A proposition is advanced that health care around the globe suffers from both underuse (undertreatment and undertesting) and overuse (overtreatment and overtesting) that have persisted for decades. Studies have identified many drivers of suboptimal care, generally classified into three categories: (a) economic incentives affecting clinician behavior; (b) professional knowledge, bias, the uncertainty inherent in clinical decision-making; and (c) failure to include patients to capitalize on the power of human relationships. Nonetheless, these drivers only partially explain the persistence of suboptimal use. In a paper appearing in the September 2023 issue of the Journal of Evaluation in Clinical Practice, an argument is proposed that overuse and underuse of services are an inherent consequence of the nature of the relationship between scientific evidence and decision-making. Evidence about diagnosis or health outcomes exists on the probability continuum (from impossibility to virtual certainty), while decisions are categorical (e.g., treatment is or is not recommended).
For example, risk for heart disease can range from close to zero (young, healthy individuals) to 100% when clinically manifested as myocardial infarction. To help reduce risk of heart disease, the American College of Cardiology and American Heart Association (ACC/AHA) recommend that treatment is warranted if the risk ≥7.5% over 10 years. If the estimated risk is below this threshold, treatment should not be recommended. Doing so would reflect overuse/overtreatment. Conversely, not recommending treatment would constitute underuse/undertreatment. So, why not administer statins at 7.4% (or, 7.3%, 7.2% … 0.01%)? The problem relates to an ancient epistemological puzzle called the Sorites paradox, also known as “little-by-little arguments.” Sorites in the Greek language means heap while paradox reflects challenges in defining clear boundaries between borderline cases of the quantities of interest. At which point does the collection of grains become large enough to be called a heap and small enough to be classified as a few scattered grains of sand? The Sorites paradox abounds. Because clinicians use scientific evidence (that exists on a continuum) but make categorical (yes/no) decisions based on numerical thresholds, the Sorites paradox is unavoidable in practice. A possible approach to a solution is to apply threshold decision models, which the authors discuss.