Patients with haematuria may be at increased risk of chronic kidney disease (CKD)—that’s the conclusion of a new study in the American Journal of Kidney Diseases (AJKD). Led by Seungho Ryu and Yoosoo Chang (Sungkyunkwan University School of Medicine, Seoul, South Korea), the study authors performed a retrospective cohort analysis to investigate the risk of developing CKD associated with microscopic blood in a patient’s urine.
Beginning by noting previous research in the area, the authors drew attention to the work of Asaf Vivante (Sheba Medical Centre, Tel Hashomer, Israel) et al in 2011, which argued that haematuria was “associated with significantly increased risk of treated end-stage renal disease (ESRD)” over a 22-year period. However, they said, there were no studies that had examined change in haematuria over time and its connection to CKD. They look to rectify that.
The retrospective cohort study examined the data of 232,220 patients from the Kankbuk Samsung Health Study. The patients received “comprehensive health examinations” at least twice between 2011 and 2018, with a follow-up before the end of 2020. This examination included blood pressure, estimated glomerular filtration rate (eGFR), serum creatinine and other measurements. Urinalysis of protein and blood cells was performed of “fresh and midstream spot urine samples” of all patients, and haematuria changes were determined at baseline and follow-up.
The primary endpoint of the study was incident CKD, while secondary endpoints included decreased eGFR and proteinuria. Hazard ratios were calculated based on this data as well and were adjusted for “age and sex, and then further adjusted for centre”. Other factors in a patient’s background were then also controlled for, including the influence of menstrual cycle and menopause for female patients.
The results showed statistically significant association between haematuria and development of CKD. Male patients who experienced persistent haematuria had a 8.3-fold increased risk of developing CKD, while those who developed it had a 4.4-fold increased risk and those whose haematuria regressed had a 2.8-fold increased risk. Women with persistent haematuria had a 3.9-fold increased risk and those who developed it had a 2.5-fold increased risk. Each of these was statistically significant, and the authors said it reflected that microscopic haematuria was “significantly associated with subsequent CKD incidence… in both sexes,” despite a stronger association for men.
One point the team noted was those microscopic haematuria in premenopausal women was “commonly considered a benign finding,” something brought into question by the results of their study. They described the reason for the differences in strength of association between the sexes as “unclear,” requiring exploration in further studies. Finally, they noted limitations including the lack of renal biopsies among the patient cohort, which limited their data, as well as the overall low number of incident CKD in their study, something which they suggested should prompt further study. Nevertheless, they said such further study could build on the strengths of their own to determine “whether appropriate management of haematuria can help decrease subsequent CKD risk and progression to renal failure”.