| Age < 70 vs. ≥70 | 0.61 | 0.42–0.88 | 0.0083 | 0.64 | 0.43–0.95 | 0.026 |
| Gender Male vs. Female | 1.99 | 1.07–3.69 | 0.029 | 2.47 | 1.27–4.81 | 0.0080 |
| ECOG Performance status 0–1 vs.2–3 | 0.31 | 0.17–0.55 | < 0.001 | 0.94 | 0.461.93 | 0.87 |
| BMI < 20 vs. ≥20 | 1.72 | 1.20–2.50 | 0.0043 | 1.53 | 1.03–2.28 | 0.035 |
| Primary site Oropharynx vs. others | 1.25 | 0.85–1.83 | 0.25 | | | |
| T-classification 1–2 vs. 3–4 | 0.42 | 0.28–0.61 | < 0.001 | 0.58 | 0.38–0.87 | 0.0087 |
| N-classification 0-2b vs. 2c-3 | 0.50 | 0.34–0.74 | < 0.001 | 0.55 | 0.37–0.84 | 0.0050 |
| Histology SCC vs. others | 2.06 | 0.84–5.06 | 0.11 | | | |
| Brinkman index < 500 vs. ≥500 | 0.95 | 0.66–1.36 | 0.76 | | | |
| Habitual alcoholic consumption Yes vs. No | 1.22 | 0.85–1.72 | 0.29 | | | |
| Use of ACEi or ARB Yes vs. No | 0.97 | 0.63–1.49 | 0.88 | | | |
| Use of PPI or H2 blocker Yes vs. No | 1.20 | 0.85–1.72 | 0.30 | | | |
| Oral hygiene before treatment Good vs. Poor | 0.66 | 0.46–0.94 | 0.021 | 0.94 | 0.65–1.37 | 0.76 |
| Coexistence of other malignancies Yes vs. No | 1.16 | 0.90–1.52 | 0.24 | | | |
| Charlson comorbidity index 0–1 vs. ≥2 | 0.62 | 0.41–0.92 | 0.018 | 0.72 | 0.47–1.11 | 0.14 |
| Serum albumin before treatment Within normal limits vs. less than normal range | 0.33 | 0.22–0.48 | < 0.001 | 0.50 | 0.30–0.83 | 0.0069 |
| Hemoglobin before treatment Within normal limits vs. less than normal range | 0.58 | 0.40–0.83 | 0.0028 | 0.83 | 0.53–1.31 | 0.43 |
| Use of sleeping pills before treatment Yes .vs No | 2.00 | 1.39–2.86 | < 0.001 | 1.16 | 0.73–1.85 | 0.54 |
| Induction chemotherapy Yes vs. No | 0.87 | 0.56–1.33 | 0.51 | | | |
| Concurrent chemotherapy regimen CDDP vs. others | 0.66 | 0.45–0.97 | 0.036 | 0.71 | 0.45–1.12 | 0.14 |
| Radiation technique Conventional 3D-CRT vs. IMRT | 1.26 | 0.83–1.92 | 0.27 | | | |
| Radiation dose 70Gy vs. <70Gy | 0.25 | 0.12–0.50 | < 0.001 | 0.18 | 0.084–0.40 | < 0.001 |
| Irradiation field Local vs. whole neck | 0.90 | 0.56–1.43 | 0.66 | | | |
| Percutaneous endoscopic gastrostomy prior to treatment Yes vs. No | 1.76 | 1.21–2.56 | 0.0034 | 1.16 | 0.78–1.73 | 0.47 |
| Treatment Inpatient vs. Outpatient | 1.77 | 1.24–2.53 | 0.0018 | 1.47 | 0.99–2.17 | 0.052 |
| The worst mucositis grade during treatment 1–2 vs. 3–4 | 0.98 | 0.68–1.40 | 0.90 | | | |
| The worst dysphagia score during treatment 1–2 vs. 3–4 | 0.92 | 0.64–1.31 | 0.63 | | | |
| Aspiration pneumonia during treatment Yes vs. No | 1.56 | 2.22–3.23 | < 0.001 | 1.58 | 1.06–2.35 | 0.024 |
