A total of 645 patients were included in this study. The optimal cut-off value of GNRI was determined to be 98. Based on this value, patients were divided into two groups: 87 patients in the low GNRI group (≤ 98) and 558 patients in the high GNRI group (> 98). The patients included 413 males (64.0%) and 232 females (36.0%), with 485 young patients (≤ 65) (75.2%) and 160 elderly patients (> 65) (24.8%). There were 627 early (pT1-T2) ccRCC patients (97.2%) and 18 late (pT3-T4) patients(2.8%). According to the Fuhrman system, there were 494 low-grade (Fuhrman I-II) ccRCC patients (76.6%), and 151 high-grade (Fuhrman III-IV) patients (23.4%). The comparison of clinicopathological characteristics of patients between the two groups is presented in Table 1. The GNRI was significantly associated with age (χ2 = 14.808, P < 0.001), Fuhrman grade (χ2 = 10.027, P = 0.002), albumin (t = 20.650, 95% CI: 8.053-9.745, P < 0.001), and total cholesterol (t = 7.193, 95% CI: 22.372-39.173, P < 0.001). There were no significant differences in sex, history of hypertension, history of diabetes, smoking history, BMI, tumor sidedness, pT stage, surgical method, surgical approach, and tumor size between the two groups. After PSM, 268 patients were included, with 78 patients in the low GNRI group and 190 patients in the high GNRI group. There were no significant differences in the clinicopathological characteristics between the two groups (Table 1).

As for OS, the median follow-up time was 37 months (range: 1-112 months). At the last follow-up, a total of 45 patients had died. Kaplan-Meier analysis showed that OS was significantly worse in the low GNRI group than in the high GNRI group (5-year OS: 83.9% VS 94.8%, P < 0.001) (Fig. 2a). Univariate analysis indicated that sex, age, history of diabetes, smoking history, pT stage, Fuhrman grade, surgical method, surgical approach, tumor size and GNRI significantly influenced OS. Multivariate analysis showed that age (HR: 0.427, 95% CI: 0.232-0.784, P = 0.006), diabetes history (HR: 0.326, 95% CI: 0.158-0.670, P = 0.002), smoking history (HR: 0.273, 95% CI: 0.150-0.498, P < 0.001), tumor size (HR: 1.494, 95% CI: 1.351-1.652, P < 0.001) and GNRI (HR: 2.686, 95% CI: 1.403-5.145, P = 0.003) were independent prognostic factors for OS (Table 2).

Kaplan-Meier survival curves in patients with non-metastatic ccRCC before and after propensity score matching. a, d overal survival (OS), b, e cancer-specific survival (CSS), and c, f recurrence-free survival (RFS). GNRI, geriatric nutritional risk index

After PSM, Kaplan-Meier analysis showed that the low GNRI group still had worse OS compared with the high GNRI group (5-year OS: 85.9% VS 93.7%, P < 0.05) (Fig. 2d). Univariate analysis indicated that smoking history, pT stage, Fuhrman grade, tumor size and GNRI were significantly correlated with OS. Multivariate analysis showed that smoking history (HR: 0.386; 95% CI: 0.175-0.855, P = 0.019), tumor size (HR: 1.569; 95% CI: 1.263-1.948, P < 0.001) and GNRI (HR: 3.234; 95% CI: 1.360-7.692, P = 0.008) were independent prognostic factors for OS (Table 2).

As for CSS, the median follow-up time was 37 months (range: 1-112 months). At the last follow-up, 33 patients had died from RCC. Kaplan-Meier analysis showed that the CSS was significantly worse in the low GNRI group than in the high GNRI group (5-year CSS: 87.4% VS 96.2% P < 0.001) (Fig. 2b). Univariate analysis indicated that history of diabetes, smoking history, pT stage, Fuhrman grade, surgical method, surgical approach, tumor size and GNRI significantly influenced CSS. Multivariate analysis showed that history of diabetes (HR: 0.241; 95% CI: 0.109-0.533, P < 0.001), smoking history (HR: 0.420; 95% CI: 0.210-0.838, P = 0.014), tumor size (HR: 1.449; 95% CI: 1.287-1.630, P < 0.001) and GNRI (HR: 2.987; 95% CI: 1.411-6.324, P = 0.004) were independent prognostic factors for CSS (Table 3).

