A decision model and cost-effectiveness analysis of colorectal cancer screening and surveillance guidelines for average-risk adults

OBJECTIVES: Guidelines for colorectal cancer screening and surveillance in people at average risk and at increased risk have recently been published by the American Gastroenterological Association. The guidelines for the population at average risk were evaluated using cost-effectiveness analyses. METHODS: Since colorectal cancers primarily arise from precancerous adenomas, a state transition model of disease progression from adenomatous polyps was developed. Rather than assuming that polyps turn to cancer after a fixed interval (dwell time), such transitions were modeled to occur as an exponential function of the age of the polyps. Screening strategies included periodic fecal occult blood test, flexible sigmoidoscopy, double-contrast barium enema, and colonoscopy. Screening costs in 1994 dollars were estimated using Medicare and private claims data, and clinical parameters were based upon published studies. RESULTS: Cost per life-year saved was $12,636 for flexible sigmoidoscopy every 5 years and $14,394 for annual fecal occult blood testing. The assumption made for polyp dwell time critically affected the attractiveness of alternative screening strategies. CONCLUSIONS: Sigmoidoscopy every 5 years and annual fecal blood testing were the two most cost-effective strategies, but with low compliance, occult blood testing was less cost-effective. Lowering colonoscopy costs greatly improved the cost-effectiveness of colonoscopy every 10 years.     

The influence of waiting times on cost-effectiveness: a case study of colorectal cancer mass screening

When a cost-effectiveness analysis is implemented, the health-care system is usually assumed to adjust smoothly to the proposed new strategy. However, technological innovations in health care may often induce friction in the organization of care supply, implying the congestion of services and subsequent waiting times. Our objective here is to measure how these short run rigidities can challenge cost-effectiveness recommendations favorable to an innovative mass screening test for colorectal cancer. Using Markov modeling, we compare the standard Guaiac fecal occult blood test (gFOBT) with an innovative screening test for colorectal cancer, namely the immunological fecal occult blood test (iFOBT). Waiting time can occur between a positive screening test and the subsequent confirmation colonoscopy. Five scenarios are considered for iFOBT: no further waiting time compared with gFOBT, twice as much waiting time for a period of 5 or 10 years, and twice as much waiting time for a period of 5 or 10 years combined with a 25 % decrease in participation to confirmation colonoscopies. According to our modeling, compared with gFOBT, iFOBT would approximately double colonoscopy demand. Probabilistic sensitivity analysis enables concluding that the waiting time significantly increases the uncertainty surrounding recommendations favorable to iFOBT if it induces a decrease in the adherence rate for confirmation colonoscopy.     

Randomized controlled trial of a patient decision aid for colorectal cancer screening.

PURPOSE: To conduct a pilot test of a decision aid designed to help patients choose among currently recommended colorectal cancer screening programs. METHODS: Randomized controlled trial comparing a patient decision aid based on multicriteria decision-making theory with a simple educational intervention. PATIENT POPULATION: 96 patients at average risk for colorectal cancer seen in an Internal Medicine practice in Rochester, New York. OUTCOME MEASURES: The two primary outcome measures were patient decision process and the decision outcome. Patient decision process was assessed using the decisional conflict scale. Decision outcome was defined as the proportion of colorectal cancer screening plans carried out. RESULTS: After controlling for the effects of the physicians in a factorial analysis of variance, patients who used the decision aid had lower decisional conflict regarding colorectal cancer screening decisions (F ratio 6.47, P = 0.01) due to increased knowledge, better clarity of values, and higher ratings of the quality of the decisions they made. There was no difference between the groups in decision outcomes: 52% of patients in the control group and 49% in the experimental group completed planned screening tests (P = 1.0). CONCLUSIONS: In a pilot study, a multicriteria-based patient decision aid for colorectal cancer screening improved patients' decision-making processes but had no effect on the implementation of screening plans.     

