PREVENTiVE

MEDICINE

21, 395-104

(1992)

Breast and Cervical Cancer Screening The San Diego

Medicare

in Older Women:

Preventive

Health

Project’

JONI A. MAYER, PH.D.,~ DONALD J. SLYMEN, PH.D., JOSEPH A. DREW, B.A., BRIDGET L. WRIGHT, M.P.H., JOHN P. ELDER, PH.D., M.P.H., AND STEPHEN J. WILLIAMS, Sc.D. Graduare

School

of Public

Health,

San Diego

State

University,

San Diego,

CA 92I82

Background. This study presents rates and correlates of cancer screening, including mammography, clinical breast exam, breast self-examination, and Pap tests, in older women. Age was the predictor of main interest. Resulfs. Among a sample of female Medicare beneficiaries ages 65 and older, who were members of a health maintenance organization, there was a significant, inverse relationship between age and mammography adherence, while controlling for health status, physician utilization, education, and income. The proportions of subjects ages 65-74 and 75 + never having had a mammogram were 17 and 32%. respectively, and the proportions having had annual mammograms were 40 and 28%, respectively. Pap test frequency showed a trend toward an inverse relationship with age, controlling for demographic and health-related variables. In the youngest age group (65-69), 52% had annual Pap tests, whereas in the oldest group (80+ ), only 36% had annual Pap tests. Age did not predict frequency of clinical breast exam, and the relationship of age to breast self-examination was inconclusive. The o 1992 Academic press. 1”~. role of the physician in promoting cancer screening is discussed.

INTRODUCTION Previous studies have indicated that the prevalence of cancer screening decreases with age in older cohorts. For example, among women 50 years and older, inverse relationships have been found between age and the frequency of mammograms (l-6), clinical breast exams (CBE) (3, 6-8), receipt of breast selfexamination (BSE) instructions by a health professional (8), frequency of BSE practice (2, 3), and Pap tests (6, 8). These inverse relationships are disturbing, because for breast cancer, incidence and mortality rates increase with age, and the combination of early detection and treatment is as efficacious in elderly women as it is in younger women (9). Additionally, although elderly women have lower incidence rates of carcinoma in situ of the cervix than younger women, they have higher incidence rates of invasive cervical cancer and higher mortality rates due to cervical cancer (10). Consequently, Pap smear screening is thought to be a cost-effective screening procedure for women 65 years and older (10). ’ This study was based on research supported by Contract 95-C-99160/9-03 from the U.S. Health Care Financing Administration and by a grant from PacifiCarc Health Systems, Inc./Secure Horizons of California. It was funded by a cumulative federal grant of $1.2 million and $150,000 of nonfederal funds (federal support equals 89% of project: nonfederal support equals 11% of project). * To whom reprint requests should be addressed. 395 0091.7435192

$5.00

Copyright 0 1992 by Academic Press, Inc. All rights of reproductmn m any form reserved.

396

MAYER

ET AL.

In a recent report (1 l), we presented preliminary (65+) of health maintenance organization (HMO) relationship between age and mammography. This and additionally explores the relationship between screening (i.e., CBE and BSE) and cervical cancer cedures .

data from an older sample members showing an inverse article extends those findings age and other breast cancer screening (i.e., Pap test) pro-

METHODS

Subjects (n = 995) were female members, ages 265 years, of a Medicare risk-based capitational HMO who had been randomly selected and had agreed to participate in a controlled trial of the cost-effectiveness of preventive services (12). Costs for CBE, Pap tests, and mammograms ordered by health plan physicians were covered by the plan, even though Medicare, at the time of the study, did not cover screening mammograms. The subjects who reported a prior history of any site of cancer (n = 145) or who did not respond to the cancer history question (n = 31) were excluded from all analyses, leaving a sample size of 819. The numbers of subjects in the age groups 65-69,70-74,75-79, and 380 were 244, 301, 189, and 85, respectively. The data were collected during the summer of 1989 via a paper-and-pencil health appraisal prior to randomization to treatment or control groups. The screening frequency questions targeted mammography, CBE, BSE, and Pap tests and were asked as multiple-choice questions (see Table 2). Number of outpatient physician visits in the past year was asked in an open-ended question, and health status was rated on a Likert scale, from 1 (“poor”) to 5 (“excellent”). Income and education were assessed with multiple-choice questions and were subsequently coded into four and three categories, respectively (see Table 1). Finally, age, which was asked in an open-ended question, was categorized into four categories. Since frequency of mammogram, CBE, BSE, and Pap tests were ordinal dependent variables, cumulative odds ordinal regression models were fitted to assess the relationship with age alone, and with age controlling for the selected characteristics described above (13). Goodness-of-fit tests for age alone suggested the ordinal regression model was appropriate for mammography (P = 0.47), CBE (P = 0.96), and Pap test (P = 0.59). However, for BSE, this model yielded a poor fit (P = 0.028). Therefore, an unordered polychotomous logistic regression model was used for BSE (14). RESULTS

