Cancer and cardiovascular diseases (CVDs) are the leading causes of mortality worldwide and of particularly insidious character when it comes to timely discovery. Cancerous conditions are usually difficult to detect unless they are already causing issues. The same could be said for CVDs, although some can be detected in time by an experienced physician with proper tools at their disposal. Peripheral arterial disease or PAD is one such example. Yet despite its importance in overall cardiovascular health, many physicians are still unequipped to diagnose PAD in their patients properly.
In this blog you will learn:
- Epidemiology of PAD.
- PAD awareness.
- Screening shortcomings.
- Diagnosis follies.
- Analysis and possible solutions.
How common is PAD (worldwide and in Australia)?
Worldwide prevalence of PAD was estimated to be 237 million adults in 2015, up from 202 million in 2010, and is expected to continue to rise [1, 2]. The main reasons for this are the rising number of people with diabetes and other risk factors, including non-modifiable ones like old age [3-6]. Stratification across regions and countries varies considerably: The Western Pacific Region has the most cases whereas the Eastern Mediterranean Region has the fewest .
In Australia specifically, it is estimated that at least 15.6% of inhabitants have PAD and that most of them are asymptomatic [7, 8]. Why highlight Australia? It was the site of a comprehensive cross-sectional study about barriers preventing effective screening and diagnosis of PAD by general practitioners (GPs). The study was conducted between September 2011 and March 2012 and encompassed 1120 GPs in the state of Queensland , which lies in the region with the highest average prevalence of PAD.
What do doctors know about PAD?
The researchers who conducted the study sent GPs a questionnaire with 26 questions arranged in four sections (GP demographics, PAD awareness, screening, and diagnosis) . Of those 1120, only 287 (26%) responded; 55 were additionally excluded since they reported not consulting with PAD patients, leaving 232 individuals who were included in the analysis . The results were telling, starting with GPs’ estimates about prevalence, morbidity, and mortality.
Nearly half (45%) of GPs estimated the prevalence of PAD among patients over 55 years to be between 10% and 20%, while a quarter of them estimated it to be in the ballpark of 20% to 30% . Various population-based studies published a wide range of estimates, from 6% to 18%, meaning that the considerable portion of GPs were correct . The majority (62%) of them also correctly estimated that at least 40% of patients are asymptomatic [9, 11, 12].
Their estimates of likelihood of amputation in severe cases of PAD and cardiovascular mortality in patients with the disease were less accurate . Moreover, they estimated the asymptomatic form of the disease to be less dangerous than the symptomatic . However, most worrisome was their sporadic use of accurate diagnostic methods.
How do doctors screen for PAD?
There are several established screening methods for PAD, ranging from a simple questionnaire to CT or MRI angiography [13, 14, 15]. The most convenient, inexpensive, and recommended method is an ABI (Ankle-Brachial Index) assessment, particularly if performed with an automated oscillometric-plethysmographic diagnostic device, which eliminates user errors [16, 17, 18].
Of the surveyed GPs, only barely more than half (54%) used ABI; the vast majority (98%) assessed the likelihood of PAD only on the basis of medical history (e.g. smoking or type 2 diabetes) and examination . Physical examination is unreliable, particularly if performed by a less-experienced examiner . Despite this, an astonishing 27% of them screened only using history and examination . Additionally, only 6% of GPs knew about evidence-based guidelines related to PAD screening .
Now for the reasons for this situation (in GPs own words); the majority (more than two thirds) answered that time limitations and equipment availability were the main reasons, followed by staff availability (51%), lack of reimbursement (43%) and cost (42%) . The skills (24%) and knowledge (25%) required to perform the screening were deemed the least problematic .
Are PAD diagnoses accurate?
Sporadic use of reliable screening methods was also evident in answers related to diagnosis of PAD. History and examination were the main go-to methods (as answered by 90% and 84% of GPs, respectively), followed by ABI assessment, which was used by only 62% of questionnaire respondents . Researchers also found that younger doctors were more likely to use the ABI than their older colleagues .
The reasons were similar: equipment availability (60%) and time limitations (55%) with lack of training and staff availability in third (55 %) and fourth (51 %) place respectively . In other words, comparatively easy to resolve, at least when it comes to proper equipment.
How can low screening rates be resolved?
And how do Australian GPs fare from the perspective of PAD diagnosis and screening in comparison with their colleagues elsewhere? With one third of them screening based on ABI, they are ahead of their Swiss colleagues of whom only 20% can make that claim . However, their opinions on the main obstacles are somewhat in contrast with doctors in the United States, whose only concern was time limitation and not equipment availability .
Possible solution(s): improve the time allocated to each patient, although for the near future that seems impossible . The next potential solution is the wider introduction of automated oscillometric-plethysmographic diagnostic devices in general practice coupled with a practical educational intervention [21, 22].
The most prominent barriers to reliable and accurate screening and diagnosis of PAD are generally time limitation and lack of proper equipment, both maintainable using an ABI assessment performed by an oscillometric-plethysmographic diagnostic device.