Prognostic factors for long-term outcomes of unilateral atrophic kidneys in adult patients: a single-center retrospective cohort study.

Background/aim: Unilateral atrophic kidney (UAK) could be related to many etiologies that can cause chronic kidney disease in adults. There is limited data on the long-term outcome of adults with UAK in the literature. Materials and methods: This study included 199 adult patients with UAK. The etiology, baseline clinical/laboratory, and radiological findings were evaluated. Composite primary outcomes (CPO) (chronic kidney disease stage 5 or doubling of serum creatinine) and secondary outcomes (new-onset proteinuria (>0.5 g/day or g/g) or >50% increase in proteinuria level according to baseline, mortality, and nephrectomy requirement during follow-up) were evaluated in 166 patients with at least 3 months of follow-up. Results: Of 199 patients, 57.3% were female. The mean age at presentation was 44.4 years. Right and left kidney atrophy rates were 51.8% and 48.2%, respectively. Among the known etiologies, the most common was chronic pyelonephritis (17.1%, n = 34). Of 166 patients, 19 had a CPO. Patients with CPO had higher rates of hypertension (p = 0.033), proteinuria (p < 0.001), and renal artery stenosis. Baseline systolic blood pressure (p = 0.004) and serum creatinine (p < 0.001) were higher, and baseline eGFR (p < 0.001) and serum albumin (p = 0.001) were lower in these patients than in patients without CPO. Multivariate logistic regression analysis showed that baseline creatinine (p < 0.001), serum albumin (p = 0.034), and renal artery stenosis (p = 0.015) were independent risk factors for CPO. Conclusion: Higher baseline serum creatinine and lower serum albumin levels were associated with poor renal prognosis in adult patients with UAK. Also, UAK due to renal artery stenosis might be associated with worse outcomes than UAK related to other etiologies.