Role of community-based active case finding in screening tuberculosis in Yunnan province of China

Background:The barriers to access diagnosis and receive treatment,in addition to insufficient case identification and reporting,lead to tuberculosis(TB)spreads in communities,especially among hard-to-reach populations.This study evaluated a community-based active case finding(ACF)strategy for the detection of tuberculosis cases among high-risk groups and general population in China between 2013 and 2015.Methods:This retrospective cohort study conducted an ACF in ten communities of Dongchuan County,located in northeast Yunnan Province between 2013 and 2015;and compared to 136 communities that had passive case finding(PCF).The algorithm for ACF was:1)screen for TB symptoms among community enrolled residents by home visits,2)those with positive symptoms along with defined high-risk groups underwent chest X-ray(CXR),followed by sputum microscopy confirmation.TB incidence proportion and the number needed to screen(NNS)to detect one case were calculated to evaluate the ACF strategy compared to PCF,chi-square test was applied to compare the incidence proportion of TB cases'demography and the characteristics for detected cases under different strategies.Thereafter,the incidence rate ratio(IRR)and multiple Fisher's exact test were applied to compare the incidence proportion between general population and high-risk groups.Patient and diagnostic delays for ACF and PCF were compared by Wilcoxon rank sum test.Results:A total of 97521 enrolled residents were visited with the ACF cumulatively,12.3%were defined as highrisk groups or had TB symptoms.Sixty-six new TB patients were detected by ACF.There was no significant difference between the cumulative TB incidence proportion for ACF(67.7/100000 population)and the prevalence for PCF(62.6/100000 population)during 2013 to 2015,though the incidence proportion in ACF communities decreased after three rounds active screening,concurrent with the remained stable prevalence in PCF communities.The cumulative NNS were 34,39 and 29 in HIV/AIDS infected individuals,people with positive TB symptoms and history of previous TB,respectively,compared to 1478 in the general population.The median patient delay under ACF was 1 day(Interquartile range,IQR:0-27)compared to PCF with 30 days(IQR:14-61).Conclusions:This study confirmed that massive ACF was not effective in general population in a moderate TB prevalence setting.The priority should be the definition and targeting of high-risk groups in the community before the screening process is launched.The shorter time interval of ACF between TB symptoms onset and linkage to healthcare service may decrease the risk of TB community transmission.Furthermore,integrated ACF strategy in the National Project of Basic Public Health Service may have long term public health impact.

Active case-finding for tuberculosis by mobile teams in Myanmar:yield and treatment outcomes

Background:Since 2005,the Myanmar National Tuberculosis Programme(NTP)has been implementing active case finding(ACF)activities involving mobile teams in hard-to-reach areas.This study revealed the contribution of mobile team activities to total tuberculosis(TB)case detection,characteristics of TB patients detected by mobile teams and their treatment outcomes.Methods:This was a descriptive study using routine programme data between October 2014 and December 2014.Mobile team activities were a one-stop service and included portable digital chest radiography(CXR)and microscopy of two sputum samples.The algorithm of the case detection included screening patients by symptoms,then by CXR followed by sputum microscopy for confirmation.Diagnosed patients were started on treatment and followed until a final outcome was ascertained.Results:A total of 9349 people with symptoms suggestive of TB were screened by CXR,with an uptake of 96.6%.Of those who were meant to undergo sputum smear microscopy,51.4%had sputum examinations.Finally,504 TB patients were identified by the mobile teams and the overall contribution to total TB case detection in the respective townships was 25.3%.Among total cases examined by microscopy,6.4%were sputum smear positive TB.Treatment success rate was high as 91.8%in study townships compared to national rate 85%(2014 cohort).Conclusions:This study confirmed the feasibility and acceptability of ACF by mobile teams in hard-to-reach contexts,especially when equipped with portable,digital CXR machines that provided immediate results.However,the follow-up process of sputum examination created a significant barrier to confirmation of the diagnosis.In order to optimize the ACF through mobile team activity,future ACF activities were needed to be strengthened one stop service including molecular diagnostics or provision of sputum cups to all presumptive TB cases prior to CXR and testing if CXR suggestive of TB.