Table 1 presents the distributions across age categories of income, health status, education, and physician visits. As shown by x2 tests, income and education were differentially distributed across age groups, while health status and doctor visits were not differentially distributed. The sample was predominantly white (95%), 57% had completed at least some college, and 40% had a household income of $20,00O/year or above. Eighty-four percent rated their health as “good” or better. The majority of subjects (88%) had had two or more outpatient physician visits in the past year, with a median of four visits. Subjects in the age groups of 65-69, 70-74, 75-79, and 280 had been members of the HMO for mean durations

SCREENING

IN OLDER

TABLE DISTRIBUTIONS

OF SELECTED

SAMPLE

397

WOMEN

1 CHARACTERISTICS

BY AGE GROUP

Age group

Income (in thousands) 12 Doctor visits (per year) Cl >l u Based

P

IO-74

75-19

80+

value0

(n = 230)

(n = 284)

(n = 175)

(n = 82)

0.000

11.8 35.7 36.5 16.1 = 243) 13.2 31.1 33.7 21.4 = 242) 9.5 30.2 60.3 = 216) 12.0 88.0

16.9 44.7 27.1 11.3 = 298) 16.1 30.2 31.2 22.5 = 294) 7.8 36.7 55.4 = 274) 12.8 87.2

25.1 40.0 26.3 8.6 = 183) 14.2 37.2 30.0 18.6 = 181) 14.9 32.6 52.5

6549

(n

(n

(n

(n

(n

(n

(n

(n

(n = 159) 10.7 89.3

36.6 36.6 19.5 1.3

(n = 82)

0.466

20.7 34.2 32.9 12.2

(n = 77) 24.7 18.2 57.1 (n = 70) 14.3 85.7

0.000

0.871

on x2 tests.

of 26.4 (SD = 12.6), 32.3 (SD = 11.1), 33.0 (SD = 10.6), and 32.1 (SD = 11.5) months, respectively. Table 2 shows that age was strongly associated with mammography. The distributions clearly indicated that frequency of mammogram declined with age. Age was not related to CBE (P = 0.115). The trend in the distributions suggested that frequency of CBE declined with age; however, it was not strong. The distribution for BSE did not suggest a clear pattern, even though its association with age was statistically significant (P = 0.017). Specifically, although the first three age groups suggested a decline of frequency of BSE with age, the 80-t group did not follow this trend. Finally, age showed a significant inverse relationship with Pap tests, with responses of “almost never” increasing with age and responses of “every year” decreasing with age. The multivariate models assessed the relationships of each outcome measure to age and selected characteristics simultaneously. The ordered categories for mammography, CBE, and Pap test shown in Table 2 were used in the ordinal regressions. The categories for BSE were treated as unordered in a polychotomous logistic regression. We modeled the frequency of each screening procedure as a function of age, income, health status, education, and doctor visits. Tables 3 through 6 show the adjusted prevalence odds ratio estimates, 95% confidence intervals for the estimates, and P-values for a test of significance of the association between the variable and the outcome, adjusted for the other variables in the model. As shown in Table 3, age, income, and doctor visits were significantly associated with frequency of mammography. The adjusted prevalence odds ratios for

MAYER ET AL.

