TABLE 1.
Basic characteristics of studies included.
| Study (Year) | Country | Study type | Multicenter | NOS scores | Tumor stage | Treatment comparison | Follow-up (months) | Male patients (%) | Age | Survival analysis | Measure of outcomes |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Rieken et al. (2013) | United States | Cohort study | Y | 7 | NMIBC | Metformin vs non-metformin | 64 | 76.50% | 65.0 (mean) | OS, RFS, PFS | HR |
| Mamtani et al. (2014) | United Kingdom | Cohort study | Y | 8 | NR | Metformin vs sulfonylurea (SU) | 24 | 55.67% | 62.0 in metformin, 69.0 in SU (median) | Incidence of bladder cancer | / |
| Tseng (2014) | Taiwan, China | Cohort study | Y | 8 | NR | Metformin vs non-metformin | NR | 49.00% | NR | Incidence of bladder cancer | / |
| Rieken et al. (2014) | United States | Cohort study | Y | 7 | NMIBC + MIBC | Metformin vs non-metformin | 34 | 78.40% | 66.0 (median) | OS, RFS, DSS | HR |
| Tsilidis et al. (2014) | United Kingdom | Cohort study | Y | 8 | NR | Metformin vs sulfonylurea (SU) | 61 | 56.59% | NR | Incidence of bladder cancer | / |
| Chen et al. (2015) | Taiwan, China | Cohort study | Y | 8 | NMIBC | Metformin vs sulfonylurea (SU) | 30 | 53.80% | 60.6 in metformin, 62.4 in SU (median) | Incidence of bladder cancer | / |
| Nayan et al. (2015) | Canada | Cohort study | N | 7 | NMIBC + MIBC | Metformin vs non-metformin | 50 | 81.00% | 71.0 (mean) | OS, RFS, DSS | HR |
| Richard (2018) | Canada | Cohort study | N | 8 | NMIBC | Metformin vs non-metformin | 62.4 | 79.00% | 78.0 (median) | OS, DSS | HR |
| Goossens et al. (2015) | United Kingdom | Cohort study | Y | 8 | NR | Metformin vs sulfonylurea (SU) | NR | 53.13% | 60.0 in metformin, 67.0 in SU (median) | Incidence of bladder cancer | / |
| Ahn et al. (2016) | Korea | Cohort study | Y | 7 | NMIBC | Metformin vs non-metformin | 46 | 84.96% | 64.6 (median) | RFS, PFS | OR |
| Wang et al. (2020) | Singapore | randomized controlled clinical trial | N | 7 | NMIBC | Metformin vs non-metformin | 102 | 82.80% | 64.7 (median) | OS, RFS, DSS | HR |
| Sung et al. (2020) | Hongkong, China | Cohort study | Y | 8 | NR | Metformin vs non-metformin | 53 | 53.08% | NR | Incidence of bladder cancer | / |
NMIBC, non-muscle-invasive bladder cancer; MIBC, muscle-invasive bladder cancer; OS, overall survival; DSS, disease-specific-survival; PFS, progression-free-survival; RFS, recurrence-free-survival; HR, hazard ratio; OR, odds ratio.