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The-cost-of-delayed-PAD-diagnosis

The diagnosis and treatment of virtually any disease should be prompt and comprehensive, especially if it is of cardiovascular nature. This should come as no surprise given the potential deleterious effects of cardiac issues on the entire health and well-being, yet there are also a number of vascular conditions which, if diagnosed late (or not at all), can have serious and even terminal consequences for the affected individual. One of the most prominent of those is peripheral artery disease (PAD).

Delayed diagnosis of PAD (also known as lower extremity artery disease or LEAD for short) is additionally associated with significant healthcare costs, both from a manpower and financial perspective. This is particularly worrisome not only due to the fact that PAD is linked with increased risk of general cardiovascular morbidity and mortality, but also the rising prevalence of the disease itself. There were an estimated 236.62 million patients with PAD in 2015 alone, up from 202 million in 2010 – in the same time period, the number of diabetics went from 285 million in 2010 to 415 million in 2015 [1, 2, 3, 4]. Any correlation between the two is not coincidental since diabetes mellitus (type 1 and 2) is one of the most significant risk factors for PAD [5]. It is projected that the worldwide number of individuals with diabetes will reach 693 million and it is highly likely the numbers of those with PAD will as well, unless there is a significant advancement in the prevention and treatment of either disease [6, 7].

Fortunately, diagnosis of PAD is easy and accurate with the right diagnostic tools as is treatment in the initial stages of the disease, when it can be managed with conservative methods, but can quickly become very expensive and complex if the disease is already at an advanced stage and is associated with comorbidities (a frequent occurrence). On the other hand, despite their availability and comparative low cost, diagnostic tools such as ABI (Ankle-Brachial Index) assessment are often underutilised, even in patients in risk groups (for PAD). A study conducted in the UK on the utilisation of ABI assessment in patients with chronic wounds found that 40% of patients had not received an assessment or it was unclear whether a recording had been taken and [8]. Additionally, it was discovered that nearly 31% of patients with venous leg ulcers involved in the study were not receiving the necessary compression therapy (a staple conservative treatment method) [8].

(Un)necessary costs?

Some of the reasons for underutilisation of ABI assessment in primary care, where it is most needed (preventive screening of at-risk patients), are supposedly the time needed to perform the ABI, staff constraints and lack of reimbursement (in specific healthcare systems) [9]. However, we could also pin that to the often-asymptomatic nature of PAD (only 10% of patients are symptomatic, 40% of them are entirely asymptomatic and the rest have atypical symptoms) and lack of knowledge of risk factors [10, 11].

Regardless of the exact cause of the lack of use of ABI assessment or other diagnostic/screening methods, the data regarding the cost-effectiveness of their use in primary case, particularly the ABI, is undisputable. A comprehensive study conducted in the Netherlands on the cost-effectiveness of PAD screening with ABI and subsequent preventive treatment (low doses of aspirin or clopidogrel) in individuals at high risk of acute cardiovascular events from the Dutch societal perspective is one source of such data [12].

Using the Markov model (hypothetical population consisting of asymptomatic males and females aged 55 years with at least one risk factor for PAD), they found statistically significant differences in health outcomes and associated costs between the ABI screening and treatment group and individuals who weren’t beneficiaries of either [12]. For the first group life years and QALYs gained were 21.79 and 15.66 respectively at a (lifetime) cost of €26,548, while for the second one (no screening and treatment) they were 20.69 life years and 15.58 QALYs at a cost of €28,052 — a difference of €1503 [12]. In some simulated scenarios the difference was even higher: from €1783 and €3611 all the way up to €4039 [12]. The study also highlighted that the cost effectiveness acceptability curves show 88% probability of PAD screening being cost effective (at the willingness to pay threshold of €40,000) [12].

A comparable study, by researchers in the United States, came to similar conclusions. Again using the Markov model, but based on a different (65-year-old patients) population, they found that the optimal age (of the patient) for screening for (asymptomatic) PAD was between 55 and 65 years [13]. Additionally, the cost-effectiveness was greatest in high-risk patients (e.g. tobacco users) [13]. However, in spite of these findings and the fact that an ABI measurement is recognised as a biomarker of cardiovascular disease risk (in asymptomatic individuals) the United States Preventive Services Task Force (USPSTF), an expert panel funded by United States Department of Health & Human Services (HHS), gave the routine screening for PAD a “D” grade (i.e. recommended against the screening) [14, 15].

The detrimental effects of delayed diagnosis and undertreatment or even no treatment of PAD are likewise well researched. A cohort study conducted in France compared a group of 5889 patients, between 2007 and 2011, diagnosed with PAD with at least one other atherosclerotic diseases (aorta, generalised or unspecified ) with a control group with no diagnosis of PAD, [16].

The results were telling: total annual management costs were €14,949 in the PAD group and €3,812 in the control group – the attributable annual cost of PAD is therefore €11,137 [16]. Researchers have also noted that 48.9% of studied patients were receiving a statin plus an antiplatelet or anticoagulant drug, but only 31.6% of them were also receiving an ACE inhibitor or angiotensin II receptor blocker — such undertreatment, of course, translates to higher rates of adverse events and mortality for PAD patients in France [16]. Their findings were supported by result comparison with the Cohorte des Patients Artériopathes (COPART), Reduction of Atherothrombosis for Continued Health (REACH) and Swedish studies [17, 18, 19].

Bottom line: targeted screening of at-risk individuals and consequent (if they are diagnosed with PAD) secondary prevention of cardiovascular events by anti-platelet medication (e.g. aspirin and clopidogrel) is cost effective and results in significant health gain by reducing cardiovascular events and amputations in those patients.

Screening for PAD on the basis of the ABI assessment, particularly in high-risk patients, is associated with significant cost reductions and gains in quality-adjusted life-years.