallowing (n = 109) | Baseline | 11.63 | 6.1 to 17.2 | 2.86 | 4.07 | 12.58 | 16.70 | |
| Sx-RT | +6.81 | −1.0 to +14.7 | 4.00 | 1.70 | .092 | |||
| Sx-CRT | +10.36 | +3.1 to +17.7 | 3.70 | 2.80 | .006 | |||
| 1 month | +10.12 | +4.9 to +15.4 | 2.66 | 3.80 | <.001* | |||
| 6 month | +5.46 | 0 to +10.8 | 2.76 | 1.98 | .049 | |||
| 1 year | +1.06 | −4.7 to +6.9 | 2.93 | .36 | .719 | |||
| Senses (n = 109) | Baseline | 16.12 | 11.4 to 20.9 | 2.39 | 6.73 | 17.99 | 15.54 | |
| 1 month | +1.57 | −3.4 to +6.6 | 2.51 | .63 | .533 | |||
| 6 month | +8.92 | +3.8 to +14.2 | 2.60 | 3.43 | <.001* | |||
| 1 year | +2.24 | −3.1 to +7.8 | 2.77 | .81 | .419 | |||
| Speech (n = 108) | Baseline | 19.93 | 15.9 to 24.1 | 2.09 | 9.53 | 12.96 | 15.73 | |
| 1 month | +3.64 | −1.4 to +8.6 | 2.51 | 1.45 | .149 | |||
| 6 month | +2.78 | −2.5 to +7.7 | 2.62 | 1.04 | .302 | |||
| 1 year | −.68 | −6.1 to +4.8 | 2.77 | −.25 | .806 | |||
| Eating (n = 108) | Baseline | 20.50 | 13.2 to 27.8 | 3.69 | 5.55 | 15.78 | 21.84 | |
| Sx-RT | +8.76 | −1.2 to +18.8 | 5.13 | 1.71 | .091 | |||
| Sx-CRT | +14.25 | +5.0 to 23.3 | 4.74 | 3.01 | .003* | |||
| 1 month | +2.19 | −4.6 to +9.1 | 3.47 | .63 | .528 | |||
| 6 month | +3.12 | −4.0 to +10.3 | 3.63 | .86 | .392 | |||
| 1 year | −2.95 | −10.3 to +4.6 | 3.85 | −.77 | .445 | |||
| Social Contact (n = 108) | Baseline | 10.47 | 6.7 to 14.4 | 1.96 | 5.33 | 13.09 | 14.06 | |
| 1 month | +4.26 | −.2 to +8.8 | 2.26 | 1.89 | .060 | |||
| 6 month | +3.97 | −.6 to +8.5 | 2.35 | 1.69 | .092 | |||
| 1 year | +3.94 | −.8 to +8.8 | 2.49 | 1.59 | .114 | |||
| Sexuality (n = 105) | Baseline | 26.11 | 19.5 to 32.9 | 3.40 | 7.68 | 22.52 | 23.45 | |
| 1 month | +1.71 | −6.1 to +9.5 | 3.93 | .44 | .664 | |||
| 6 month | +.51 | −7.6 to +8.4 | 4.07 | .13 | .901 | |||
| 1 year | −7.38 | −15.9 to +1.3 | 4.30 | −1.71 | .088 | |||
| Teeth (n = 109) | Baseline | 23.38 | 17.2 to 29.6 | 3.20 | 7.30 | 16.92 | 26.13 | |
| 1 month | −3.39 | −11.5 to +4.9 | 4.19 | −.81 | .419 | |||
| 6 month | −1.96 | −10.3 to +6.5 | 4.30 | −.46 | .649 | |||
| 1 year | +.24 | −8.8 to +9.3 | 4.64 | .05 | .958 | |||
| Open Mouth (n = 109) | Baseline | 14.65 | 7.4 to 21.9 | 3.71 | 3.94 | 14.56 | 23.62 | |
| Sx-RT | +2.24 | −7.6 to +12.0 | 5.05 | .44 | .659 | |||
| Sx-CRT | +14.59 | +5.5 to +23.7 | 4.68 | 3.12 | .002* | |||
| 1 month | +12.42 | +5.2 to +19.6 | 3.71 | 3.35 | <.001* | |||
| 6 month | +11.30 | +3.7 to +18.9 | 3.88 | 2.92 | .004 | |||
| 1 year | +2.86 | −5.3 to +11.0 | 4.13 | .69 | .490 | |||
| Dry Mouth (n = 109) | Baseline | 28.91 | 19.2 to 38.5 | 4.93 | 5.86 | 18.26 | 24.89 | |
| Sx-RT | −15.39 | −31.2 to +.6 | 8.05 | −1.91 | .057 | |||
