Long-term outcomes of asymptomatic microscopic haematuria in an outpatient department

Background: Asymptomatic microscopic haematuria (AMH) is frequently detected in outpatient settings. However, its long-term outcomes and association with serious urological conditions; such as genitourinary cancer, urolithiasis, and glomerular disease, remain underexplored. Understanding these associations is essential for improving the diagnostic and management strategies within public health settings. Methods: This study aimed to determine the underlying causes of AMH in an outpatient department after long-term follow-up. It is a descriptive longitudinal study on outpatients with AMH. Medical records from January 1, 2012., were reviewed: in total of 410 patients were included and followed up until 31 December 2022; or until a definitive diagnosis was established. Results:Among the 410 patients (mean age, 57 years), geometric mean of follow-up time, 2 years 9 months, was used due to skewed follow-up times (95%CI=2.4 to 3.2). The long-term outcome of serious disease (Genitourinary malignancy, urolithiasis, Glomerular disease) in patients with AMHwas 19.0%. Specifically, 61 patients (14.9%) were diagnosed with urolithiasis, 3 (0.7%) with genitourinary malignancy, and 14 (3.4%) with glomerular disease. Male and a high blood cell count on urinalysis were significantly associated with major disease (p < 0.01 and p < 0.05, respectively) Conclusion: Serious disease was identified in 19.0% of patients with AMH.  Although a small number of red blood cells in the urine may initially appear clinically insignificant, it could be associated with underlying serious pathology, particularly among male patients. Keywords:  Hematuria, Outpatient, Urological disease, Longitudinal study, Thailand