Do Men Know That They Have Had a Prostate-Specific Antigen Test? Accuracy of Self-Reports of Testing at 2 Sites

Abstract

This study determined the accuracy of self-reports of prostatespecific antigen (PSA) testing. Men (N = 402) attending 2 outpatient clinics were asked: “Did you have a PSA test today?” and their medical records were checked. Concordance, sensitivity, and false-negative values were 65%, 67%, and 33%, respectively, at 1 clinic site and 88%, 64%, and 36% at the other. The accuracy of self-reports of PSA testing should be interpreted with caution.

Screening for prostate cancer with prostate-specific antigen (PSA) is controversial because it is not clear whether regular testing reduces mortality.1–5 Therefore, professional organizations recommend informed decisionmaking for PSA testing.6–10 To promote educational efforts for informed decisionmaking and to determine screening prevalence, which often relies on selfreported data, investigators need data on the accuracy of self-reports of PSA testing. We hypothesized that the accuracy of self-reports of PSA testing would be high if patients were asked about testing on the same day as their clinic visit. We determined whether any demographic, knowledge, or experience variables predicted accurate self-reports.

METHODS

Study participants were enrolled in another study11 and attended the general internal medicine outpatient clinics at Kelsey-Seybold Clinic in Houston, Tex, and the University of Texas–Houston. Men attending KelseySeybold Clinic were scheduled for an annual health maintenance examination. Men attending the University of Texas–Houston were scheduled for nonurgent care visits.

From April to July 2001, we approached 677 men aged 50 years or older on-site after they had visited with their physician. To be eligible, men had to have no history of prostate cancer and at least a sixth-grade education. Ninety men were ineligible, and 157 refused to participate, resulting in a sample of 430 men. Each participant was paid $10 to complete a self-administered survey. A medical record review between January and March 2002 by an internal medicine physician was used as the gold standard to determine whether men had received a PSA test with their visit. After participants with unavailable records were excluded, 265 men from Kelsey-Seybold Clinic and 137 men from the University of Texas–Houston remained.

We used sections of a survey from another study.11 The main dependent variable was concordance12 of patient self-reports of PSA testing to the following question: “Did you have a PSA test today?” Independent variables were demographic, knowledge, and experience variables.

We excluded from our analysis 46 men at Kelsey-Seybold Clinic (17%) and 7 men from the University of Texas–Houston (5%) who responded “don’t know” to “Did you have a PSA test today?”

We conducted χ² tests to describe the demographic characteristics of the respondents and to assess the accuracy of PSA self-reports for independent variables. Variables significant at P ≤ .25 were entered into a stepwise logistic regression model to identify the predictors of accurate self-reports at each site.11,12

RESULTS

Respondents at the Kelsey-Seybold Clinic had a higher annual household income than did respondents at the University of Texas–Houston but otherwise had similar demographic characteristics (Table 1 ▶).

TABLE 1—

Demographic and Background Characteristics of Respondents

	Kelsey-Seybold Clinica		The University of Texas–Houstona
	n	%	n	%
Age, y
50–59	150	57	65	47
60–69	80	30	50	37
≤ 70	35	13	22	16
Race/Ethnicity
White	145	55	88	64
Hispanic	24	9	9	7
African American	81	31	37	27
Other	13	5	2	1
No response	2	1	1	1
Marital status
Married	214	81	105	77
Not married	49	18	31	23
No response	2	1	1	1
Education
< High school	18	7	15	11
Completed high school/general equivalency diploma	27	10	19	14
Some college or trade school	60	23	35	26
Bachelor’s degree	75	28	28	20
Master’s degree or beyond	84	32	39	28
No response	1	0.4	1	1
Annual household income,* $
< 15 000	5	2	13	9
15 000–99 999	180	68	73	53
≥ 100 000	65	25	45	33
No response	15	6	6	4
Family history of prostate cancer
Yes	39	15	17	12
No	217	82	117	85
No response	9	3	3	2
PSA test with clinic visit as documented in medical record**
Yes	238	90	38	28
No	27	10	99	72

^aThere were 402 study participants: 265 at Kelsey-Seybold Clinic and 137 at the University of Texas–Houston.

*P < .001 by χ² test across sites.

** P < .001 by χ² test across sites. This is the only variable that was based on the medical record review.

In response to the question “Did you have a PSA test today?” at Kelsey-Seybold Clinic, 145 men responded “yes” and 74 men responded “no.” At the University of Texas–Houston, 25 men responded “yes” and 105 men responded “no.” The concordance was 65% at Kelsey-Seybold Clinic and 88% at the University of Texas–Houston. The sensitivity and false-negative values were 67% and 33%, respectively, at Kelsey-Seybold Clinic and 64% and 36%, respectively, at the University of Texas–Houston. The specificity and false-positive values were 43% and 57%, respectively, at KelseySeybold Clinic and 98% and 2%, respectively, at the University of Texas–Houston.

At Kelsey-Seybold Clinic, 5 variables were significantly associated with accurate self-reports of PSA testing: (1) more education, (2) “ever heard of a PSA,” (3) “ever been told to have a PSA,” (4) “ever had a PSA,” and (5) “doctor recommended a PSA today” (Table 2 ▶).

TABLE 2—

Accuracy of Self-Reports of Prostate-Specific Antigen (PSA) Testing Across Experience Variables at 2 Sites

	Kelsey-Seybold Clinic		University of Texas–Houston
Experience Variables (Response Categories = Yes or No)a	Self-Report of PSA Matched Chart, %	Total Group N	Self-Report of PSA Matched Chart, %	Total Group N
Have you ever heard of a PSA test?
Yes	71*	182	88	104
No	32	28	100	1
Have you ever been told by a doctor that you should have a PSA blood test?
Yes	75*	174	87	94
No	27	33	93	29
Have you ever had a PSA test?
Yes	77*	163	88	86
No	28	40	88	34
Did your doctor recommend a PSA test to you today?
Yes	76*	162	89	87
No	33	48	85	34
Did your doctor discuss the advantages and disadvantages of the PSA test with you?
Yes	72	88	82	44
No	62	117	93	83

^aRespondents could respond “yes,” “no,” or “don’t know” to the experience variables shown. “Don’t know” responses were omitted.

*P ≤ .001 by χ² test between “yes” and “no” responses for a variable at that site only.

The prevalence of PSA testing was 90% at Kelsey-Seybold Clinic and 28% at the University of Texas–Houston by medical record review. Among the 53 men who responded “don’t know” to the question “Did you have a PSA test today?”, the prevalence of PSA testing was 91% at Kelsey-Seybold Clinic and 28% at the University of Texas–Houston. Among the 220 men who responded “yes” to the question “Did your doctor recommend a PSA test today?”, the prevalence of PSA testing was 93% at Kelsey-Seybold Clinic and 64% at the University of Texas–Houston. Among the 146 men who responded “yes” to the question “Did your doctor discuss the advantages and disadvantages of the PSA test with you?”, the prevalence of PSA testing was 88% at Kelsey-Seybold Clinic and 38% at the University of Texas–Houston.

DISCUSSION

Our findings and those of others13,14 suggest that the sensitivity of asking a man whether he had completed a PSA test is relatively low, regardless of the time frame for self-reporting a test. We found a false-negative response rate of one third, which is of concern because of the potential harm that may arise when men must cope with the consequences of a test that they did not even realize they had taken. Because professional organizations recommend informed decisionmaking before PSA testing, future studies should focus on improving physician–patient communication. We recommend caution when interpreting the accuracy of self-reports of PSA testing.