| HOME | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|---|
| ||||||||||||||||||||||||||||||||
a Presbyterian/St. Luke's Medical Center and GeriMed of America, Inc., Denver, Colorado
b St. Joseph Healthcare, Albuquerque, New Mexico
c Hilton Head Medical Center, Hilton Head, South Carolina
d University of Colorado Health Sciences Center, Denver
e HealthONE Alliance Research, Denver, Colorado
Donald J. Murphy, 1721 E. 19th Ave., Suite 574, Denver, CO 80218 E-mail: DonJMurphy{at}aol.com.
| Abstract |
|---|
|
|
|---|
Methods. At the end of routine office visits, we surveyed all eligible consecutive patients who visited four geriatricians in a Denver practice between November 8, 1993, and February 9, 1994.
Results. We saw a total of 675 outpatients during the study period and completed the interview with 409 patients (75% female, mean age 81, 78% Caucasian). We found a strong correlation between (i) increased probability of detecting cancer and greater preference for cancer screening tests (p < .001) and (ii) increased probability of preventing disease (heart attack, stroke, or hip fracture) and greater preference for preventive medication (p < .0001). There was notable variability in seniors' preferences for a given therapy at each absolute risk threshold. For example, 15% of seniors did not think that highly effective, inexpensive medications to prevent heart attacks were worthwhile for them. At the other end of the spectrum, 22% of seniors felt that low-yield, costly medications to prevent heart attacks were worthwhile.
Conclusions. Seniors readily understand the probability of benefit expressed in terms of absolute risk reduction. Furthermore, probability of benefit strongly influences seniors' preferences for cancer screening and preventive medication use. Finally, there is variety in the thresholds of prevention at which individuals are willing to accept preventive treatment. The probability of benefit is an essential and useful element for seniors to make informed decisions about routine health services.
HEALTH care providers routinely and frequently screen patients for cancer and prescribe medications to prevent disease. Many guidelines are available to shape recommendations for detecting early disease and for preventing the progression of disease (1)(2)(3)(4). However, ethical justification for preventive interventions, such as cancer screening and preventive medication, depends not only on the benefits to the sick, but also on risks and costs to the healthy (5). Surprisingly few data are available that indicate how patients value the risk-reduction benefit of preventive interventions.
Respect for patient autonomy has emerged as a guiding principle in medical practice. A tangible manifestation of this principle is informed consent, which recent publications have emphasized as an important component in selecting preventive interventions (6)(7)(8)(9)(10). In 1989, Brett distinguished the effects of statistical reporting methods, asserting that "physicians and patients are likely to perceive a relative benefit of 20 or 30 percent more favorably than an absolute benefit of 1 or 2 percentage points" (11). To meaningfully and adequately inform a patient about the individual benefit of a preventive intervention, the practitioner must present the absolute risk reduction (12)(13)(14)(15).
As primary care providers, we wanted to determine the influence of absolute risk reduction information on our patients' preferences for cancer screening and the use of medications to prevent common diseases, such as myocardial infarction, stroke, and hip fracture. The impact of the probability of benefit on these preferences is important for several reasons. First, a correlation between increased absolute risk reduction and greater preference for a preventive intervention reinforces the value of including statistical information in helping a patient make an informed decision. Second, variability in response to prevention odds reveals that certain patients may or may not follow the trend, thus emphasizing the importance of individualized care. A decision to treat will depend in part on the patient's value of risk reduction and not simply on a universal recommendation based only on statistical evidence. This individualized approach may elucidate problems with patient care. For example, noncompliance may be an obstacle if a patient values risk reduction differently than a group of experts or a primary care physician. Finally, more information about patients' preferences regarding preventive interventions should help shape future guidelines, particularly as new preventive therapies arise (16).
| Methods |
|---|
|
|
|---|
We surveyed all eligible consecutive patients who visited three clinicians between November 8, 1993, and February 9, 1994. The fourth clinician had a nurse practitioner interview all of his eligible consecutive patients at a satellite clinic. Interviewers included three physicians, one geriatric nurse practitioner, and two medical residents. We conducted the interviews at the end of routine office visits. Most interviews lasted 5 to 8 minutes.
The questionnaire was divided into five sections. The first section focused on the patient's preferences for cancer screening that involved (i) a simple blood test; (ii) a test requiring an extra appointment and some discomfort; and (iii) a similar test requiring out-of-pocket expenses (i.e., ones that "put a strain on the pocketbook that month").
The second, third, and fourth sections focused on the patient's preferences for medications to prevent heart attacks, strokes, and hip fractures, respectively. In each of these sections, we presented one question when the patient assumed the medication costs were very small. We presented another question when the patient assumed the cost of the medication "put a strain on the pocketbook." We used the same thresholds for absolute risk reduction (50%, 10%, 5%, 2%, 1%, and 0.02%) in each of these three sections. We presented these thresholds in terms of probabilities, e.g., "a 1 in 2 chance that the medicine would prevent a heart attack in you" or "a 1 in 100 chance that the medicine would prevent a heart attack in you."