| Sx-CRT | −6.05 | −20.4 to +8.4 | 7.32 | −.83 | .409 | |||
| 1 m x Sx | +8.23 | −4.0 to +20.1 | 6.13 | 1.34 | .180 | |||
| 6 m x Sx | +5.08 | −7.4 to +17.5 | 6.39 | .80 | .428 | |||
| 1y x Sx | +6.16 | −7.1 to +20.0 | 6.87 | .90 | .371 | |||
| 1 m x Sx-RT | +3.83 | −15.5 to +23.7 | 10.11 | .38 | .705 | |||
| 6 m x Sx-RT | +42.18 | +22.5 to +62.9 | 10.18 | 4.14 | <.001* | |||
| 1y x Sx-RT | +35.27 | +13.7 to +56.9 | 10.96 | 3.22 | .001* | |||
| 1 m x Sx-CRT | +14.88 | −3.0 to +32.5 | 9.12 | 1.63 | .104 | |||
| 6 m x Sx-CRT | +36.45 | +17.8 to +55.0 | 9.63 | 3.79 | <.001* | |||
| 1y x Sx-CRT | +33.03 | +13.0 to +52.6 | 10.18 | 3.25 | .001* | |||
| Sticky Saliva (n = 109) | Baseline | 25.74 | 19.3 to 32.3 | 3.34 | 7.72 | 18.80 | 26.18 | |
| 1 month | +7.69 | −.7 to +15.8 | 4.17 | 1.85 | .066 | |||
| 6 month | +15.30 | +6.7 to +23.9 | 4.35 | 3.53 | <.001* | |||
| 1 year | +15.34 | +6.2 to +24.5 | 4.63 | 3.33 | .001* | |||
| Cough (n = 109) | Baseline | 17.74 | 13.4 to 22.0 | 2.20 | 8.05 | 12.20 | 17.56 | |
| 1 month | +3.82 | −1.4 to +9.2 | 2.78 | 1.38 | .170 | |||
| 6 month | +6.28 | +.5 to +12.0 | 2.90 | 2.16 | .032 | |||
| 1 year | −3.08 | −9.2 to +3.00 | 3.08 | −1.00 | .318 | |||
Note. *p < .0028; Models with treatment, time, and treatment x time interaction: Baseline = pre-operative mean estimate for surgery only group; Sx-RT/Sx-CRT = difference between pre-operative mean scores and baseline for surgery and radiotherapy, and, surgery and chemoradiotherapy groups, respectively; 1 m/6 m/1y x Sx/Sx-RT/Sx-CRT = difference between mean subscale scores and baseline at 1 month, 6 months, and 1 year post-operation, respectively, for the surgery only, surgery and radiotherapy, and, surgery and chemoradiotherapy groups, respectively; Models with treatment and time (no interaction term): Baseline = pre-operative mean estimate for surgery only group; Sx-RT,/Sx-CRT = difference between pre-operative mean scores and baseline for surgery and radiotherapy, and, surgery and chemoradiotherapy groups, respectively; 1 month/6 months/1 year = difference between mean subscale scores and baseline for respective assessment time point for combined cohort; Models with time variable only: Baseline = pre-operative mean estimate for subscale scores for combined cohort; 1 month/6 months/1 year = difference between mean subscale scores and baseline for respective assessment time point for combined cohort; p-value for baseline scores not provided given that it tests the hypothesis that the baseline mean is significantly different from 0, results of which are not clinically meaningful; 95% CI calculated using bootstrapping approach