During 1994 to 1996, 49,905 men who were diagnosed with prostate cancer included in the SEER-Medicare database. Of these, 6,121 were African American, 3,177 were Hispanic, and 40,607 were non-Hispanic white. Of these, 7,595 were excluded from this analysis because they were aged less than 65 years at the time of diagnosis, 4,256 because they lacked continuous Medicare Part A & B coverage, 10,784 because they were enrolled in an HMO, 277 because they did not have a known month of diagnosis, 1,405 because they did not live 6 months or more after diagnosis, 610 because they were diagnosed at autopsy or by death certificate, and 4 because they were diagnosed with a second prostate cancer. After these exclusions, 24,974 men were eligible for inclusion in this study. Of these, 2,500 (10%) were African-American, 1,010 (4%) were Hispanic, and 21,464 (86%) were non-Hispanic white men.
The distribution of the mean and median value of demographic characteristics and the ecologic census tract variables varied by race/ethnic group (). The median household income for the census tracts in which African-American prostate cancer patients resided was $23,071 compared with $27,943 for Hispanics and $38,372 for whites (P < .001). African-American prostate cancer patients also more frequently lived in census tracts in which a large proportion of residents did not complete high school. The median percent of persons who did not complete high school was nearly 44% for the census tracts in which African-American prostate cancer patients lived compared with 35.8% for Hispanics and 24.4% for whites (P < .001). African Americans also were more frequently single compared with either Hispanics or whites. Although African Americans also had a slightly lower mean age at diagnosis than Hispanics and whites (73.6, 74.4, and 74.4, respectively), there was no statistically significant difference in either the mean or median age.
Demographic Characteristics of Men Diagnosed with Prostate Cancer, Surveillance, Epidemiology, and End Results 1994 to 1996. All Patients Were Entitled to Medicare in the 12 Months Prior to Diagnosis*
There were also statistically significant racial/ethnic variations in clinical characteristics, including SEER historic stage, grade, and life expectancy (). African Americans were more frequently diagnosed with distant and unstaged or unknown stage disease, less frequently diagnosed with well-differentiated tumors, and less frequently had life expectancies of 10 years or more at the time of diagnoses compared with either Hispanics or non-Hispanic whites.
Clinical Characteristics of Men Diagnosed with Prostate Cancer by Race/Ethnic Group, Surveillance, Epidemiology, and End Results 1994 to 1996
Comorbid conditions were more prevalent among African Americans than either Hispanics or whites (). Just greater than 32% of African Americans, 24.9% of Hispanics, and 22.8% of whites had at least one comorbid condition as measured by either inpatient or outpatient claims data (P < .001). Overall, the most frequently reported comorbid conditions were COPD (6.8%); DM (6.8%); malignancy other than prostate cancer (4.9%); CHF (3.5%); and cerebrovascular disease (3.3%). African Americans and Hispanics had a statistically significant higher prevalence of 4 of the 5 comorbid conditions believed to be the most likely to influence prostate cancer treatment recommendations than whites. These included CHF, COPD, DEM, and DM. The mean inpatient and outpatient comorbidity indices were significantly higher for African Americans and Hispanics than whites (data not presented).
Receipt of Watchful Waiting as Initial Therapy
African Americans and Hispanics were significantly more likely than whites to receive watchful waiting for the initial management of their prostate cancer. Overall, 23.8% of men eligible for this study received watchful waiting. However, nearly 29% of African Americans and 28.4% of Hispanics received watchful waiting compared with 23% of whites. In univariate logistic regression analyses that separately examined clinical characteristics, race/ethnic group, age, stage, grade, and life expectancy, inpatient comorbidity index, outpatient comorbidity index, CHF, DEM, and COPD were significantly associated with the receipt of watchful waiting (data not presented) and were entered into a multivariate model.
Several factors, including race and ethnicity, were found to be independently associated with the receipt of watchful waiting in multivariate logistic analyses after adjustment for clinical characteristics (). In a model adjusted for age, comorbidity, stage, grade, and life expectancy (Model 2), African-American (odds ratio [OR], 1.4; 95% confidence interval [CI], 1.3 to 1.6) and Hispanic men (OR, 1.3; 95% CI, 1.1 to 1.5) were significantly more likely than white men to receive watchful waiting. Advanced stage and grade were associated with an increased odds of receiving watchful waiting, while life expectancy < 10 years, increased age, and comorbidity were associated with lower odds of receiving watchful waiting.
Multivariate Logistic Regression Analysis of the Receipt of “Watchful Waiting” as Initial Therapy for Prostate Cancer Among Men Aged 65 and Older, Surveillance, Epidemiology, and End Results-Medicare 1994 to 1996
In a third multivariate model additionally adjusted for demographic characteristics (marital status, income, and education), the odds of receiving watchful waiting for African-American (OR, 1.3; 95% CI, 1.1 to 1.4) and Hispanic men (OR, 1.2; 95% CI, 1.03 to 1.4) were slightly reduced but remained significantly higher than those of white men. There were little or no changes in the ORs for stage, grade, life expectancy, age, and comorbidity. Men who were single or separated, with incomes less than $40,000, or who lived in census tracts where 30% or more of the population did not complete high school were significantly more likely to receive watchful waiting than were men without these characteristics.
Because of the independent association of race/ethnicity with the receipt of watchful waiting after controlling for relevant clinical and sociodemographic variables, we examined racial/ethnic differences in factors that influenced receipt of watchful waiting in race/ethnic group-stratified multivariate logistic regression analyses in a manner analogous to the analyses for the overall sample ().
Race-Stratified Multivariate Logistic Regression of the Receipt Among Watchful Waiting, Surveillance, Epidemiology, and End Results-Medicare 1994 to 1996
In general, there were few racial/ethnic differences in clinical factors associated with the receipt of watchful waiting. Among African Americans and whites, watchful waiting was significantly more frequently received among men with in situ, local, or unstaged/unknown disease and men with high inpatient or outpatient comorbidity indices. Although Hispanic men with unstaged/unknown disease or with a high inpatient comorbidity index were also somewhat more likely to receive watchful waiting, this was not a statistically significant finding. A high outpatient comorbidity index was not significantly associated with the receipt of watchful waiting among Hispanic men. The receipt of watchful waiting increased by approximately 8% for each year increase in age for African Americans, by 9% for whites, and by 4% for Hispanics. Higher grade was associated with a decrease in the odds of receiving watchful waiting for all three racial/ethnic groups. The odds of receiving watchful waiting among same race/ethnic group men with incomes < $30,000 compared with men with incomes of $40,000 or more was 1.7 (95% CI, 0.9 to 3.1) for Hispanics, 1.4 (95% CI, 0.95 to 2.0) for African Americans, and 1.1 (95% CI, 1.0 to 1.2) for whites. Similarly, among same race/ethnic group men who lived in census tracts where 30% or more of the population had not completed high school compared with those who lived in census tracts where < 20% of the population had not completed high school, the odds of the receipt of watchful waiting were 2.1 (95% CI, 1.5 to 3.0) for Hispanics and 1.3 (95% CI, 1.0 to 1.7) for African Americans compared with 1.1 (95% CI, 1.1 to 1.3) for whites.