Chronic Kidney Disease of Unknown Etiology: A Single-center Cross-sectional Study.

Globally, chronic kidney disease of unknown etiology (CKDu) has been recognized as an emerging cause contributing to the rise in chronic kidney disease (CKD). Nevertheless, in the Kingdom of Saudi Arabia, the epidemiology of CKDu remains understudied. The aim of this study was to assess the epidemiological, clinical, and laboratory characteristics of the CKDu population. From May 2021 to May 2022, a retrospective cross-sectional study was conducted on patients with Stage 4-5 CKD who presented to King Fahd Hospital in Jeddah. On the basis of the cause of CKD, patients were categorized into two groups: those with traditional risk factors for CKD (CKDt) and those without a recognizable cause of CKD (CKDu). Out of a total of 500 patients with Stage 4-5 CKD who were enrolled in the study, 100 patients were found to have CKDu. Compared with the 400 patients with CKDt, the patients in the CKDu group were younger (a mean age of 52.3 years vs. 66.1 years, P <0.001), with the majority in the middle age group of 40-65 years old (68% vs. 43%, P <0.001). They were predominantly males (72% vs. 56%, P = 0.003), with less hyperkalemia (4.29 vs. 5.13, P <0.043), and presented without a previous history of CKD (57% vs. 31%, P = 0.001). Among the 500 patients who were studied, 100 patients (20%) presented with CKDu who were predominantly younger males without a known history of CKD. Further studies on a nationwide scale are warranted.