Trials of decision aids for prostate cancer screening: a systematic review

BACKGROUND: Patient decision aids are used to promote informed decision making. This review examines the methods and findings of studies that have evaluated the impact of prostate cancer screening decision aids on patient outcomes. METHODS: MEDLINE, the Cochrane Registry, reference lists, and abstracts from professional meetings were searched through December 2006. Search terms included prostate cancer screening and decision making. Studies were included if a patient education intervention for prostate cancer screening had been evaluated against a control condition. RESULTS: Eighteen eligible trials, involving 6221 participants, were identified. Sixteen studies enrolled primary care patients, while the remaining two studies were community-based. All the prostate cancer screening decision aids were in English, with varied reading levels. Consistent with previous reviews, the patient decision aids improved patient knowledge and made patients more confident about their decisions. The aids appeared to decrease interest in prostate-specific antigen testing and screening behavior among patients seeking routine care (relative risk [RR]=0.88, 95% confidence interval [CI]=0.81-0.97, p=0.008); the aids had no impact on the screening behavior of patients seeking screening services. Additionally, patients who received patient decision aids were more likely to prefer watchful waiting as a treatment option if they were found to have prostate cancer than were controls (RR=1.53, 95% CI=1.31-1.77, p<0.001). CONCLUSIONS: Prostate cancer screening decision aids enhance patient knowledge, decrease decisional conflict, and promote greater involvement in decision making. The absence of outcome measures that reflect all elements of informed decision making continues to limit the field.     

Breast cancer screening. A study in cost-effectiveness analysis

This paper identifies the long run average British National Health Service screening costs in one particular screening clinic for various different regimes: mammography, thermography and clinical examination; thermography and clinical examination; and mammography and clinical examination; each of these having one or two clinical examinations and the option of single or double reporting of mammograms and thermograms. It then compares the cost-effectiveness of these different regimes where 'costs' are defined widely to include not only screening costs but also biopsy costs, anxiety costs for women biopsied, costs of false negatives, etc. By defining costs in this way, it was possible (if somewhat tentatively because of the small numbers involved) to identify mammography with single reporting together with a single clinical examination as 'the best buy'.     

Evidence-based consumer choice: a case study in colorectal cancer screening

OBJECTIVES: To elicit community preferences for colorectal cancer (CRC) screening by faecal occult blood test (FOBT) using discrete choice modeling (DCM). To provide policymakers with information that would assist them in designing the future national screening program. METHODS: 301 participants in central Sydney, aged 50 to 70 years, at 'average' risk of CRC, participated in a face-to-face discrete choice study interview in which screening profiles were posed to derive estimates for preferences for CRC FOBT screening. RESULTS: Three characteristics were varied in our screening profiles, namely: benefit (CRC deaths prevented); potential harm (false positive induced colonoscopy); and notification policy (of test result). Ninety-four respondents (32%) did not trade off CRC deaths prevented for any reduction in harms. Twelve per cent always chose no screening. The remaining 56% traded benefits and harms. These latter respondents (n = 164) were willing to accept 853 (false positive induced) colonoscopies for one CRC death prevented. CONCLUSIONS: While survival was all that mattered for just over one-third of the sample and 12% would choose no screening, the remaining individuals were prepared to trade CRC deaths prevented against other characteristics. CRC screening will not receive unqualified community support, irrespective of harms. IMPLICATIONS: In any future national CRC screening program, consideration of these insights about community assessment of benefits, harms, costs and other characteristics of CRC screening is warranted.     

Patient decision aids to support clinical decision making: evaluating the decision or the outcomes of the decision.

Decision aids (DAs) are tools to support patients make informed health decisions with their practitioner. They aim to improve patient knowledge of options, incorporate patient preferences and values, and increase patient involvement in health decision making. Increasingly, the debate about DAs concerns how they should be implemented in practice, with the view that DAs are superior to usual clinical care in facilitating health decisions. The authors challenge this view and suggest that DA research has focused on measures of decision process, leaving the effects on the outcome of the decision relatively unknown. It is still unclear in which conditions DAs are better for patient health and well-being than clinician-led decisions. The authors present a new randomized design to examine the effects of DA-supported patient choice on patient-centered outcomes to identify where DAs are best implemented in clinical practice. In this design, patients are randomized to 1 of 4 arms: intervention A, intervention B, choice of either intervention supported by a clinician, or choice of either intervention supported by a decision aid. Health and quality of life measured over the long term are presented as the primary outcomes. The authors propose that this design will allow the proper assessment of different modes of decision making.     