398

TABLE DISTRIBUTIONS

OF FREQUENCY

2

OF SCREENING

PROCEDURES

BY AGE

GROUP

Age group

Mammogram Never Every few years Every year Clinical breast exam Never Every 2-5 years Every year Breast self-exam Never Every few months Every month Pap test Almost never Every few years Every 2 years Every year

P

65-69

70-74

15-79

(n = 204) 17.7 39.7 42.7 (n = 204) 6.4 29.4 64.2 (n = 208) 14.4 50.0 35.6 (n = 241) 10.0 26.6 11.2 52.3

(n = 242) 17.4 45.5 37.2 (II = 248) 6.1 27.4 66.5 (n = 244) 19.7 45.9 34.4

= 152) 30.3 40.8 29.0 (n = 159) 8.2 34.0 57.9 (n = 158) 27.9 41.8 30.4 (n = 187) 18.2 30.0 13.9 38.0

(n

= 293)

14.0 24.9 16.4 44.7

(n

80+ (n =

66)

value 0.0004”

34.9 39.4 25.8 (n = 70) 11.4 34.3 54.3

0.115”

(n =

0.093b

69)

15.9 60.9 23.2 (n

= 81)

0.0015”

23.5 29.6 11.1 35.8

’ Based on a cumulative odds ordinal regression model. Dummy variables were used to represent the age groups. Each test follows approximately a x2 distribution, with 3 df. ’ Based on an unordered polychotomous logistic regression. The test follows approximately a x2 distribution, with 6 df

age suggested that the frequency of a mammogram decreased with age. Women in the 75-79 and 80+ groups obtained a mammogram less frequently than the younger age categories. The frequency of a mammogram tended to increase with income. Also, more than one doctor visit was positively associated with frequency of mammogram. Neither health status nor education demonstrated a relationship with mammogram after adjustment. As shown in Table 4, after adjustment, age had a weak, borderline significant (P = 0.08) inverse relationship with CBE frequency. Both income (P = 0.005) and doctor visits (P = 0.013) were positively associated with frequency of CBE. The association between BSE and age remained significant (P = 0.025) after adjustment. Although a decrease in BSE frequency with age was suggested among the first three age groups, the decrease was not sustained in the 80+ group. Income (P = 0.036) and health status (P = 0.002) were also associated with BSE; however, the patterns were difficult to interpret (see Table 5). Finally, as shown in Table 6, age showed a trend (P = 0.057) toward an inverse relationship with Pap test frequency. Income and number of doctor visits were positively associated with Pap test frequency. DISCUSSION

To our knowledge, the prevalence of breast and cervical cancer screening previously had not been studied in a relatively large, older adult sample belonging to

SCREENING

TABLE MULTIVARIATE

399

IN OLDER WOMEN 3

ORDINAL REGRESSION MODEL TO ASSESS THE RELATIONSHIP OF FREQUENCY MAMMOGRAM TO SELECTED CHARACTERISTICS (n = 544)

Factor Age (years)

Income (in thousands) Health status

Education (years) Doctor visits (per year)

Categories 65-69 70-74 75-79 280 I

Odds ratio -~~.

95% confidence interval

1”

1.1 0.58 0.54 1” 1.4 2.1 2.9 I” 0.82 1.1 0.87 1” 0.86 1.0 1” 2.4

OF

P value 0.012

0.73-1.6 0.37-0.91 0.29-I .o 0.002 0.88-2.2 1.3-3.4 1.6-5.4 0.40 0.50-1.3 0.70-I .9 0.50-t .5 0.69 0.48-I .5 0.57-l .7 0.001 1.4-3.9

’ Reference category.

an HMO. In this study, there was a clear, inverse relationship between age and mammography, which replicated results from previous surveys (l-6). When health status and number of physician visits were included in the analysis, along with income and education, the relationship between age and mammography persisted. A similar relationship was found between age and Pap tests, although the level of significance was borderline (P = 0.057). Ruling out health status and physician visits as potential confounders is important, because two possible explanations for the inverse relationship between age and screening are (a) the treatment of acute and chronic health problems in the older women may take precedence over preventive procedures or (b) poor health status may impede access (e.g., reduced mobility) to health facilities. Our data support the hypothesis that although the older women (75 +) are interacting with physicians at frequencies comparable to that of women 65-74, less emphasis is placed on secondary prevention for the older group. This finding cannot be accounted for by differential self-reported health status across the age groups. The results of a national survey also found an inverse effect of age on mammography and Pap screening while controlling for health status and frequency of physician visits (6). That study additionally found an inverse age-CBE relationship. The primary measures used in this study were obtained by self-report via a questionnaire. In recent studies, reports of mammography compliance from a telephone survey of HMO members were found to be highly accurate (15), whereas accuracy of reporting “last Pap smear” among rural African American women was relatively low (16). In another study, self-reported health status pre-

MAYER

400

ET AL.

