Solid reasons to equitably screen

Abstract

Preventive care can address inequities, or avoidable disparities in health outcomes. Preventive care, including screening for cardiovascular disease and cancer, and health promotion including offering counselling and preventive treatments, remains a routine part of primary care for good reasons. Here, we provide a fresh perspective on preventive care that focuses on health equity and we explain how centering on health equity can bring into focus the demonstrated benefits of screening in the context of other primary care interventions, the importance of patient preferences, and the relative magnitude of screening harms. Informed patients often prefer screening, and this should be offered where reasonable and the potential implications of negative screening recommendations for health equity should be carefully considered. The evidence for screening is better than the evidence of many other routine and uncontroversial aspects of care and the downsides of screening are sometimes overstated.

INTRODUCTION

Preventive care, including screening for cardiovascular disease and cancer, and health promotion, including offering counselling and preventive treatments, remain routine parts of primary care for very good reason despite some skepticism, specific controversies and prominent opposition. Indeed, preventive care topics, such as breast cancer screening, are among the most contentious clinical issues with a history of vigorous debate and even litigation over what the studies show and who should be screened (Independent UK Panel on Breast Cancer Screening, 2012).

In this commentary paper, we provide a fresh perspective on preventive care that focuses on health equity. The purpose of this article is to explain how centering on health equity can bring into focus the demonstrated benefits of screening in the context of other primary care interventions, the importance of patient preferences, and the relative magnitude of screening harms (Persaud et al., 2023). New priorities for preventive care research and future guidance appear when fairness is foregrounded. Some hotly contested issues seem to fade away when the focus is equity.

PREVENTIVE CARE AND SCREENING SAVE LIVES

Preventive care saves lives. A meta-analysis of clinical trials showed that all-cause mortality is 17 % lower among older adults randomly allocated to proactive preventive care outreach by nurses, physicians or other care providers compared with routine primary care (Ploeg et al., 2005). Specific preventive care interventions such as colorectal cancer screening reduce all-cause mortality (Swartz et al., 2017). There is also indirect evidence that preventive care saves lives. Access to primary care is associated with reduced mortality, and this is likely partly due to preventive care and concomitant primary care (Baker et al., 2020). For example, access to primary care increases the likelihood of being screened for hypertension and appropriately treated, which is known to save lives (Banach et al., 2014).

To help achieve fairness in health outcomes, access to life-saving interventions such as preventive care must be equitable (Persaud et al., 2023). This can involve prioritizing people experiencing disadvantages for access to preventive care (Persaud et al., 2023). There are disparities in health outcomes including life expectancy based on racialization, income, functional limitations, and other bases for discrimination (Persaud et al., 2023). Ensuring access to proven preventive care is one way to address health inequities, alongside systemic or upstream policy changes (Persaud et al., 2021).

PATIENTS OFTEN PREFER SCREENING AFTER CONSIDERING THE BENEFITS AND HARMS

Patients generally prefer screening after receiving explanations of its benefits and risks, and this is true across patient populations and screening interventions (Mansfield et al., 2016; Smith et al., 2021). Surprisingly, this preference of patients for screening is sometimes presented as a tendency that clinicians should counter (Thériault et al., 2023). Patients may have valid reasons for wanting effective screening interventions, such as a lack of opportunity to share concerns, but physicians are not necessarily better placed to judge what preventive care patients should receive.

Screening and other preventive care recommendations can determine which patients access care and are essentially different from treatment or management recommendations. Shared decision-making can be used to discuss treatment options with patients with specific conditions such as diabetes or osteoarthritis (Coronado-Vazquez et al., 2019). But even for common conditions such as these, a relatively small number of discussions would be needed when compared with the number of discussions needed to discuss whether or not to screen for conditions like breast cancer or fragility fractures (Grad et al., 2023). The related practical problem with shared decision making applied to screening is that the two alternatives – simply ordering screening or never mentioning screening – will likely take less time than the discussion (whereas for conditions such as diabetes or osteoarthritis, there is no neat resolution).

