Chronic kidney disease with genitourinary tuberculosis: old disease but ongoing complication

Research article Open Access Open Peer Review Chronic kidney disease with genitourinary tuberculosis: old disease but ongoing complication Eun Jin Kim1, Woonji Lee2, Woo Yong Jeong2, 3, Hen Choi2, 3, In Young Jung2, 3, Jin Young Ahn2, 3, Su Jin Jeong2, 3, Nam Su Ku†2, 3Email authorView ORCID ID profile, Jun Yong Choi2, 3, Young Hwa Choi†1Email author, Young Goo Song2, 3 and June Myung Kim2, 3 †Contributed equally BMC Nephrology201819:193 https://doi.org/10.1186/s12882-018-0994-2 ©  The Author(s). 2018 Received: 22 January 2018Accepted: 26 July 2018Published: 2 August 2018 Open Peer Review reports Abstract Background Genitourinary tuberculosis (GUTB) is a type of extrapulmonary TB that exerts a deleterious effect on renal function by promoting renal calcification and ureteric stricture. Therefore, we investigated the risk factors for chronic kidney disease (CKD) in GUTB patients after the end of treatment. Methods This retrospective study was conducted at a tertiary hospital in South Korea. Data from patients (>18 years of age) with GUTB were collected from January 2005 to July 2016. CKD was defined as a glomerular filtration rate <60 mL/min/1.73m2 after the end of treatment. Results In total, 56 patients with GUTB (46.4% males; mean age 52.8 ± 16.6 years) were enrolled in the study. CKD developed in 11 (19.6%) patients and end-stage renal disease in 4 (7.1%). In a univariate analysis, older age (p = 0.029), microscopic haematuria (p = 0.019), proteinuria (p = 0.029), acute renal failure (ARF) (p < 0.001) and a positive polymerase chain reaction-based test result for TB in the urine (p = 0.030) were significantly associated with decreased renal function. In a multivariate analysis, ARF (odds ratio [OR], 54.31; 95% confidence interval [CI], 1.52–1944.00; p = 0.032) and old age (OR, 54.26; 95% CI, 1.52–1932.94; p = 0.028) were independent risk factors for CKD in GUTB patients. Conclusions ARF and old age were independent risk factors for CKD in GUTB patients. Therefore, in elderly GUTB patients with ARF at the time of diagnosis, regular follow-up of renal function should be performed even after the end of treatment. Keywords Genitourinary tuberculosisChronic kidney diseaseRisk factor Background Tuberculosis (TB) is an important unresolved public health issue, affecting millions of people each year. In 2015, TB was one of the top 10 infectious causes of death worldwide; there were 10.4 million new TB cases, equivalent to 142 cases per 100,000 population, and 1.4 million deaths due to TB, with an additional 0.4 million deaths resulting from TB among human immunodeficiency virus (HIV)-positive persons [1]. South Korea has an intermediate burden of TB; according to the Korea Center for Disease Control, the estimated TB incidence is 63.2 cases per 100,000 population (in 2015, n = 32,181). Extrapulmonary TB (EPTB) accounted for 13.0% of all new cases reported in 2015 (n = 6631). Genitourinary TB (GUTB) is a type of EPTB that infected 199 individuals in South Korea in 2015, accounting for 3.0% of all EPTB cases [2, 3]. Although GUTB is a rare form of EPTB, it is an important cause of progressive chronic kidney disease (CKD). The kidneys are the most common site of GUTB, with bacteria spreading haematogenously. Tuberculous bacilli can lead to granuloma formation in glomeruli and entry into the medullary interstitium. Subsequently, renal papilla destruction can develop due to calyceal ulceration and involvement of the collecting system. This destruction may extend towards the urothelium and induce stricture formation, resulting in hydroureter and hydronephrosis. Renal calcification in GUTB is common, and patients with renal TB can develop bladder contracture. In addition, TB can affect the male and female genital tracts [4, 5]. GUTB induces end-stage renal disease (ESRD) in 5.7% of patients [5]. According to the European Dialysis and Transplant Association registry, 0.65% of new dialysis cases are caused by renal TB [6]. In Korea, there were 14,756 new dialysis patients in 2015, of whom 0.1% required dialysis because of GUTB [7, 8]. However, in a previous autopsy study, only 50% of patients with GUTB were symptomatic, and only 18% had received a clinical diagnosis [5]. Additionally, the clinical manifestations of GUTB are nonspecific [9]. Thus, the diagnosis is often delayed, during which GUTB progression may lead to CKD due to parenchymal destruction and obstructive uropathy. Therefore, we investigated the characteristics of urogenital TB in adult patients with no history of CKD in a single-centre retrospective observational study and identified risk factors for CKD development after ending GUTB treatment. Methods Study population and design We conducted this retrospective study at the Severance Hospital, a 2400-bed university-affiliated teaching hospital and tertiary care referral hospital in Seoul, South Korea. We enrolled participants older than 18 years of age diagnosed with GUTB. We identified patients with ICD-10 codes A18.1, B90.1 and N33.0 from January 2005 to July 2016 from electronic medical records and enrolled only those who started and completed the treatment during the study period. Clinical and laboratory data at the time of GUTB diagnosis, including age, sex, medical history, follow-up duration and symptoms, were collected. To assess renal function, serum creatinine levels were reported before treatment and at the 6- and 12-month post-treatment follow-ups. Body mass index (BMI) was calculated as weight divided by height squared (kg/m2). We also investigated the diagnostic methods, treatment modalities and outcomes of GUTB patients during a recent 10-year period in one centre in Korea to identify risk factors for CKD developing after ending treatment. All surgical techniques were investigated included all ablative surgery and reconstructive surgery between diagnosis and during medical treatment. We excluded patients with a follow-up duration of <1 year, unfulfilled GUTB diagnostic criteria, pre-existing CKD and insufficient data. This study was approved by the Institutional Review Board of the Yonsei University Health System Clinical Trial Center. Definitions The diagnosis of GUTB was defined as the presence of any clinical finding plus a positive result for one of the following: (1) acid-fast bacilli (AFB) in urine, (2) urine culture of Mycobacterium tuberculosis (M. tuberculosis), (3) polymerase chain reaction (PCR) for M. tuberculosis in urine or (4) histopathological evidence of TB in any GU tissue specimen. A histological diagnosis of TB was confirmed by identifying caseating necrosis, loose aggregates of epithelioid histiocytes and Langerhans giant cells in tissue specimens [6, 10]. Immunosuppressant use was defined as a daily dose of ≥20 mg prednisolone-equivalent steroid, monoclonal antibodies, antimetabolite drugs or T-cell inhibitors within 30 days prior to diagnosis of GUTB. Pre-TB (pre-exis (...truncated)