Risk assessment and clinical decision making for colorectal cancer screening

Background

Shared decision making (SDM) related to test preference has been advocated as a potentially effective strategy for increasing adherence to colorectal cancer (CRC) screening, yet primary care providers (PCPs) are often reluctant to comply with patient preferences if they differ from their own. Risk stratification advanced colorectal neoplasia (ACN) provides a rational strategy for reconciling these differences.

Objective

To assess the importance of risk stratification in PCP decision making related to test preference for average‐risk patients and receptivity to use of an electronic risk assessment tool for ACN to facilitate SDM.

Design

Mixed methods, including qualitative key informant interviews and a cross‐sectional survey.

Participants

PCPs at an urban, academic safety‐net institution.

Main Measures

Screening preferences, factors influencing patient recommendations and receptivity to use of a risk stratification tool.

Key Results

Nine PCPs participated in interviews and 57 completed the survey. Despite an overwhelming preference for colonoscopy by 95% of respondents, patient risk (67%) and patient preferences (63%) were more influential in their decision making than patient comorbidities (31%; P < 0.001). Age was the single most influential risk factor (excluding family history), with <20% of respondents choosing factors other than age. Most respondents reported that they would be likely to use a risk stratification tool in their practice either ‘often’ (43%) or sometimes (53%).

Conclusions

Risk stratification was perceived to be important in clinical decision making, yet few providers considered risk factors other than age for average‐risk patients. Providers were receptive to the use of a risk assessment tool for ACN when recommending an appropriate screening test for select patients.     

Provider perspectives on the utility of a colorectal cancer screening decision aid for facilitating shared decision making

Background Decision aids for colorectal cancer (CRC) screening have been shown to enable patients to identify a preferred screening option, but the extent to which such tools facilitate shared decision making (SDM) from the perspective of the provider is less well established. Objective Our goal was to elicit provider feedback regarding the impact of a CRC screening decision aid on SDM in the primary care setting. Methods Cross‐sectional survey. Participants Primary care providers participating in a clinical trial evaluating the impact of a novel CRC screening decision aid on SDM and adherence. Main outcomes Perceptions of the impact of the tool on decision‐making and implementation issues. Results Twenty‐nine of 42 (71%) eligible providers responded, including 27 internists and two nurse practitioners. The majority (>60%) felt that use of the tool complimented their usual approach, increased patient knowledge, helped patients identify a preferred screening option, improved the quality of decision making, saved time and increased patients’ desire to get screened. Respondents were more neutral is their assessment of whether the tool improved the overall quality of the patient visit or patient satisfaction. Fewer than 50% felt that the tool would be easy to implement into their practices or that it would be widely used by their colleagues. Conclusion Decision aids for CRC screening can improve the quality and efficiency of SDM from the provider perspective but future use is likely to depend on the extent to which barriers to implementation can be addressed.     

The cost-effectiveness of neonatal screening for Cystic Fibrosis: an analysis of alternative scenarios using a decision model

Objectives

From a health care provider prospective, to assess the cost-effectiveness of four Antiretroviral therapy (ART) regimens given in addition to voluntary counselling and testing (VCT) for preventing mother-to-child transmission of HIV: a) Zidovudine (AZT); b) Nevirapine (NVP); c) a combination of AZT for early antenatal attenders and NVP for late arrivals; and d) combined administration of AZT and NVP and to assess the incremental cost-effectiveness of adding a second VCT session in late pregnancy.

Design & Setting

We examine a hypothetical cohort of 100,000 pregnancies as a decision model. Cost and outcome parameters are estimated as they would apply under Thai routine health service conditions. Effectiveness probabilities are based on best available evidence, from systematic reviews where possible. The main outcome is the number of cases of paediatric HIV averted.