For some screening interventions, shared decision making about whether to screen would not make sense at all. For example, clinicians would not ask patients if they want to be asked screening questions for depression. It is also unclear that shared decision making will help to address inequities, since discussions of different options will likely play out differently for people who are discriminated against in the healthcare system. If the scrutiny sometimes applied to preventive care interventions was applied to the use of shared decision making for preventive care, the conclusion would be that shared decision making has not been shown to improve health outcomes in preventive care and, thus, the time required is not justified. Taking the patient perspective seriously means offering effective screening interventions, consistent with patient preferences.

PREVENTIVE CARE IS MORE USEFUL THAN OTHER ROUTINELY PROVIDED CARE

Patients with ankle pain who request care are usually not turned away even though this type of care probably does not reduce the overall risk of dying. Yet, the fact that not all screening recommendations have been shown to reduce all-cause mortality is sometimes represented as reason to be skeptical about screening (Thériault et al., 2023). Clinicians generally do not proclaim that they will, as a rule, not help to manage ankle pain but clinicians also do not order an MRI for every ankle sprain. By this analogy, it is reasonable to provide preventive care that is requested within reason, while declining full body MRI requests.

The reality is that some individuals have preferential access to preventive care. Executive physicals for those with high-paying white-collar jobs usually involve comprehensive investigations that are likely beneficial (e.g., blood pressure measurement, mental health assessments), among other questionable ones that may not be either helpful or harmful (e.g., vitamin D measurement) and some that are likely more harmful than helpful (e.g. stress tests in asymptomatic patients) (Korenstein et al., 2019). Equitably offering preventive care is a good use of primary care provider time that can help to promote fairness and build trust with patients and this could involve prioritizing outreach to people experiencing disadvantages (Persaud et al., 2023).

Oncology nurses have an important role to play in ensuring that outreach for preventive care is conducted equitably (Persaud et al., 2023). This can include ensuring patients with a particular cancer diagnosis have appropriate screening for other conditions (e.g., screening for cardiovascular disease in people with multiple myeloma) (Tariman et al., 2016).

DOWNSIDES OF SCREENING IN PERSPECTIVE

The benefits of some preventive care interventions are so clear that the potential harms of screening are of less importance. Examples include colorectal cancer screening and hypertension screening (Persaud et al., 2023; Swartz et al., 2017). For preventive care interventions without proven benefits, the harms are also less important because the screening should not generally be performed regardless of the potential harm. It is most important to consider the harms of screening where there is a small or uncertain benefit or where benefits have not been proven by randomized trial. For example, cervical cancer screening is not proven to be effective based on clinical trials so it is important to consider the potential harms and, fortunately, those harms are relatively rare (Persaud et al., 2023). When considering the potential harms of screening, it is thus important to keep the benefits in mind and the fact that patients generally prefer to be screened after the risks have been explained. Potential harms such as those related to worrying about test results or diagnoses must be placed in context if they need to be considered at all.

Even very accurate screening tests will return a substantial number of false positive results if the condition is rare, and in some situations result in further testing of those who falsely screen positive, such as angiography for those with a positive stress test. Such harms of screening are captured by screening trials. Those screening trials also capture other harm such as those who do have the condition of interest but who do not benefit from treatment. Such overdiagnosis can occur, for example, with slowly growing prostate cancers that may never have important implications for patients. But there is no reason to double-count the harms of overdiagnosis since they are already captured in studies of the effects of screening or in studies of the harm of treatment. Also, the absolute number of individuals importantly affected by overdiagnosis may be quite small (Duffy, 2023).

Estimates of the time needed to perform screening interventions often result in fantastical estimates that could not possibly be true (Johansson et al., 2023). Apparently, clinicians are able to complete preventive care interventions in less time than studies suggest given that primary care providers do not actually spend all their time engaged in screening. Preventive care is not identified as an important determinant of family physician job satisfaction (Malhotra et al., 2018). If preventive care required an inordinate amount of time, primary care providers would have identified this sometimes-repetitive task as something that takes away from the joy of work. On the other hand, primary care providers will, over time, see patients who actually benefit from proven preventive care interventions and this may be part of the reason providers are motivated to screen.