TABLE MULTIVARIATE ORDINAL

4

REGRESSION MODEL TO ASSESS THE RELATIONSHIP CBE TO SELECTED CHARACTERISTICS (n = 556) 95%

Factor Age (years)

Income (in thousands) Health status

Education (years)

Odds ratio

65-69

m-74

1” 1.5

15-79 280

0.85 0.88

l

0.96

OF FREQUENCY

OF

P value 0.080

0.96-2.3 0.53-1.4 0.46-1.7 0.005

0.82 0.70-2.0 0.53-1.7

1”

0.55

0.88

0.48-1.6

1.1 1” 1.9

0.61-1.9 0.013

1.2-3.2

n Reference category.

dieted mortality and successful aging, independent of objective health status (17). Limitations related to the measurement of screening prevalence include (a) we did not assess the total (cumulative) number of each screening procedure or time since the last procedure and (b) the questionnaire did not differentiate between routine and diagnostic tests. Exclusion of subjects reporting a history of cancer of any site may have biased the sample with respect to responses on screening, physician utilization, and health status variables. Finally, the proportions of missing data for the outcome variables ranged from 2 to 19%, although for each outcome, the response rates were comparable across age groups. Breast and cervical cancer screening guidelines of the American Cancer Society (ACS) applicable to women age 65 and older are annual mammography and CBE, monthly BSE, and annual Pap test (with less frequent Pap tests at the discretion of the physician following three consecutive annual negative tests) (18). Screening objectives for the Year 2000 specific to women 70 and older have been proposed (19), and Table 7 presents those objectives juxtaposed with the unadjusted rates for our sample, with subjects younger than 70 deleted. As shown, for CBE, the rates for our samples exceeded the targets. For having “ever” received a mammogram and Pap test (the category for which our study had a parallel response option), our rates were somewhat, but not substantially, lower than the target rates. The lack of or relatively small discrepancies between our 1989 rates and the Year 2000 targets are not surprising, considering the demographic characteristics and greater access to health services of the study sample compared with those of the general population. Yet, of our entire sample, over one-fifth had never had a

SCREENING

401

IN OLDER WOMEN TABLE

5

MULTIVARIATE UNORDERED POLYCHOTOMOUS LOGISTIC REGRESSIONMODEL TO ASSESS THE RELATIONSHIP OF FREOUENCY OF BSE TO SELECTED CHARACTERISTICS (n = 559)

Every montha Factor Age (years)

Income (in thousands) Health status

Education (years) Doctor visits (per year)

Categories

OR

65-69 70-74 75-79 280 l

lb 0.74 0.42 0.75 lb 1.7 2.3 0.71 lb 2.0 1.4 1.5 lb 0.74 0.62 lb 1.7

95% CI 0.40-l .4 0.21-0.84 0.25-2.2 0.87-3.4 1.1-5.0 0.29-1.7 0.88-4.3 0.64-2.9 0.67-3.3 0.30-1.8 0.26-l .5 0.82-3.6

Every few monthsa OR lb 0.61 0.38 1.3 lb 1.9 2.7 1.0 lb 2.1 1.2 0.59 lb 1.1 0.75 lb 1.2

95% CI

P

value 0.025

0.34-1.1 0.20-0.72 0.48-3.4 0.036 1.0-3.7 1.3-5.7 0.46-2.4 0.002 1.0-4.4 0.58-2.3 0.27-l .3 0.52 0.45-2.6 0.33-l .7 0.30 0.59-2.3

a Reference category is “never.” b Reference category.

