Risk factors for Mycobacterium tuberculosis in US chronic dialysis patients

Background. End-stage renal disease is known to disrupt the cell-mediated immune response that is responsible for the killing of intracellular organisms such as Mycobacterium tuberculosis. Risk factors that contribute to the development of tuberculosis (TB) disease in the US dialysis population have not been studied on a large scale. Methods. A retrospective cohort study of TB disease in 272 024 patients in the US Renal Data System initiated on dialysis therapy between 1 April 1995 and 31 December 1999 with Medicare or Medicaid as primary payer were analysed. A total of 21 risk factors were analysed. Results. Among the US population studied, there is a 1.2 and 1.6% cumulative incidence of TB in patients undergoing either peritoneal or haemodialysis, respectively. Ten risk factors for TB that proved to be statistically significant included advanced age (P < 0.001), unemployment (P < 0.001), Medicaid insurance (P < 0.001), reduced body mass index (P < 0.001), decreased serum albumin (P < 0.001), haemodialysis (P = 0.019), both Asian (P = 0.010) and Native American (P = 0.020) race, ischaemic heart disease (P = 0.032), smoking (P = 0.010), illicit drug use (P = 0.018) and anaemia (P = 0.028). TB was independently associated with increased mortality, adjusted hazard ratio (AHR) 1.42 (95% CI 1.18-1.70, P < 0.001). Conclusions. The prevalence of TB disease in the US dialysis population is low compared with worldwide rates; however, the disease is associated with increased mortality. Of the 10 significant risk factors identified, five are potentially modifiable.