Table 2.
Linear Regression Models Estimating the Number of Additional Men Who Undergo Prostate Biopsies or Prostate Cancer Treatment and the Reduction in Deaths from Prostate Cancer, Per 100,000 Men Who Receive PSA Testing*
| Additional Men Receiving Prostate Biopsies | (95% CI) | Additional Men Treated for Prostate Cancer | (95% CI) | Reduction in Prostate Cancer Deaths in 1998–2008 | (95% CI) | Change in Deaths from Causes Other Than Prostate Cancer | (95% CI) | |
| PSA test | 4894 | (4029, 5760) | 1597 | (1087, 2106) | −61 | (−94, −29) | −448 | (−1483, 587) |
| Age 70–74 (vs 66–69) | 17 | (−140, 173) | 214 | (126, 303) | 91 | (88, 94) | 1963 | (1907, 2019) |
| % in poverty (each 1% increase) | 16 | (−19, 51) | 10 | (−11, 32) | 2 | (−0, 3) | 142 | (101, 183) |
| % Black (each 1% increase) | 13 | (6, 20) | 3 | (−1, 7) | 2 | (2, 2) | 37 | (26, 47) |
| % Uninsured (each 1% increase) | −29 | (−66, 8) | −14 | (−35, 7) | −2 | (−3, −0) | −141 | (−180, −102) |
| Housing density (each 1000 house increase) | 4 | (−8, 16) | −8 | (−18, 1) | 1 | (−1, 2) | −40 | (−91, 10) |
| HMO penetration (each 1% increase) | 1 | (−6, 7) | −2 | (−6, 1) | 0 | (−0, 0) | 5 | (−11, 1) |
| Latitude (>40° N vs 40°N) | −153 | (−333, 28) | −12 | (−118, 95) | −1 | (−10, 7) | −494 | (−729, −260) |
| Intercept | 1014 | (544, 1483) | 428 | (153, 703) | 123 | (99, 148) | 4275 | (3659, 4890) |
| R-squared | 0.076† | 0.035§ | 0.550** | 0.450 |
Notes: HMO = health maintenance organization; PSA = prostate-specific antigen.
These models examine the association of the rate PSA testing in men aged 65–74 in the 1067 U.S. counties with at least 50 relevant beneficiaries in the 5% sample of Medicare data. PSA testing rate was assessed in 1997. Biopsy and treatment rates were assessed for 1997. Prostate cancer mortality was assessed for 1998–2007. All models were weighted by the number of men aged 67–74 with parts A and B Medicare and no HMO in each county in 1997.
r-squared for PSA testing rate and biopsy rate, without the other covariates included in the regression model, was 0.06.
r-squared for PSA testing rate and treatment, without the other covariates included in the regression model, was 0.02.
r-squared for PSA testing rate and prostate cancer mortality, without the other covariates included in the regression model, was <0.002.