mammogram, only 63% were having annual CBEs, only one-third were having both annual CBEs and annual mammograms, only one-third were performing monthly BSE, and only 45% were having annual Pap smears. Thus, adherence to the ACS guidelines for each procedure was far from optimal. Given that (a) the economic barriers to health care for this HMO population were minimal, (b) women age 70 may be expected to live at least 15 more years (20), (c) this age segment of the population is growing (20), and (d) early detection and treatment for this age group is efficacious (9), the results of this study are particularly disturbing. Our findings regarding screening rates may not be generalizable to elderly women who are not members of an HMO. Moreover, although subjects in the study were randomly selected from all HMO members, those subjects who agreed to participate may have been more health conscious than refusers. Additionally, it is possible that “noncompliers” were overrepresented in the missing data for each outcome variable. Thus, our data may overestimate the compliance rates of the HMO used in this study. In a recent study that assessed mammography rates of women belonging to an HMO from 1981 to 1989 in Madison, Wisconsin, 68% of the subjects 265 years old had at least one mammogram in the 8-year interval (21). Approximately 78% of our sample had “ever” had a mammogram. The Madison data were based on chart review and covered only an 8-year interval and thus are a more conservative estimate of compliance. In a telephone survey conducted in late 1987-early 1988

402

MAYER ET AL. TABLE

MULTIVARIATE

ORDINAL REGRESSION MODEL PAP TEST TO SELECTED

Factor Age (years)

Income (in thousands) Health status

Education (years) Doctor visits (per year) Abnormal Pap

6

TO ASSESS THE RELATIONSHIP CHARACTERISTICS (n = 619)

Categories

Odds ratio

65-69 70-74 75-79 ~80 l No Yes

1” 0.98 0.65 0.58 1” 1.4 1.7 2.4 1” 1.1 1.1 1.2 1” 1.0 1.2 1” 2.3 1” 1.1

OF FREQUENCY

95% confidence interval

OF

P value 0.057

0.68-l .4 0.43X1.98 0.33-l .o 0.020 0.90-2.1 1.1-2.7 1.34.4 0.84 0.67-l .7 0.72-l .8 0.74-2.1 0.49 0.61-l .7 0.74-2.0 0.0005 1.4-3.6 0.86 0.60-l .8

’ Reference category.

TABLE YEAR

2000 OBJECTIVES

7

(19) FOR WOMEN 70+ AND UNADJUSTED SUBJECTS 70+

SCREENING

RATES FOR

Objectives

CBE Ever received Received within preceding 2 years Mammography Ever received Received within preceding 2 years Monthly BSEb Pap test Ever received Received within preceding 3 years

1987 Baseline (%)

2000 Target (%)

This study (%I

25 18

80 60

93 62”

25 18 -

80 60 -

76 33” 31

76 44

95 70

83 56’

LIProportion who reported annual frequency. No comparable response option was available. ’ No objectives proposed. ’ Proportion who reported frequency of every 2 years or more often. No comparable response option was available.

SCREENING

IN

OLDER

WOMEN

403

in Los Angeles, California, 69%of women 365 years old who had used prepaid programsreportedhaving had at least one mammogram,whereasthe prevalence of mammography for all subjects in this age group, collapsing across regular source of care (including none), was 54% (22). In the Mammography Attitudes and Usage Study, a national survey conducted in 1990,65% of women ages 60-69 and 56% of women ages 270 reported ever having had a mammogram (23). Comparing the higher rates from our study and others that assessed HMO members with national data collected during the same time indicates the importance of acknowledging the source of health care in assessing and/or predicting compliance among older women, at least for mammography. CONCLUSION

In planning interventions to remedy low adherence to screening guidelines among older women, the role of the physician should be emphasized. For example, physician referral has consistently predicted whether a woman has a mammogram (1,4,5,24,25), and a recent study found discussion of mammography by one’s physician to be particularly important for women 65 and older (22). Physicians’ perceptions regarding the role of prevention for aging female patients need to be researched further. Additionally, the potential for physicians to promote cancer screening may vary according to the structure of the provider organization and physician financial incentives; the nature of this variation is also worthy of study. Across all types of health care settings, educational programs for both physicians and patients, combined with Medicare coverage of preventive services, are needed to facilitate screening guideline adherence for older women. ACKNOWLEDGMENT We thank Genevieve Offner for assistance in preparing the manuscript.