At the beginning of each of the first four sections, we asked the patients how worried they were about getting cancer, having a heart attack, having a stroke, or having a hip fracture, respectively. We recorded their responses on a 5-point Likert scale.
In the fifth section, we asked demographic information, determined whether they were aware of having certain risk factors for cardiovascular disease (e.g., smoking, diabetes, cholesterol problems), and asked two general questions about their perceived quality of health and quality of life.
To test the reproducibility of the questionnaire, we repeated the interview for 30 patients 2 months after the initial interview. We considered responses concordant if they were the same in each interview or if the responses differed by one threshold in either direction. For example, a patient whose threshold was 1 in 50 in the first interview had a concordant response if his or her threshold was 1 in 20, 1 in 50, or 1 in 100 in the second interview. The concordance rate for all of the questions regarding thresholds was 80%.
We used the SAS software system (17) to analyze the data. We analyzed continuous variables with Student's t test and categorical variables with the chi-square test. We used a linear trend for proportions to analyze the cancer screening preferences. Because each patient responded for each test complexity, we used a matched design according to the methods of Fleiss (18). We analyzed the medication preferences by McNemar's test for paired dichotomous data (18).
Within each of the hypothetical medical conditions, we addressed the multiple testing issue through use of the Bonferroni adjustment (19) based on the number of comparisons made within that condition (four for screening and six for prevention). For cancer screening preferences and medication preferences, statistical significance was assumed for p < .0125 and p < .0083, respectively.
| Results |
|---|
|
|
|---|
Fig. 1 illustrates their thresholds for cancer screening and shows a clear association between likelihood of detection and preference for screening (p < .001). The percentage of seniors opting for a screening test increased as the likelihood of detection increased. As expected, the complexity and cost of the screening test influence the threshold at which seniors thought screening was worthwhile. Of note is the percentage of seniors at either extreme of the scale. Some seniors (13%) would want cancer screening even if the likelihood of detection was remote (i.e., 1 in 10,000). On the other hand, some seniors (18%) would not want a screening test even if the likelihood of detection was high (i.e., 1 in 10).
|
|
| Discussion |
|---|
|
|
|---|
The presentation of statistical data can significantly influence providers (20)(21)(22)(23)(24) and patients' (15)(25)(26)(27) preferences for treatment. Relative risk reduction, or the degree to which an intervention diminishes the risk of a disease, is insignificant without a comprehension of the baseline incidence risk for that disease. The absolute risk reduction relates the benefit of the intervention to the baseline risk, thereby providing a more realistic idea of the real size of the benefit to a patient (12). Unfortunately, many providers do not discuss risk reduction in quantitative terms that patients understand (28)(29). Quite possibly, many providers do not grasp the difference between absolute and relative risk-reduction and, furthermore, are unfamiliar with the risk-reduction statistics for many screening and preventive medication therapies.
This study indicates that when seniors are presented with absolute risk-reduction information, their treatment preferences may differ from the standardized screening recommendations espoused by professional societies. For example, mammography, which will detect breast cancer in 1 of every 125 older women screened, could be considered complex (i.e., it requires an extra appointment and some discomfort) and costly (30)(31). When offered a complex, costly cancer screening test with a detection rate of 1 in 100, 4862% of seniors would decline the procedure. We recognize that a patient's response to the probability of detecting cancer may be different than his or her response to the probability of preventing morbidity or mortality. Utilizing the number needed to screen to prevent one premature cancer death, which varies for mammography from 1700 to 68,000, might have provided patients with a better idea of the likelihood that the intervention would benefit them individually (12)(32)(33)(34)(35). Nevertheless, the fact that about half of our respondents would decline cancer screening at a threshold similar to the detection rate for mammography indicates the importance of eliciting patient preferences before proceeding with screening.
Antihypertensives are the most widely prescribed medicines in geriatrics. Treating hypertension with medications has a 1 in 50 to a 1 in 20 chance of preventing strokes in seniors (i.e., a 25% absolute risk reduction) (36)(37)(38). When considering inexpensive medications associated with an absolute risk reduction for stroke of 25%, 4151% of our respondents would decline such medications, while 5465% would decline a costly medication. Similar responses occurred for cholesterol-lowering agents to prevent myocardial infarctions, which have a 1 in 100 to a 1 in 20 chance of preventing myocardial infarction in seniors, depending on premorbid status (39)(40)(41).
The absolute risk reduction associated with estrogen replacement therapy may be 12% (42)(43)(44)(45)(46)(47). When seniors consider this likelihood of benefit, 7078% (depending on cost) would decline.
