Chronic kidney disease (CKD) is considered a major health problem, which poses a burden for health care systems worldwide. It has been estimated that 10% of the population worldwide have CKD; however, most of the cases are undiagnosed. If left untreated, CKD could lead to kidney failure, which highlights the importance of early diagnosis and treatment. Pyuria has been reported in CKD patients, and could be the result of several comorbidities, such as diabetes, or urinary tract infections (UTIs). A few studies have shown that pyuria is associated with the late stages of CKD. However, there are limited data on the prevalence of non-UTI (sterile) and UTI-pyuria in different CKD patient populations, and its association with the decline in kidney function and progression of CKD. In this retrospective study, we report the prevalence of pyuria (sterile and UTI) in 754 CKD patients of King Fahd Specialist Hospital, Buraydah, Saudi Arabia. Our data showed that 164/754 CKD patients (21.8%) had pyuria, whereas 590 patients (78.2%) presented with no pyuria. There was a significantly higher percentage of late-stage (stage 4) CKD patients in the pyuric group compared to the non-pyuric group (36.6% vs. 11.9%). In line with the previous data, proteinuria was detected in a significantly higher percentage of pyuric patients, in addition to significantly higher levels of serum creatinine and urea, compared to non-pyuric patients. Furthermore, 13.4% of the pyuric CKD patients had UTI, whereas 86.6% presented with sterile pyuria. E. coli was indicated as the causative agent in 45.5% of UTI patients. Our patient data analysis showed that a significantly higher percentage of UTI-pyuric CKD patients, than sterile pyuric patients (63.6% vs. 19.7%), had higher numbers of urinary white blood cells (>50/HPF, WBCs). The data also showed that a higher percentage of UTI-pyuric patients were late-stage CKD patients, compared to sterile pyuric patients (50% vs. 34.5%). Our findings indicate that a high level of pyuria could be considered as a marker for late-stage CKD, and that UTI is an important risk factor for the decline in kidney function and the progression to late-stage CKD. We believe that further studies are needed to correlate pyuria to kidney function, which could be helpful in monitoring the progression of CKD. Moreover, the management of comorbidities, such as diabetes and UTIs, which are risk factors for CKD and associated pyuria, could help to control the progression of CKD to the late stages.
Keywords: CKD; E. coli; UTI; WBCs; albuminuria; bacteria; leukocyte esterase; pyuria; urinary nitrite; urine.