#1250 Latent tuberculosis in advanced chronic kidney disease- single centre experience in the UK

Abstract Background and Aims As of 2022, England remained a low tuberculosis (TB) incidence country with a TB notification rate of 7.75 per 100,000 population, below the World Health Organization (WHO) threshold (10 per 100,000 population). Over a lifetime, a healthy individual with latent TB has a 10–15% chance of developing active TB infection. Patients receiving hemodialysis are at increased risk of latent TB reactivation with estimations as great as 25 times that of an otherwise healthy individual. The WHO recommends testing for all patients receiving dialysis. In a published report from Birmingham in 2018, the overall incidence of active TB within the 8767 strong renal cohort over a decade, was 126/100,000 patient-years ranging from 92/100,000 in those with CKD 1 or 2 to 257/100,000 patient-years in those receiving dialysis (Journal of Infection, 77, 2018). Most TB cases reported in the NW England in 2021, were born outside the UK (72.9%). Of these, 16.4% were diagnosed within one year of entry and 39.5% were diagnosed 11 or more years after entry (gov.uk/regional reports). Informed by the increased incidence of patients presenting with advanced chronic kidney disease, born outside the UK, we launched a new testing program for latent and active tuberculosis in patients attending the renal center in Manchester, UK. Method This is a single centre report of incidence of TB specifically in patients with Advanced CKD- eGFR < 30 mls/min, including those on dialysis. Electronic records were used for data capture over a three-year period. 4672 patients had advanced CKD and therefore deemed to be the ‘at-risk’ group. Gamma Interferon Assay was employed as the test for latent TB detection. Of the at-risk group, 707 patients were tested prior to commencement of immunosuppression (either transplant or autoimmunity related). Clinical and treatment variables were also obtained. Descriptive analysis has been carried out. Results Over the three-year period, 76 patients were found to have either confirmed or indeterminate reports on Gamma Interferon assay. Median age of patients was 60.5 years and 68% were male. 27.6% of patients belonged in the White British category. Patients of Pakistani origin dominated the proportion of patients in the ethnic minority group (23%). 26% of patients also had diabetes and 35.5% were on dialysis therapy. 26.3% of patients were actively immunosuppressed and 38.2% were on steroid therapy. 35% of these cases were detected when screening was undertaken as part of transplantation work-up. Inadequate information was available on historic BCG vaccination. 13.2% of patients also had past treatment for tuberculosis. 24% of GIFN positive patients had histological/microbiological evidence of tuberculosis and 7.8% had extrapulmonary TB. 44.7% of patients went on to receive treatment with anti-tuberculosis therapy. The reasons for others not receiving treatment include non-referral/ refused therapy or did not attend clinics. Mean duration of treatment was 3.7 months. A third of the patients on treatment experienced treatment-related side effects. Within the scope of the somewhat limited uptake of GIFN testing amongst practitioners during this period, the incidence rate of active tuberculosis in this cohort is 92.7/100,000 patient-years. The incidence rate of GIFN positive patients in this at-risk group is 392.4/100,000 patient-years. Conclusion The incidence of latent tuberculosis in advanced CKD population is significantly high in our unit. Active case finding in this at-risk group is essential, as part of routine preventative care.