Incidence and risk factors of tuberculosis among the elderly population in China:a prospective cohort study

Background:China is facing challenges of the shifting presentation of tuberculosis(TB)from younger to elderly due to an ageing population,longer life expectancy and reactivation disease.However,the burden of elderly TB and influence factors are not yet clear.To fill the gap,we generated a cohort study to measure the magnitude of TB incidence and associated factors among the elderly population aged 65 years and above in China.Methods:In this cohort established in 2013 through a prevalence survey conducted in selected sites,a total of 34076 elderlies without TB were enrolled into two-year follow-up.We used both active and passive case findings to find out all TB patients among them.The person-year(PY)incidence rates for both bacteriologically positive TB and active TB were calculated.Cox proportional regression model was performed to test effect of risk factors,and the population attributable fraction(PAF)of each risk factor contributing to incident TB among elderlies was calculated.Results:Over the two-year follow-up period,a total of 215 incident active TB were identified,62 of which were bacteriologically positive.The incidence rates for active TB and bacteriologically positive TB were 481.8 per 100000 PY(95%CI:417.4–546.2 per 100000 PY)and 138.9 per 100000 PY(95%CI:104.4–173.5 per 100000 PY),respectively.Incident cases detected by active case finding were significantly higher(P<0.001).Male,non-Han nationality,previously treated TB,ex/current smoker and body mass index(BMI)<18.5 presented as independent predictors for developing TB disease.For developing bacteriologically positive TB,the biggest contribution was from self-reported ex or current smoker(18.06%).And,for developing active TB,the biggest contribution was from non-Han nationality(35.40%),followed by male(26.80%)and age at 75 years and above(10.85%).Conclusions:Ageing population in China had a high TB incidence rate and risk to develop TB disease,implying that National TB Program(NTP)needs to prioritize for elderly.Active case finding should be applied capture more active TB cases among this particular population,especially for male,non-Han nationality,and those with identified risk factors.

Evaluating the yield of systematic screening for tuberculosis among three priority groups in Ho Chi Minh City,Viet Nam

Background: In order to end tuberculosis(TB),it is necessary to expand coverage of TB care services,including systematic screening initiatives.However,more evidence is needed for groups among whom systematic screening is only conditionally recommended by the World Health Organization.This study evaluated concurrent screening in multiple target groups using community health workers(CHW).Methods:: In our two-year intervention study lasting from October 2017 to September 2019,CHWs in six districts of Ho Chi Minh City,Viet Nam verbally screened three urban priority groups:(1)household TB contacts;(2)close TB contacts;and(3)residents of urban priority areas without clear documented exposure to TB including hotspots,boarding homes and urban slums.Eligible persons were referred for further screening with chest radiography and follow-on testing with the Xpert MTB/RIF assay.Symptomatic individuals with normal or without radiography results were tested on smear microscopy.We described the TB care cascade and characteristics for each priority group,and calculated yield and number needed to screen.Subsequently,we fitted a mixed-effect logistic regression to identify the association of these target groups and secondary patient covariates with TB treatment initiation.Results: We verbally screened 321020 people including 24232 household contacts,3182 social and close contacts and 293606 residents of urban priority areas.This resulted in 1138 persons treated for TB,of whom 85 were household contacts,39 were close contacts and 1014 belonged to urban priority area residents.The yield of active TB in these groups was 351,1226 and 345 per 100000,respectively,corresponding to numbers needed to screen of 285,82 and 290.The fitted model showed that close contacts[adjusted odds ratio(aOR)=2.07;95%CI:1.38–3.11;P<0.001]and urban priority area residents(aOR=2.18;95%CI:1.69–2.79;P<0.001)had a greater risk of active TB than household contacts.Conclusions: The study detected a large number of unreached persons with TB,but most of them were not among persons in contact with an index patient.Therefore,while programs should continue to optimize screening in contacts,to close the detection gap in high TB burden settings such as Viet Nam,coverage must be expanded to persons without documented exposure such as residents in hotspots,boarding homes and urban slums.