Utility of the plasma level of suPAR in monitoring risk of mortality during TB treatment.

OBJECTIVE: To investigate whether changes in the plasma level of soluble urokinase plasminogen activator receptor (suPAR) can be used to monitor tuberculosis (TB) treatment efficacy. DESIGN: This prospective cohort study included 278 patients diagnosed with active pulmonary TB and followed throughout the 8-month treatment period. RESULTS: Mortality during treatment was higher in the highest inclusion quartile of suPAR (23%) compared to the lowest three quartiles (7%), the risk ratio being 3.1 (95% CI 1.65-6.07). No association between early smear conversion and subsequent mortality or inclusion suPAR was observed. After 1 and 2 months of treatment, an increase in suPAR compared to at diagnosis was associated with a Mortality Rate Ratio (MRR) of 4.5 (95%CI: 1.45-14.1) and 2.1 (95%CI 0.62-6.82), respectively, for the remaining treatment period. CONCLUSIONS: The present study confirmed that elevated suPAR level at time of initiation of TB treatment is associated with increased risk of mortality. Furthermore, increased suPAR levels after one month of treatment was associated with increased risk of mortality during the remaining 7-month treatment period.

High mortality risk among individuals assumed to be TB-negative can be predicted using a simple test.

OBJECTIVES: To determine mortality among assumed TB negative (aTBneg) individuals in Guinea-Bissau and to investigate whether plasma levels of soluble urokinase receptor (suPAR) can be used to determine post-consultation mortality risk. METHODS: This prospective West-African cohort study included 1007 aTBneg individuals who were enrolled from 2004 to 2006; 4983 age-matched controls were followed for comparison. Plasma suPAR levels were measured using the suPARnostic ELISA. Survival was analysed using Cox regression, ROC curves and Kaplan-Meier analysis. RESULTS: After 3 months of follow-up, mortality was 21 per 100 person-year-observation (PYO) among aTBneg individuals and three per 100 PYO among the control population [mortality rate ratio (MRR) = 6.92 (95% CI 4.48-10.7)]. SuPAR values ranged between 0.9 and 45 ng/ml in aTBneg individuals. A log-linear relationship was found between suPAR levels <15 ng/ml and mortality. In the log-linear range, a 1 ng/ml increase was associated with a 46% increase in the mortality rate: MRR = 1.46 (95% CI 1.34-1.59). The area under the ROC curves was 0.88 for HIV-positive individuals and 0.79 for HIV-negative individuals. CONCLUSIONS: Our study showed a high mortality rate among aTBneg individuals and demonstrated that suPAR measurements can provide prognostic information on mortality among individuals without disease diagnosis. Measuring suPAR is a technically simple method for determining mortality risk in individuals that are assumed to be TB-negative.