Results

The combining administration of AZT and NVP is the most cost-effective drug option. One VCT session with AZT+NVP averts 337 cases of infection at 556 USD per case averted, while two VCT with the same drug regimen averts 16 additional cases at cost of 1,266 USD per infection averted. The incremental cost-effectiveness ratio of moving from 1VCT, AZT+NVP to 2VCT, AZT+NVP is 16,000 USD per additional averted case, which is much lower than the recommended threshold value for HIV infection averted in Thailand. Multivariate uncertainty analysis supports the findings, showing that at a threshold of 35,000 USD, 2VCT, AZT+NVP is preferable to other VCT and drug strategies.

Conclusion

Interventions for preventing mother-to-child transmission of HIV are cost-effective. Further costs and negative effects of drug resistance, are unlikely to outweigh the social benefits of reduce transmission of HIV. This model suggests that the new drug regimen is a cost-effective option in the Thai health system at currently accepted thresholds for adopting health technologies.     

A proposal for the development of national certification standards for patient decision aids in the US

Efforts to implement the use of patient decision aids to stimulate shared decision making are gaining prominence. Patient decision aids have been designed to help patients participate in making specific choices among health care options. Because these tools clearly influence decisions, poor quality, inaccurate or unbalanced presentations or misleading tools are a risk to patients. As payer interest in these tools increases, so does the risk that patients are harmed by the use of tools that are described as patient decision aids yet fail to meet established standards. To address this problem, the National Quality Forum (NQF) in the USA convened a multi-stakeholder expert panel in 2016 to propose national standards for a patient decision aid certification process. In 2017, NQF established an Action Team to foster shared decision making, and to call for a national certification process as one recommendation among others to stimulate improvement. A persistent barrier to the setup of a national patient decision aids certification process is the lack of a sustainable financial model to support the work.     

Toward the 'tipping point': decision aids and informed patient choice

Preference-sensitive treatment decisions involve making value trade-offs between benefits and harms that should depend on informed patient choice. There is strong evidence that patient decision aids not only improve decision quality but also prevent the overuse of options that informed patients do not value. This paper discusses progress in implementing decision aids and the policy prospects for reaching a "tipping point" in the adoption of "informed patient choice" as a standard of practice.     

Informed choice in bowel cancer screening: a qualitative study to explore how adults with lower education use decision aids

Background Offering informed choice in screening is increasingly advocated, but little is known about how evidence‐based information about the benefits and harms of screening influences understanding and participation in screening. Objective We aimed to explore how a bowel cancer screening decision aid influenced decision making and screening behaviour among adults with lower education and literacy. Methods Twenty‐one men and women aged 55–64 years with lower education levels were interviewed about using a decision aid to make their screening decision. Participants were purposively selected to include those who had and had not made an informed choice. Results Understanding the purpose of the decision aid was an important factor in whether participants made an informed choice about screening. Participants varied in how they understood and integrated quantitative risk information about the benefits and harms of screening into their decision making; some read it carefully and used it to justify their screening decision, whereas others dismissed it because they were sceptical of it or lacked confidence in their own numeracy ability. Participants’ prior knowledge and beliefs about screening influenced how they made sense of the information. Discussion and conclusions Participants valued information that offered them a choice in a non‐directive way, but were concerned that it would deter people from screening. Healthcare providers need to be aware that people respond to screening information in diverse ways involving a range of literacy skills and cognitive processes.     

A cost-effectiveness analysis of cervical cancer screening: health policy implications

This paper presents a framework for comparison of screening programme designs, based on efficiency and cost effectiveness criteria. The design parameters, such as choice of screening interval, which population segments to screen and expected participation rates in the selected population segments, are varied simultaneously. The costs and effects for a range of existing and hypothetical screening programmes against cervical cancer are estimated, using a mathematical simulation model. On the basis of these estimates average costs per life year and marginal costs per life year are calculated for a range of programmes. These calculations result in the definition of a range of inefficient programmes. Moreover, it is illustrated that the cost effectiveness of the efficient screening programmes decreases at an increasing rate as programmes are intensified either by way of shortening the screening interval or extending the target population segment to encompass the very young and/or the very old. The conclusion of this paper is that one should probably not extend screening programmes against cervical cancer beyond screening women in the age group 25-59 years every 4 years. In addition, increasing the participation rate of this group is a more cost effective way of increasing the number of life years gained, rather than extending the target group or decreasing the screening interval.