BACKGROUND/AIMS

Few studies have compared population-based tuberculosis (TB) incidence rates by end-stage renal disease (ESRD) status. No studies have compared TB genotypes by ESRD status to determine whether TB disease resulted from recent transmission or reactivation of latent TB infection (LTBI). We calculated TB incidence rates and compared demographic and clinical characteristics and genotypes among TB cases by ESRD status.

METHODS

This analysis was based on prospective surveillance for TB cases during 2010 in California. Clustered genotype was defined as ≥2 culture-positive TB cases with matching genotypes in the same county. The χ(2) or Wilcoxon rank-sum test was used to compare variables.

RESULTS

During 2010, 83 TB cases with ESRD and 2,244 cases without ESRD were reported in California; TB incidence rates were 110.3/100,000 and 6.0/100,000, respectively. ESRD case patients versus patients without ESRD were more likely to be older (median age 66 vs. 49 years; p < 0.001), foreign-born persons who had arrived in the USA >5 years before TB diagnosis (97 vs. 75%; p < 0.001) and dead at TB diagnosis (7 vs. 2%; p = 0.01). ESRD patients were less likely to have a positive tuberculin skin test (50 vs. 80%; p < 0.001), positive acid-fast bacilli sputum smears (33 vs. 53%; p = 0.01) and cavities on chest radiography (6 vs. 21%; p = 0.01). No differences in proportions of clustered TB genotypes were detected (20 vs. 23%; p = 0.54).

CONCLUSIONS

Rates of TB are 18 times higher in California's ESRD population, and TB disease likely occurred due to LTBI reactivation because few patients had clustered genotypes. Efforts to prevent TB among ESRD patients may require the use of newer diagnostic tests and promotion of LTBI treatment.

African Americans face higher risk of AKI than Caucasians. The extent to which this increased risk is because of differences in clinical, socioeconomic, or genetic risk factors is unknown. We evaluated 10,588 African-American and Caucasian participants in the Atherosclerosis Risk in Communities study, a community-based prospective cohort of middle-aged individuals. Participants were followed from baseline study visit (1996-1999) to first hospitalization for AKI (defined by billing code), ESRD, death, or December 31, 2010. African-American participants were slightly younger (61.7 versus 63.1 years, P<0.001), were more often women (64.5% versus 53.2%, P<0.001), and had higher baseline eGFR compared with Caucasians. Annual family income, education level, and prevalence of health insurance were lower among African Americans than Caucasians. The unadjusted incidence of hospitalized AKI was 7.4 cases per 1000 person-years among African Americans and 5.8 cases per 1000 person-years among Caucasians (P=0.002). The elevated risk of AKI among African Americans persisted after adjustment for demographics, cardiovascular risk factors, kidney markers, and time-varying number of hospitalizations (adjusted hazard ratio, 1.20; 95% confidence interval [95% CI], 1.01 to 1.43; P=0.04); however, accounting for differences in income and/or insurance by race attenuated the association (P>0.05). High-risk APOL1 variants did not associate with AKI among African Americans (demographic-adjusted hazard ratio, 1.07; 95% CI, 0.69 to 1.65; P=0.77). In summary, the higher risk of AKI among African Americans may be related to disparities in socioeconomic status.