Table 2.
Subgroup analysis of the correlation of PNI and OS according to possible confounding factors.
| Subgroup | Number of studies | Number of patients | Pooled HR with 95% CI | p value | Heterogeneity | |
|---|---|---|---|---|---|---|
| I2 (%) | p value | |||||
| Total | 13 | 5891 | 1.93 (1.62–2.30) | < 0.001 | 41.6 | 0.041 |
| Tumor location | ||||||
| Nasopharynx | 6 | 4345 | 1.85 (1.54–2.33) | < 0.001 | 0.0 | 0.536 |
| Oral cavity | 2 | 1728 | 1.77 (1.13–2.76) | 0.013 | 71.6 | 0.030 |
| Hypopharynx | 2 | 182 | 3.45 (1.85–6.43) | < 0.001 | 0.0 | 0.402 |
| Larynx | 2 | 1036 | 2.06 (0.62–6.87) | 0.238 | 38.7 | 0.202 |
| Head and neck | 1 | 145 | 2.95 (1.57–5.54) | < 0.001 | 0 | 0.928 |
| Treatment | ||||||
| OP + adjuvants | 3 | 1157 | 2.18 (1.06–4.48) | 0.035 | 68.3 | 0.043 |
| RT or CCRT | 5 | 3754 | 1.85 (1.49–2.29) | < 0.001 | 11.6 | 0.341 |
| CCRT | 3 | 1044 | 2.60 (1.70–3.97) | < 0.001 | 0.0 | 0.957 |
| Others | 2 | 1728 | 1.77 (1.13–2.76) | 0.013 | 71.6 | 0.030 |
| Sample size | ||||||
| ≤ 500 | 8 | 1683 | 2.44 (2.00–2.96) | < 0.001 | 0 | 0.931 |
| > 500 | 5 | 4208 | 1.43 (1.24–1.65) | < 0.001 | 0 | 0.611 |
| Cut-off value for PNI | ||||||
| ≤ 50 | 8 | 3024 | 2.05 (1.55–2.72) | < 0.001 | 39.6 | 0.094 |
| > 50 | 5 | 2867 | 1.89 (1.48–2.41) | < 0.001 | 52.4 | 0.062 |
| Analysis method | ||||||
| Multivariate analysis | 11 | 5273 | 1.94 (1.61–2.34) | < 0.001 | 48.7 | 0.021 |
| Univariate analysis | 2 | 618 | 2.10 (1.00–4.39) | 0.050 | 0.0 | 0.834 |
OS, overall survival; PNI, Prognostic nutrition index; N status = lymphatic stage; OP, operation; RT, radiotherapy; CCRT, concurrent chemo-radiotherapy.