Tuberculosis among Egyptian Patients on Hemodialysis

Hemodialysis (HD) patients are at increased risk of latent tuberculosis (LTB) infection. It is commonly thought to be associated with a very poor prognosis and it is difficult to diagnose. LTB screening of this population is recommended. The Mycobacteria Growth Indicator Tube (MGIT) may be more accurate than the tuberculin skin test (TST) in the detection of LTB.

We prospectively compared the results of MGIT and Lowenstein– Jensen (LJ) medium to TST for the recovery of TB from 91 HD patients. The Patients were on a HD program for more than 1 year. Data obtained from patients and medical records included medical history (past history of TB, Bacillus Calmette^Guerin [BCG] vaccination, history of contact with previous TB cases), radiography reports (chest x-ray for TB changes), and basic laboratory investigations. Using Cox's proportional hazard model and Odds hazard ratio, the independent effects of various risk factors associated with TB development were estimated.

Five of 91 patients (5.5%) had a positive MGIT and LJ tests results and 26 (28.6%) had a positive TST test result. Overall agreement between the MGIT and TST was in one patient. Discordant test results were seen in 25 TST-positive/MGIT negative patients and in 4 TST-negative/MGIT-positive patients. On Odds ratio analysis, the risk factors for MTB infection in HD patients are older age (> 50 years) and duration dialysis (> 2years). MGIT Drug susceptibility testing showed that all isolated strains were resistant to all first line anti-tuberculus drugs except 1 strain showed only sensitivity to Rifampicin.

MTB infection is 5.5% of Egyptian ESRD patients. MGIT test results were more useful diagnostic method than TST for detecting LTB in HD patients.