Table 1. Percentage Difference in PSA Levels According to Length of Time on Antidiabetic Medications Prior to PSA Testa.
| Length of Time Using Medication Before PSA Test, mo | No. Exposed | Difference (95% CI), % | P Value |
|---|---|---|---|
| First antidiabetic, any | |||
| Duration before PSA test | 4424 | –0.9 (–2.3 to 0.5) | .21 |
| 1-6 | 1741 | –2.0 (–4.2 to 0.2) | .07 |
| 7-12 | 1433 | 0.2 (–1.9 to 2.4) | .86 |
| 13-18 | 737 | –0.6 (–3.7 to 2.6) | .71 |
| 19-24 | 513 | –0.2 (–3.8 to 3.4) | .90 |
| Metformin | |||
| Duration before PSA test | 4583 | –0.7 (–2.1 to 0.8) | .38 |
| 1-6 | 1799 | –1.0 (–3.2 to 1.1) | .35 |
| 7-12 | 1491 | –0.4 (–2.5 to 1.8) | .75 |
| 13-18 | 767 | 0.1 (–3.1 to 3.3) | .95 |
| 19-24 | 526 | –1.2 (–4.9 to 2.4) | .51 |
| Sulfonylurea | |||
| Duration before PSA test | 1104 | 4.1 (–0.8 to 9.1) | .10 |
| 1-6 | 431 | 5.2 (–0.7 to 11.1) | .08 |
| 7-12 | 366 | 5.5 (–0.5 to 11.5) | .07 |
| 13-18 | 171 | 0.4 (–6.1 to 6.9) | .90 |
| 19-24 | 136 | 5.0 (–3.1 to 13.2) | .22 |
| Insulin | |||
| Duration before PSA test | 978 | –6.5 (–13.8 to 0.8) | .08 |
| 1-6 | 404 | –9.4 (–18.0 to –0.9) | .03 |
| 7-12 | 301 | –2.0 (–10.2 to 6.3) | .64 |
| 13-18 | 171 | –6.1 (–15.9 to 3.7) | .22 |
| 19-24 | 102 | –3.6 (–14.7 to 7.5) | .53 |
Abbreviation: PSA, prostate-specific antigen.
SI conversion factor: To convert PSA to μg/L, multiply by 1.0.
a
Derived from multivariable linear regression for (log-transformed) PSA at follow-up, adjusted for premedication PSA (log-transformed), education, civil status, Charlson Comorbidity Index, family history of prostate cancer, test year, duration between tests and exposure to other antidiabetic medications prior to the second PSA test. Comparison groups consisted of men not previously exposed to the specific class of antidiabetic medication age matched at follow-up PSA test (5:1).