HEALTH EQUITY

Preventive care can address inequities or avoidable disparities in health outcomes (Starfield et al., 2005). Negative recommendations can decrease access to care for those experiencing disadvantages while preserving access to care for those who have the knowledge and agency to request it. In this respect, negative recommendations can undermine efforts to promote health equity. An affluent white patient may be more likely to receive mental health care than a disadvantaged racialized patient, so screening for depression could help to promote equitable access to care (Persaud et al., 2023). Similar reasoning applies to other preventive care interventions. Clinicians have discretion to order assessments such as a referral to gastroenterology for consideration of a colonoscopy that can be used to screen asymptomatic individuals or to assess nonspecific symptoms. Thus, those with better access to care or who are more likely to be aware of and request testing may be more likely to receive it if screening is not recommended. This is the case, for example, for colorectal cancer screening for those aged 40 to 50 years according to some guidelines, and intervention is proven to be effective for individuals in this age range (Persaud et al., 2023).

The basic idea that detecting a condition or risk factor early and intervening can protect health is sound. The cliff analogy helps to illustrate why preventive care is important to promoting health equity (Jones et al., 2009). Just as it is better to prevent people from falling off a cliff than to provide them with care once they hit bottom, preventive care can better promote health equity by preventing heart attacks or strokes amongst those experiencing disadvantages versus providing treatments after a person has suffered an irreversible event that was preventable. The cliff analogy also underscores the importance of moving people away from the edge by addressing upstream determinants of health, some of which can be screened for and addressed in clinical settings. Screening for material deprivation and offering resources has been shown to help families with children. Offering resources including legal advocacy can also help people experiencing intimate partner violence (Persaud et al., 2023).

A FRESH APPROACH TO PREVENTIVE CARE ROOTED IN HEALTH EQUITY

The first priority should be to ensure that everyone has access to basic care. This may involve providing certain preventive care services to those without a primary care provider and also prioritizing access for those who are disadvantaged and under-screened (Persaud et al., 2023). People should be able to access preventive care and information about interventions even if they do not have a primary care provider. We have created a resource at screening.ca that can be used by patients with or without a provider. Primary care providers can also prioritize people experiencing disadvantages for preventive care and related outreach (Persaud et al., 2023).

Although preventive care visits have not been shown to reduce mortality compared with usual care (Krogsbøll et al., 2012), periodic health exams for those with limited access to care should be beneficial given that individual components are proven. A dedicated visit may be the most practicable way to ensure some patients have access to preventive care and the opportunity to discuss their preferences. Screening for depression, for example, may help address some disparities in access to mental health care and to other supports offered through primary care for people who do not have clinical depression (Persaud et al., 2023).

Guidance should focus on who should be offered effective preventive care interventions and how to best reach people being poorly served by the healthcare system. Evidence from screening trials is vital to consider, as is information about inequities such as unfairness in the way care is provided. Guidelines should be produced by panels or groups formed in fair ways that are not discriminatory and not dominated by white people, as many panels still are today (Persaud et al., 2022). Guidance should consider the best and most efficient ways to do outreach for preventive care and how to limit the demands on clinician time, especially for tasks more appropriately done by others such as sending out reminder letters that is done centrally, and such guidance may require further study of the best ways to screen.

Although there are solid reasons to provide preventive care now, further research can help to determine the best way to provide preventive care to those who would benefit the most. Trials of screening usually include a usual care group who may have received the screening intervention itself or related assessments. This usual care would decrease the apparent effects of screening and means that the benefits of screening will likely be greater than in those with limited or no access to primary care. Future research should attempt to delineate who will benefit most from effective screening interventions by focusing on people who have poor access to care including preventive care. The results of such studies may actually be more generally useful than studies of screening in the “general” population. For example, trials of breast cancer screening outreach to disadvantaged populations could help put some controversies to bed. Research on who benefits most from screening can be complemented by research of new screening interventions for important conditions and risk factors. It is also important to ensure proven interventions are incorporated into practice; screening for cervical cancer using cytological smears is still common, although HPV testing which allows self-testing would likely reach more people (Persaud et al., 2023). Indeed, while further research is being done, the highest priority should remain ensuring equitable access to proven interventions right now.