Population study on diagnosis, treatment and outcomes of critically ill patients with tuberculosis (2008-2018).

BACKGROUND: Tuberculosis (TB) is a preventable and curable disease, but mortality remains high among those who develop sepsis and critical illness from TB. METHODS: This was a population-based, multicentre retrospective cohort study of patients admitted to all 15 publicly funded Hong Kong adult intensive care units (ICUs) between 1 April 2008 and 31 March 2019. 940 adult critically ill patients with at least one positive Mycobacterium tuberculosis (MTB) culture were identified out of 133 858 ICU admissions. Generalised linear modelling was used to determine the impact of delay in TB treatment on hospital mortality. Trend of annual Acute Physiology and Chronic Health Evaluation (APACHE) IV-adjusted standardised mortality ratio (SMR) over the 11-year period was analysed by Mann-Kendall's trend test. RESULTS: ICU and hospital mortality were 24.7% (232/940) and 41.1% (386/940), respectively. Of those who died in the ICU, 22.8% (53/232) never received antituberculosis drugs. SMR for ICU patients with TB remained unchanged over the study period (Kendall's τb=0.37, p=0.876). After adjustment for age, Charlson comorbidity index, APACHE IV, albumin, vasopressors, mechanical ventilation and renal replacement therapy, delayed TB treatment was directly associated with hospital mortality. In 302/940 (32.1%) of patients, TB could only be established from MTB cultures alone as Ziehl-Neelsen staining or PCR was either not performed or negative. Among this group, only 31.1% (94/302) had concurrent MTB PCR performed. CONCLUSIONS: Survival of ICU patients with TB has not improved over the last decade and mortality remains high. Delay in TB treatment was associated with higher hospital mortality. Use of MTB PCR may improve diagnostic yield and facilitate early treatment.

A strong tuberculin reaction in primary school children predicts tuberculosis in adolescence.

BACKGROUND: In Hong Kong, neonatal bacillus Calmette-Guerin vaccination coverage has been around 99% since 1970. Children younger than 14 years of age appear to have a relatively low risk of tuberculosis (TB), but the risk of TB increases rapidly after 15 years of age to a secondary peak in young adulthood. METHODS: We followed prospectively 19,383 students who were 6 to 10 years of age participating in the 1999/2000 bacillus Calmette-Guerin revaccination program by cross-matching with the territory-wide TB registry until December 31, 2010, using the identity card number as a unique identifier. RESULTS: After 214,753 person-years of follow-up, 44 active TB cases (22 culture-confirmed) were detected for an overall incidence of 20.5/100,000 person-years. The incidence differed significantly by baseline tuberculin reaction sizes (13.0, 18.8, 22.5, 280.4 per 100,000 person-years for reaction size of 0-4, 5-9, 10-14, and ≥15 mm, respectively, P < 0.001). Consistent results were observed for culture-confirmed cases and after adjustment for gender and baseline age. For those with tuberculin reaction size ≥15 mm, the incidence of TB was significantly higher beyond the age of 15 years than for those less than 15 years (608.1 vs. 37.5 per 100,000 person-years, P < 0.001). Although older baseline age was associated with larger tuberculin reaction sizes, it did not independently predict subsequent development of disease. CONCLUSION: Strong tuberculin reactions in primary school children predicted TB in adolescents after an initial quiescent period. Endogenous reactivation, possibly related to changes in host immunity, might account for the upsurge of TB in adolescence.

A longitudinal study of serial BODE indices in predicting mortality and readmissions for COPD.

INTRODUCTION: BODE index comprises Body mass index, Obstruction of the airway [FEV(1)], Dyspnoea score [modified Medical Research Council questionnaire] and Exercise capacity [6 min walk test]. This study assessed the role of serial changes in BODE index in predicting mortality and readmissions of COPD patients. METHODS: A prospective cohort study involving 243(208 males) COPD patients hospitalized for acute exacerbations of COPD [AECOPD]. BODE index was assessed at 6 weeks(baseline), 6, 12, 18 and 24 months post hospital discharge. Mortality and readmissions in the subsequent 3 years were recorded. All the patients were managed by usual care without additional intervention. RESULTS: The mean (SD) age and FEV(1)% predicted were 74.2(7.8) yrs and 51.7(21.6)% respectively. Over the 3 years, 25.1% died whereas 76.5% had at least 1 readmission for AECOPD. Baseline BODE index was predictive of both the survival and readmissions to hospital for AECOPD by Cox regression analysis (p < 0.001 for both survival and readmissions). Over 24 months, 71(40.1%), 94(53.1%), 12(6.8%) patients had increased (>1 point), no change, and decreased in BODE (>1 point) index respectively. Serial changes in BODE index at 6 month was marginally associated with mortality, but not at 12-, 18- and 24-month. The 6-, 12- and 24-month BODE indices were predictive of the readmissions for AECOPD when compared to baseline. CONCLUSION: Baseline BODE index could predict both survival and readmissions for AECOPD, whereas serial BODE indices were not predictive of survival at 3 years. Single rather than serial measurements of BODE index is sufficient for prediction of survival and readmissions for patients treated with usual care.

T-Spot.TB outperforms tuberculin skin test in predicting tuberculosis disease.

RATIONALE: Silicosis is a well-recognized risk factor for tuberculosis (TB). OBJECTIVES: To compare T-Spot.TB with tuberculin skin test (TST) in predicting the development of TB. METHODS: Male patients with silicosis without clinical suspicion of active TB, past history of TB, and treatment for latent TB infection (LTBI) were offered both T-Spot.TB and TST in the Pneumoconiosis Clinic of Hong Kong from 2004 to 2008, and followed prospectively until September 30, 2009, for development of TB. MEASUREMENTS AND MAIN RESULTS: Active TB and culture- or histology-confirmed TB developed in 17 (5.5%) and 14 (4.5%) of 308 recruited subjects at an annual rate of 2,247 and 1,851 per 100,000 person-years, respectively. Active TB occurred in 7.4% (15 of 204) and 1.9% (2 of 104) of T-Spot.TB-positive and -negative subjects, respectively, whereas the corresponding figures for TST (cutoff 10 mm) were 6.4% (13 of 203) and 3.9% (4 of 205), respectively. A positive T-Spot.TB test significantly predicted the subsequent development of active TB (relative risk, 4.50; 95% confidence interval, 1.03-19.68) and culture- or histology-confirmed TB (relative risk, 7.80; 95% confidence interval, 1.02-59.63). Consistent results were obtained after exclusion of subjects treated for LTBI and adjustment for potential confounders. TST did not significantly predict the development of active TB or culture- or histology-confirmed TB, irrespective of the cutoff values with or without exclusion of subjects treated for LTBI. Culture filtrate protein 10 spot count, but not early secretary antigenic target 6 spot count, was significantly associated with subsequent TB development. CONCLUSIONS: T-Spot.TB performs better than TST in the targeted screening of LTBI among patients with silicosis.