TUBERCULOSIS INFECTION AND ANERGY IN HEMODIALYSIS-PATIENTS

Patients on hemodialysis are at increased risk for developing active t uberculosis (TB) after primary infection. Although this increased risk is well documented, the prevalence of TB infection, as indicated by a positive tuberculin skin test (TST), is not well described. End-stage renal disease is also known to be a risk factor for skin test anergy, but the rate of anergy in hemodialysis patients is unclear. We sought to identify rates of anergy and TST positivity in patients at four he modialysis units in St Louis, Missouri, from June 1996 through August 1996. Data obtained from patients and medical records included age, ye ars on hemodialysis, medical history, and basic laboratory data. Patie nts without a history of TB or a positive TST had a TST with Tubersol, as well as candida and tetanus controls, placed by the Mantoux method . Tests were read 48 hours later. Of the patients enrolled at these un its, 307 of 331 (93%) were evaluated. Patients had a mean age of 58 ye ars (range, 19 to 91 years) and had been on hemodialysis for a mean of 3.7 years (range, 1 week to 18.7 years). Blacks made up 81% of the po pulation. A history of a positive TST was obtained from 24 patients (8 %), and an additional seven (2%) had a history of active TB. Of the 27 6 patients tested, 93 did not respond to either control antigen, but f ive of these patients had a positive TST, leaving 88 (32%) anergic. An ergy was related to age, immunosuppressive drug use, and the reagents used, but not to urea reduction ratio. Positive TSTs were found in 17 of 188 of nonanergic patients (9%) (6% of all tested patients). Overal l, 48 of 307 patients (16%) had a positive TST or history of TB. TB or a positive TST was associated with liver disease and peptic ulcer dis ease, but not socioeconomic status. All 17 newly identified TST-positi ve patients received chest radiographs. No new cases of active TB were found. Only two of 17 of these patients (12%) were started on isoniaz id (INH) prophylaxis. We identified high rates of TST positivity and a nergy in the hemodialysis patients tested. Hemodialysis patients shoul d receive regular TST screening, and INH prophylaxis needs to be more strongly encouraged. Studies are ongoing to define the rate of TST con version over time. (C) 1998 by the National Kidney Foundation, Inc.