Table 2.
Comparison of the user groups versus the never-user groups
| Thiazolidinedione ever-users | Thiazolidinedione never-users | Statistical test | P | |
| Black race | 11/61 (18.0%) | 30/172 (17.4%) | χ2 | 0.927 |
| Age of diagnosis (years) | Mean = 61.69 | Mean = 64.12 | t | 0.060 |
| Gleason grade | Median = 8 | Median = 8 | Mann–Whitney rank sum | 0.236 |
| TNM stage ≥3 | 26/56 (46.43%) | 93/160 (58.1%) | χ2 | 0.174 |
| PSA at diagnosis | Median = 9.3 | Median = 15.7 | Mann–Whitney rank sum | 0.147 |
| BMI | Median = 30.58 | Median = 30.27 | Mann–Whitney rank sum | 0.525 |
| Metformin ever-users | Metformin never-users | Statistical test | P | |
| Black race | 26/132 (19.7%) | 15/101 (14.8%) | χ2 | 0.430 |
| Age of diagnosis (years) | Mean = 61.29 | Mean = 66.39 | t | <0.001 |
| Gleason grade | Median = 8 | Median = 8 | Mann–Whitney rank sum | 0.502 |
| TNM stage ≥3 | 48/93 (51.6%) | 70/122 (57.4%) | χ2 | 0.482 |
| PSA at diagnosis | Median = 15.9 | Median = 11.2 | Mann–Whitney rank sum | 0.112 |
| BMI | Median = 30.33 | Median = 29.48 | Mann–Whitney rank sum | 0.364 |
| Metformin ± thiazolidinediones ever-users | Metformin ± thiazolidinediones never-users | Statistical test | P | |
| Black race | 24/160 (15%) | 17/73 (23.3%) | χ2 | 0.182 |
| Age of diagnosis (years) | Mean = 64.14 | Mean = 62.03 | t | 0.122 |
| Gleason grade | Median = 8 | Median = 8 | Mann–Whitney rank sum | 0.147 |
| TNM stage ≥3 | 80/93 (53.7%) | 38/67 (56.7%) | χ2 | 0.190 |
| PSA at diagnosis | Median = 11.7 | Median = 16.42 | Mann–Whitney rank sum | 0.935 |
| BMI | Median = 29.74 | Median = 31.27 | Mann–Whitney rank sum | 0.208 |
TNM, tumour–node–metastasis; PSA, prostate-specific antigen; BMI, body mass index.