Medical decision making is certainly more complex than simply considering probabilities, in this case cancer detection rates and absolute risk reductions. Dolan and Bordley have presented a decision-making model that considers the major components of decision making in ambulatory care, including risk reduction, avoiding side effects, minimizing out-of-pocket costs, and avoiding hassles (48). Based on our experience in the pilot study, in which consideration of side effects seemed to unduly bias patients against medication use, we excluded this component from our study. The reality is that treatment of hypertension, for example, rarely needs to involve long-term side effects because we have so many treatment options.
Other factors impacting medical decision making that we did not explore in this study include belief in certain diagnostics (consider, for example, the controversy over mammography for women age 40 to 49 (49)(50)(51)(52)), belief in certain therapeutics (53), emotion (54), burden on family, association with close friends and relatives who have had particular diagnoses, expected quality of life (55), expected symptoms (53), competing risks (56), and cost to society. Our exploration of factors such as fear about a particular disease, awareness of risk factors, perceived quality of life, and perceived quality of health was cursory and did not result in any correlation between these factors and the preventive intervention about which we asked.
Our results from this study and from a previous study to determine preferences for cardiopulmonary resuscitation (57) suggest that probability of benefit is an important factor for seniors to make informed decisions about their medical care. This study, however, has several important limitations.
First, the proposed preventive interventions were hypothetical and nonspecific. Had we solicited patient preferences for distinct, well-known cancer screening tests (e.g., mammography) or preventive medications (e.g., aspirin to prevent myocardial infarction), their responses may have differed. Future inquiry into seniors' preferences for specific preventive interventions with known indications, costs, side effects, and absolute risk reductions would be highly beneficial to the practitioner in terms of anticipating the likelihood that a patient would be willing to accept the intervention.
Second, the survey did not evaluate the actual risk factors or disease states of our patients, nor did we correlate such information with their preference for corresponding preventive interventions. If, for example, we had asked the questions to a control group and a group of patients with hypertension who were already taking antihypertensive medications, the responses between the two groups probably would have differed. The effect of patients' risk factors or disease states on their preference for preventive interventions needs more exploration.
Third, our results came from seniors who were not acutely ill, had well-established relationships with their physicians, and were predominantly of one ethnicity (78% Caucasian). The conclusions may not be generalizable to other populations.
Fourth, we may have created a framing bias with the use of terms such as, "a simple blood test," "a test requiring an extra appointment and some discomfort," and "put a strain on the pocketbook that month." Additionally, answer choices for the survey were limited to a few specific risk-reduction percentages. Rather than spontaneously generating their own threshold for risk reduction for a particular intervention, respondents had to choose from prescribed percentages, which precluded an in-depth linear regression analysis of patient-generated thresholds at which preference for therapy rapidly diminished. Future work could determine if there are threshold probabilities of prevention that lead to optimal interest in the intervention.
Finally, we did not specify the frequency of cancer screening or the duration of medication use in our hypothetical questions. When considering cancer screening, our patients may have assumed one-time screening, or they may have assumed repeated screening over many years. Similarly, when considering medication use, they may have assumed limited duration of treatment (e.g., 1 year), or they may have assumed prolonged duration (e.g., 10 to 20 years). This factor could have contributed to some of the variability in patient responses.
Despite these limitations, we conclude that seniors are responsive to probability of benefit, expressed in absolute numbers, that such probabilities correlate with interest in the intervention, and that there is a diversity of preferences at each probability threshold, which necessitates individualized care. Absolute risk benefit is a key element in medical decision making with seniors.
Our results have encouraged us to learn better ways to communicate benefits and burdens to our patients. Expressing absolute risk reduction with simple percentages has been effective and easy to follow for clinicians and patients. In doing so, we have found significant variation in how seniors value risk reduction. We have also found that the preferences of a majority of our oldest patients are not consistent with many clinical guidelines (e.g., yearly mammograms with no upper age limit) espoused by professional societies. Our study suggests that, if clinical guidelines are to be pertinent and useful to our patients, professionals must obtain patient input in preventive treatment decisions.
| Acknowledgments |
|---|
Received July 24, 2000
Accepted April 16, 2001
| References |
|---|
|
|
|---|
This article has been cited by other articles:
![]() |
S. J. Cutler and L. G. Hodgson To test or not to test: Interest in genetic testing for Alzheimer's disease among middle-aged adults American Journal of Alzheimer's Disease and Other Dementias, January 1, 2003; 18(1): 9 - 20. [Abstract] [PDF] |
||||
![]() |
J. E. Morley Editorial: Hot Topics in Geriatrics J. Gerontol. A Biol. Sci. Med. Sci., January 1, 2003; 58(1): M30 - 36. [Full Text] [PDF] |
||||
| ||||||||||||||||||||||||||||||||
| HOME | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|---|