Chronic Kidney Disease: The Silent Epidemy

Numerous observations suggest that chronic kidney disease (CKD) is an epidemic condition [...].

Numerous observations suggest that chronic kidney disease (CKD) is an epidemic condition [1]. Although its prevalence varies according to geographical region, it has been reported that about 8-10% of the population show some degree of renal function impairment [1]. It is worth noting that CKD not only portends poor prognosis but it has also been demonstrated that CKD patients are among the most complex subjects (complexity being defined as number of comorbidities, presence of mental illness, number of types of physicians involved in each patient's care, number of physicians involved in each patient's care, number of prescribed medications, number of emergency department visits, rate of death, rate of hospitalization, and rate of placement in a long-term care facility) to be managed, and consumes a large proportion of health care resources [2].
Contrary to diabetes or other metabolic diseases as prevalent as CKD, renal function impairment is often asymptomatic or pauci-symptomatic until very late stages of the disease. However, in the course of the disease many metabolic abnormalities may develop and aggravate patients' well-being and prognosis [3]. Needless to say, great effort is being devoted to characterizing clinical symptoms, developing diagnostics, as well as treatments, to prevent CKD occurrence or progression toward end stage renal disease (ESRD).
The aim of this special issue is to collect data and share ideas on different aspects of these topics. The 25 papers published (Table 1) and the 26 (highest citations of 9) citations document will be of interest to investigators and readers interested in the complexity of CKD. Four articles [4][5][6][7] investigated the usefulness of various biomarkers to assess renal function or complications associated with CKD in adult, as well as pediatric, patients. Indeed, current strategies to assess renal function rely on serum creatinine levels a marker highly influenced by factors such as age, gender, race, comorbid conditions and/or use of concomitant medications. These articles highlight the need for a more accurate approach to assess the presence and severity of renal impairment [8]. Similarly, nephrologists' lack of an accurate prognostic score system that integrates serological and histopathological pieces of information is documented in two other studies [9,10] published within this special issue.
Four other articles [11][12][13][14] report on the complicated interplay between CKD and other comorbid conditions. Although prevalence varies according to the region of the world, diabetes and Human Immunodeficiency Virus (HIV) infection are among the most common factors associated with renal dysfunction [12][13][14]. All comorbid conditions need to be taken into account to individualize and improve patient care. However, these articles call for more and dedicated studies to address how to appropriately manage highly comorbid CKD patients, especially in consideration of the fact that these subjects are often excluded by randomized clinical trials (RCT).
Other articles investigate the prevalence and impact of common metabolic abnormalities that frequently complicate the course of CKD in children or adults [15][16][17]. CKD should be perceived as a multifaced metabolic disease that accelerates aging. Anemia, hypoglycemia and phosphate metabolism abnormalities are only some examples of factors that have been associated with Cardio-Vascular (CV) senescence and/or morbity and mortality [15][16][17]. Indeed, as renal function declines, several toxins may accumulate and exert detrimental effects on various metabolic pathways including promoting inflammation and renal damage progression [18][19][20]. In these perspectives, balanced nutrition may modulate the intestinal microbiota [21,22], reduce some toxin productio, and accumulation, and hold promise to impact renal and overall survival of CKD patients [21,22].
Several other therapies have been proposed to tackle the abysmal risk of renal, cardiovascular and all-cause events at which CKD patients are exposed. Overall, eight out of 25 articles (32%) address the impact of different treatment strategies on various outcomes [23][24][25][26][27][28][29]. However, none of these reports on results of an RCT. Although this may be expected for a special issue of a journal of internal medicine, it also reflects the paucity of RCTs in the nephrology arena and the desperate call for more and ad hoc studies to investigate the impact and potential interaction of available drugs on renal function and outcomes of CKD patients.
In conclusion, the articles published in this issue reflect the complexity of CKD and the limitations of available tools to detect renal dysfunction and metabolic abnormalities associated with CKD, as well as the paucity of data to properly treat these patients. Nevertheless, they expand current understanding in some areas of nephrology and generate hypothesis to be tested in future studies.