Risk of tuberculosis in dialysis patients: association of tuberculin and 2,4-dinitrochlorobenzene reactivity with risk of tuberculosis.
BACKGROUND
Dialysis patients are at increased risk of tuberculosis (TB) and anergy due to attenuated cellular immunity.


OBJECTIVE
To define specific risks of TB in anergic and non-anergic dialysis patients.


METHODS
A total of 272 dialysis patients were enrolled in this prospective study over a 36-month follow-up. Entering the study, participants had Mantoux and 2,4-dinitrochlorobenzene skin tests and their cell-mediated immunity (CMI)-index was estimated. Patients were classified as anergic (CMI-index<or=2 and Mantoux<or=4 mm) or non-anergic. Specific relative risks of TB were then calculated, using data from both the general population and 49 non-uremic health care workers. The independent effect of sex, age and diabetes mellitus was determined using Cox's proportional hazard method.


RESULTS
Among the 116 (42.6%) anergics 13 (11.2%), and among the 156 non-anergics 11 (7%) developed active tuberculosis. Anergics had a significantly higher risk of TB than non-anergics (Adjusted Relative Risks, 98.3, 95% CI 58.65-113.6 versus 61.6, 95% CI 13.6-72.1, P=0.003). Tuberculin reactivity was weakly associated with the subsequent risk of TB (r=0.51). The latter showed a steadily decreasing trend with increasing CMI-index (r=-0.99).


CONCLUSIONS
Anergy distorts the association of tuberculin reactivity with risk of TB. Anergic dialysis patients are at increased risk of developing active TB and chemoprophylaxis is justified in them too.
Christopoulos
A I
AI
Department of Nephrology of St. Andrew General State Hospital, and Department of Radiology, University Hospital Rio, Patra, Greece. antochrist2004@yahoo.com
Diamantopoulos
A A
AA
Dimopoulos
P A
PA
Gumenos
D S
DS
Barbalias
G A
GA
D000328:Adult; D000368:Aged; D004137:Dinitrochlorobenzene / Q000276:immunology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D006435:Renal Dialysis; D012307:Risk Factors; D012882:Skin Tests; D014373:Tuberculin / Q000276:immunology*; D014376:Tuberculosis / Q000175:diagnosis* / Q000276:immunology*
D004137:Dinitrochlorobenzene; D014373:Tuberculin