After PSM, Kaplan-Meier analysis showed that the low GNRI group still had worse CSS compared with the high GNRI group (5-year CSS: 87.2% VS 95.8%, P < 0.05) (Fig. 2e). Univariate analysis indicated that pT stage, Fuhrman grade, tumor size and GNRI were significantly correlated with CSS. Multivariate analysis showed that tumor size (HR: 1.348; 95% CI: 1.128-1.610, P = 0.001) and GNRI (HR: 4.440; 95% CI: 1.638-12.033, P = 0.003) were independent prognostic factors for CSS (Table 3).

As for RFS, the median follow-up time was 35 months (range: 1-112 months). At the last follow-up, 51 patients had recurrence or metastasis. Kaplan-Meier analysis showed that the RFS was significantly worse in the low GNRI group than in the high GNRI group (5-year RFS: 83.9 VS 93.7% P < 0.001) (Fig. 2c). Univariate analysis indicated that smoking history, pT stage, Fuhrman grade, surgical method, surgical approach, tumor size and GNRI significantly influenced RFS. Multivariate analysis showed that smoking history (HR: 0.473; 95% CI: 0.270-0.830, P = 0.009), tumor size (HR: 1.373; 95% CI: 1.255-1.503, P < 0.001) and GNRI (HR: 2.731; 95% CI: 1.455-5.129, P = 0.002) were independent prognostic factors for RFS (Table 4).

After PSM, Kaplan-Meier analysis showed that the low GNRI group still had worse RFS compared with the high GNRI group (5-year RFS: 85.9% VS 93.2% P < 0.05) (Fig. 2f). Univariate analysis indicated that pT stage, Fuhrman grade, tumor size and GNRI were significantly correlated with RFS. Multivariate analysis showed that tumor size (HR: 1.376; 95% CI: 1.171-1.618, P < 0.001) and GNRI (HR: 3.433; 95% CI: 1.453-8.113, P = 0.005) were independent prognostic factors for RFS (Table 4).

To verify the robustness and consistency of our results, we performed subgroup analysis based on age (≤ 65 / > 65), early (pT1-T2) and low-grade (Fuhrman I-II) ccRCC. The subgroup analysis based on age showed that among young patients (≤ 65), OS (P = 0.001), CSS (P = 0.013) and RFS (P = 0.002) in the high GNRI group were significantly better than those in the low GNRI group (Fig. 3a-c). Similarly, among elderly patients (> 65), OS (P = 0.016), CSS (P = 0.006) and RFS (P = 0.048) in the high GNRI group were significantly better than those in the low GNRI group (Fig. 3d-f). In the early (pT1-T2) ccRCC subgroup, patients in the high GNRI group had higher OS (P < 0.001), CSS (P < 0.001) and RFS (P < 0.001) compared to those in the low GNRI group (Fig. 4a-c). In the low-grade (Fuhrman I-II) ccRCC subgroup, patients with high GNRI also had better OS (P < 0.001), CSS (P < 0.001) and RFS (P = 0.044) compared with patients with low GNRI (Fig. 5a-c).

Kaplan-Meier survival curves in patients with non-metastatic ccRCC in the young subgroup; Kaplan-Meier curves for OS(d) , CSS(e) and RFS(f) of patients with non-metastatic ccRCC in the elderly subgroup. a, d overal survival (OS), b, e cancer-specific survival (CSS), and c, f recurrence-free survival (RFS). GNRI, geriatric nutritional risk index

Kaplan-Meier survival curves in patients with pT1-T2 non-metastatic ccRCC. a overal survival (OS), b cancer-specific survival (CSS), and c recurrence-free survival (RFS). GNRI, geriatric nutritional risk index

Kaplan-Meier survival curves in patients with Fuhrman grades I-II non-metastatic ccRCC. a overal survival (OS), b cancer-specific survival (CSS), and c recurrence-free survival (RFS). GNRI, geriatric nutritional risk index