Association of vitamin D levels and risk of latent tuberculosis in the hemodialysis population

Revisiting the association between vitamin D deficiency and active tuberculosis: A prospective case-control study in Taiwan

BACKGROUND

To revisit the association between vitamin D deficiency (VDD, defined as serum 25(OH)D < 20 ng/ml) and incident active tuberculosis (TB), after two potentially underpowered randomized trials showed statistically non-significant 13%-22% decrease in TB incidence in vitamin D supplementation groups.

METHODS

We prospectively conducted an age/sex-matched case-control study that accounting for body-mass index (BMI), smoking, and other confounding factors to examine the association between VDD and active TB among non-HIV people in Taiwan (latitude 24°N), a high-income society which continues to have moderate TB burden.

RESULTS

We enrolled 62 people with incident active TB and 248 people in control group. The TB case patients had a significantly higher proportion of VDD compared to the control group (51.6% vs 29.8%, p = 0.001). The 25(OH)D level was also significantly lower in TB patients compared to control group (21.25 ± 8.93 ng/ml vs 24.45 ± 8.36 ng/ml, p = 0.008). In multivariable analysis, VDD (adjusted odds ratio [aOR]: 3.03, p = 0.002), lower BMI (aOR: 0.81, p < 0.001), liver cirrhosis (aOR: 8.99, p = 0.042), and smoking (aOR: 4.52, p = 0.001) were independent risk factors for incident active TB.

CONCLUSIONS

VDD is an independent risk factor for incident active TB. Future randomized trials examining the effect of vitamin D supplementation on TB incidence should focus on people with a low BMI or other risk factors to maximize the statistical power.

Assessment of the Association of Vitamin D and the Risk of Tuberculosis among End-Stage Kidney Disease Population

We investigated the role of vitamin D in the risk of tuberculosis (TB) among patients with end-stage kidney disease (ESKD). The retrospective cohort was conducted with data of 20,985 patients with kidney disease and 20,985 controls without kidney disease (1:1 matching on age of cohort entry and sex) in the duration of 1997−2010 from the Taiwan National Health insurance database. Then, by a case−cohort study, among 20,985 kidney disease, 3194 ESKD patients were identified with matched 3194 non-ESKD patients. Multivariate analyses revealed a significant association between kidney disease and tuberculosis (adjusted incidence rate ratio (IRR) 1.57 (1.33−1.86)), and the risk increased after 3 years of follow-up the (adjusted IRR 3.79 (2.55−5.62)), but after more years of follow-up no significance was observed. We also found that ESKD increases the risk of tuberculosis (adjusted IRR 3.67 (2.27−5.93)). However, vitamin D usage was not related with the tuberculosis risk in ESKD patients (p > 0.1783). Our study showed increased risk of tuberculosis in kidney disease and ESKD patients, and vitamin D was not beneficial in ESKD.

Tuberculosis treatment delay and nosocomial exposure remain important risks for patients undergoing regular hemodialysis

BACKGROUND AND OBJECTIVE

Studies have reported an increased tuberculosis (TB) incidence among patients with end-stage renal disease (ESRD). This nationwide nested Case-control study investigated the risk of active TB due to nosocomial exposure and its correlation with the delay in TB treatment in hemodialysis patients.

METHODS

Adult (aged ≥20 years) patients with incident ESRD over 2000-2010 were identified from Taiwan National Health Insurance Research Database; 2331 patients with incident active TB (Case) were matched with 11,655 patients without TB (control) by age, sex, year of ESRD onset, Charlson comorbidity index, chronic obstructive pulmonary disease, and diabetes mellitus, at a 1:5 case-to-control ratio.

RESULTS

Compared with the control group, the Case group had greater nosocomial exposure to index patients with pulmonary TB (2.36 vs. 0.11 month of exposure, p < 0.001). Nosocomial exposure increased active TB risk (adjusted odds ratio [OR; 95% confidence interval, CI]: 1.60 [1.55-1.66] per month of exposure), particularly when the exposure time was either within 6 months before the index case was diagnosed or 6-15 months before the ESRD patient became an incident active TB case. For patients with active TB, cough-related medication prescriptions (proxy for cough symptoms) exponentially increased over 6 months before TB treatment.

CONCLUSION

Nosocomial exposure attributed to delay in the diagnosis of index pulmonary TB is important in TB transmission among patients undergoing regular hemodialysis. Additional studies investigating how TB can be diagnosed and treated early are warranted.

SUMMARY AT A GLANCE

Our study revealed that nosocomial exposure, attributed to delay in pulmonary TB diagnosis, is important in TB transmission among patients undergoing regular hemodialysis. Strategies to diagnose and treat TB early are crucial to infection control, and they warrant further investigations.