Chronic kidney disease: a silent epidemic

As part of the chronic noncommunicable diseases of our time, one cannot fail to mention chronic kidney disease (also known by the acronym MRC or, even more widely by the Anglo-American acronym of Chronic Kidney Disease, CKD). CKD is defined clinically, and thus diagnosed in the patient, by the presence of a major reduction in renal function and/or by the abnormal presence of markers of renal damage such as albuminuria, i.e., increased elimination through urine of albumin [1]. Reduced renal function is estimated by eGFR (an acronym for the English estimated Glomerular Filtration Rate), and eGFR values of less than 60 mL/min/1.73 m² are considered, regardless of any other factors such as age and sex of the patient, the cut-off for the diagnosis of CKD. As for albuminuria levels, this is diagnosed in two ways. The first, which is considered the most reliable method, is the measurement of albuminuria made on the 24-hour (24h) urine collection. The second method, on the other hand, is the measurement of albuminuria on the morning urine sample and is referred to as albuminuria/creatininuria ratio or ACR. An 'albuminuria excretion greater than or equal to 30 mg/24h (or 30 mg/g at ACR) is the threshold value for the diagnosis of CKD. It should be pointed out that the sporadic detection of reduced eGFR, or increased albuminuria, may be a chance occurrence, whereas to correctly make the diagnosis of CKD, renal damage must be confirmed after at least 3 months [2]. The importance of CKD lies in the fact that it is associated with an increased risk for any individual to develop serious disease over time. In fact, studies in several countries have shown that patients with CKD, when compared with those without CKD, have a significantly increased risk of developing fatal or nonfatal cardiac damage (coronary artery disease, stroke, heart failure) [3,4]. In addition to increased cardiovascular risk, CKD is considered a risk factor for mortality and progression to end-stage renal failure (also known as End-Stage-Kidney-Disease or ESKD) [5]. ESKD is essentially the most advanced stage of kidney damage

which evolves almost inexorably toward recourse to renal replacement treatment such as dialysis or kidney transplantation and is therefore considered a major event because it drastically changes the patient's quality of life. Such deterioration in quality of life has even been accentuated by the COVID-19 pandemic. In fact, patients in ESKD, particularly those undergoing extracorporeal dialysis treatment, have been shown to be at high risk of contagion by having to deal with constant travel in order to reach hemodialysis centers and thus coming into contact with both other "frail" patients and health care workers who can potentially transmit the virus (http://www.quotidianosanita.it/science-and-pharmaceuticals/article.php?article_id=85324).  Based on these data, it is easy to guess that one of the tasks of public health is to identify CKD patients as early as possible, refer them to the Nephrologist Specialist with the aim of intensifying treatments and reducing as much as possible the patient's risk of going through the mentioned clinical events. However, these data are even more alarming when looking at the global dimension of CKD. The prevalence of CKD in the general population ranges between 6 and 13 percent, a striking figure that is similar to or even higher than the prevalence of type 2 diabetes [6]. This range is truly impressive when one considers that CKD, by itself, is associated with a higher rate of cardiovascular events than the presence of type 2 diabetes alone [3]. The trend in prevalence and incidence of CKD shows an abrupt increase (https://notiziemediche.it/insufficienza-renale/insufficienza-renale-cronica-unepidemia-in-continua-crescita-esperti-italiani-fanno-il-punto-della-situazione/). Indeed, globally, prevalence, incidence and mortality from CKD have increased, almost doubled, in the past two decades, having increased by 87%, 89% and 98%, respectively [7]. In some countries, such as the United States of America, registries showing CKD trends (in terms of prevalence, incidence, stratification for key demographic variables such as age and sex) over the years are now available and freely accessible (https://adr.usrds.org/2020/). This tool is helpful in understanding which aspects are improving and those where action still needs to be taken in order to improve CKD prevention and treatment. Anyone can easily log on to the above link, view the records, and even download the spreadsheets made available in Microsoft Excel format.

The factors responsible for this rising epidemiologic trend are mainly global population growth and an aging population [8]. Both of these factors have resulted in a concomitant increase in the number of patients with comorbidities that tend to be more common with increasing age and increase the risk of developing CKD, such as hypertension, diabetes mellitus, and cardiovascular disease. This negative trend has not been followed by adequate implementation of health policies aimed at preventing and adequately controlling CKD. The main driving factor behind this phenomenon is the fact that CKD is asymptomatic until the advanced stages of the disease Both the reduction of eGFR and the presence of albuminuria are in the early stages silent, and are recognized only when the patient undergoes either voluntarily or by indication of the general practitioner (mmg), to a blood draw for creatininemia assay (from which eGFR can be calculated) and a urine test, either morning or with 24-hour collection, for albuminuria assay. A 'survey conducted among mmg and involving more than 450,000 patients showed that only slightly more than 17% of the total number of patients had had a blood draw for creatininemia assay and, among those in the early stages of CKD, only 5% were referred to nephrology specialist care [9]. Added to this phenomenon is the low awareness that CKD patients, on average, have regarding the severity of this clinical condition, the so-called "awareness" [10]. All these factors, particularly the high prevalence of CKD and the asymptomaticity of its early stages, have led to the appropriate definition of CKD as a silent epidemic (http://www.healthdesk.it/scenari/malattia-renale-cronica-epidemia-silenziosa). The repercussions of such a "silent epidemic" are of enormous clinical-socioeconomic dimensions and are an urgent global public health problem, not just an individual one. Suffice it to say that the costs required to be able to treat CKD collectively cover as much as 4.5 percent of national health spending in Italy, hovering around 5 billion euros/year (http://www.quotidianosanita.it/lettere-al-direttore/articolo.php?articolo_id=3253).

There is therefore a perception today that one of the starting points for significantly improving this situation, in an attempt to reverse the trend of CKD prevalence, is to provide the population with more up-to-date and detailed 'information about the issue, as it is not being considered, as it deserves to be on the basis of what has been presented so far, adequately enough by the mass media and the general public. The strategy of "starting by informing" is more relevant than ever. An example of this is the initiative of Niguarda Hospital in Milan, which, for the Lombardy Region, has created a specific web page where useful information on CKD is provided (https://www.ospedaleniguarda.it/news/leggi/reni-patologie-silenziose-in-aumento). In addition, although there is still no real CKD screening program, it is now widely accepted suggestion towards every adult individual, to practice periodic urine testing, which is inexpensive and easy to perform, and blood pressure monitoring (http://www.ladialisiperitoneale.it/gli-screening-per-la-diagnosi-precoce-delle-nefropatie/), as necessary tools for early diagnosis of CKD in order to be able to avoid  the occurrence of its complications.

Bibliographical References

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