REFERENCES 1. Centers for Disease Control. Use of mammography for breast cancer screening-Rhode Island, 1987. MMWR 1988; 37:357-360. 2. Chao A, Paganini-Hill A, Ross RK, Henderson BE. Use of preventive care by the elderly. Prev Med 1987; 16:710-722. 3. Dawson DA, Thompson GB. Breast cancer risk factors and screening: United States, 1987. National Center for Health Statistics. Viral Health Star 1989; lO(l72). 4. Lerman C, Rimer B, Track B, Balshem A, Engstrom PF. Factors associated with repeat adherence to breast cancer screening. Prev Med 1990; 19:1-12. 5. Zapka JG, Stoddard AM, Costanza ME, Greene HL. Breast cancer screening by mammography: Utilization and associated factors. Am J Public Health 1989; 791,499-l ,502. 6. Hayward RA, Shapiro MF, Freeman HE, Corey CR. Who gets screening for cervical and breast cancer? Arch Intern Med 1988; 148:1,177-1,181. 7. Makuc DM, Freid VM, Kleinman JC. National trends in the use of preventive health care by women. Am J Public Health 1989; 79:21-26. 8. Celentano DD, Shapiro S, Weisman CS. Cancer preventive screening among elderly women. Prev Med 1982; 11:454-463. 9. Yancik R, Ries LG, Yates JW. Breast cancer in aging women. Cancer 1989; 63:976-981. 10. U.S. Congress, Offtce of Technology Assessment. The Costs and Effectiveness of Screening for Cervical Cancer in Elderly Women-Background Paper. OTA-BP-H-65. Washington, DC: Government Printing Office, February 1990.

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ET AL.

11. Mayer JA, Slymen DJ, Drew JA, Wright BL, Elder JP, Williams SJ. The relationship between age and mammography in older women: [letter]. Am J Public Health, 1992$X2:755. 12. Golembesky H, Williams SJ, Nordquist JR, Scutchtield FD. The San Diego Medicare Preventive Health Project: A joint research effort in the community. San Diego Physician 1990; 77:21-22. 13. Armstrong BG, Sloan M. Ordinal regression models for epidemiologic data. Am J Epidemiol 1989; 129:191-204. 14. Hosmer DW, Lemeshow S. Applied Logistic Regression. New York: Wiley, 1989:216-238. 15. King ES, Rimer BK, Track B, Balshem BA, Engstrom P. How valid are mammography selfreports? Am J Public Health 1990; 80:1,386-1,388. 16. Sawyer JA, Earp JA, Fletcher RH, Daye FF, Wynn FM. Accuracy of women’s self-report of their last Pap smear. Am J Public Health 1989; 79:1,036-l ,037. 17. Roos NP, Havens B. Predictors of successful aging: A twelve-year study of Manitoba elderly. Am J Public Health 1991; 81:63-68. 18. American Cancer Society. Cancer Facts and Figures-1991. Atlanta, GA: American Cancer Society, 1991. 19. U.S. Department of Health and Human Services. Healthy People 2000: National Health Promotion and Disease Prevention Objectives. DHHS Publication No. (PHS) 91-50212. Washington, DC: U.S. Department of Health and Human Services, 1990. 20. U.S. Special Committee on Aging. Health status and health services utilization. In: Aging America: Projections and Trends. Washington, DC: U.S. Department of Health and Human Services, 1987. 21. Hansen JP, Knapp PA, Newcomb PA. Mammography in a health maintenance organization. Am J Public Health 1991; 81:1,489-l ,490. 22. Fox SA, Murata PJ, Stein JA. The impact of physician compliance on screening mammography for older women. Arch Intern Med 1991; 151:X3-56. 23. Centers for Disease Control. Use of mammography-United States, 1990. MMWR 1990; 39:621630.

Kruse J, Phillips DM. Factors influencing women’s decision to undergo mammography. Ubstet Gynecol 1987; 70~744-748. 25. Rimer BK, Keintz MK, Kessler HB, Engstrom PF, Rosan JR. Why women resist screening mammography: Patient-related barriers. Radiology 1989; 172:243-246. 24.

Received October 8, 1991 Revised January IO, 1992 Accepted January 27, 1992

Breast and cervical cancer screening in older women: the San Diego Medicare Preventive Health Project.

This study presents rates and correlates of cancer screening, including mammography, clinical breast exam, breast self-examination, and Pap tests, in ...
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