Clinical standards for drug-susceptible pulmonary TB.

BACKGROUND: The aim of these clinical standards is to provide guidance on 'best practice´ for diagnosis, treatment and management of drug-susceptible pulmonary TB (PTB).METHODS: A panel of 54 global experts in the field of TB care, public health, microbiology, and pharmacology were identified; 46 participated in a Delphi process. A 5-point Likert scale was used to score draft standards. The final document represents the broad consensus and was approved by all 46 participants.RESULTS: Seven clinical standards were defined: Standard 1, all patients (adult or child) who have symptoms and signs compatible with PTB should undergo investigations to reach a diagnosis; Standard 2, adequate bacteriological tests should be conducted to exclude drug-resistant TB; Standard 3, an appropriate regimen recommended by WHO and national guidelines for the treatment of PTB should be identified; Standard 4, health education and counselling should be provided for each patient starting treatment; Standard 5, treatment monitoring should be conducted to assess adherence, follow patient progress, identify and manage adverse events, and detect development of resistance; Standard 6, a recommended series of patient examinations should be performed at the end of treatment; Standard 7, necessary public health actions should be conducted for each patient. We also identified priorities for future research into PTB.CONCLUSION: These consensus-based clinical standards will help to improve patient care by guiding clinicians and programme managers in planning and implementation of locally appropriate measures for optimal person-centred treatment for PTB.

[Tuberculosis among asylum-seekers in the Netherlands: a descriptive study among the two largest groups of asylum-seekers]. / Tuberculose bij asielzoekers in Nederland: descriptief onderzoek onder de 2 grootste groepen asielzoekers.

OBJECTIVE: To investigate the prevalence and incidence of tuberculosis (TB) among the two largest groups of asylum-seekers in the Netherlands, i.e. Syrians and Eritreans/Ethiopians. DESIGN: Descriptive study. METHOD: We collected data from the screening of Syrian and Eritrean/Ethiopian asylum-seekers for the period January 2013 - September 2015 and linked these to notifications in the Netherlands Tuberculosis Register. RESULTS: Asylum-seekers from Syria and Eritrea/Ethiopia represented 65% and 72% of all asylum applications in 2014 and in the first nine months of 2015 respectively. Fourteen Syrian asylum-seekers applying during the study period were diagnosed with tuberculosis. The prevalence was 22 cases per 100,000 persons screened upon arrival (95% CI: 10-44), while the incidence within the first year after arrival was 19 per 100,000 persons (95% CI: 3-62). Tuberculosis was diagnosed in 133 Eritrean/Ethiopian asylum-seekers applying during the study period. The prevalence was 283 cases per 100,000 persons screened upon arrival (95% CI: 198-393) and the incidence in the first year after arrival was 1394 per 100,000 persons (95% CI: 1095-1751). CONCLUSION: In the last two years, most asylum-seekers have originated from Syria and among them tuberculosis is relatively uncommon. However, among Eritrean/Ethiopian asylum-seekers, prevalence and incidence in the first year in the Netherlands are high. This suggests that many of them have been recently infected, in their country of origin or during the journey. Other interventions are required, such as screening for latent infection, to prevent tuberculosis among high-risk asylum-seekers and further reduce the incidence of this disease in the Netherlands.

Factors associated with the high tuberculosis case rate in an urban area.

SETTING: The Rotterdam region, the Netherlands, 1995-2006. OBJECTIVE: To identify factors associated with the high tuberculosis (TB) case rate in an urban area. DESIGN: Municipalities were divided into urban and semi-urban/rural municipalities. We compared the characteristics of TB cases and stratified case rates according to age group, immigrant status and place and time of infection between the two areas. RESULTS: The TB case rate in urban municipalities was 3.8-fold higher than in semi-urban/rural municipalities. After stratification for country of birth, the rate ratios were lower (1.7 for immigrants and 2.8 for non-immigrants). Immigrants had most frequently acquired their infection abroad (47% of urban and 62% of semi-urban/rural immigrant cases). In 40% of urban cases and 27% of semi-urban/rural cases, the infection was recently acquired in the Netherlands, translating into a 5.7-fold higher recent transmission case rate for the urban population. CONCLUSIONS: The high urban TB case rate was related to the high proportion of urban immigrants who frequently reactivated an infection acquired abroad. Recent transmission also contributed to a substantial part of the TB caseload in urban municipalities among both urban immigrants and non-immigrants. The authors propose a package of targeted interventions to address the identified factors associated with the high urban TB case rate.

Transmission classification model to determine place and time of infection of tuberculosis cases in an urban area.

We conducted a population-based study in the Rotterdam region of The Netherlands to determine the place and time of infection of tuberculosis (TB) cases using conventional epidemiological and genotyping information. In particular, we focused on the extent of misclassification if genotyping was not combined with epidemiological information. Cases were divided into those with a unique mycobacterial DNA fingerprint, a clustering fingerprint, and an unknown fingerprint. We developed transmission classification trees for each category to determine whether patients were infected in a foreign country or recently (2 years) infected in The Netherlands. Of all TB cases during the 12-year study period, 38% were infected in a foreign country, 36% resulted from recent transmission in The Netherlands, and 18% resulted from remote infection in The Netherlands, while in the remaining cases (9%) either the time or place of infection could not be determined. The conventional epidemiological data suggested that at least 29% of clustered cases were not part of recent chains of transmission. Cases with unknown fingerprints, almost all culture negative, relatively frequently had confirmed epidemiological links with a recent pulmonary TB case in The Netherlands and were more often identified by contact tracing. Our findings highlight the idea that genotyping should be combined with conventional epidemiological investigation to establish the place and time of infection of TB cases as accurately as possible. A standardized way of classifying TB into recently, remotely, and foreign-acquired disease provides indicators for surveillance and TB control program performance that can be used to decide on interventions and allocation of resources.

Record-linkage and capture-recapture analysis to estimate the incidence and completeness of reporting of tuberculosis in England 1999-2002.

In 1999 the Enhanced Tuberculosis Surveillance (ETS) system was introduced in the United Kingdom to strengthen surveillance of tuberculosis (TB). The aim of this study was to assess the use of record-linkage and capture-recapture methodology for estimating the completeness of TB reporting in England between 1999 and 2002. Due to the size of the TB data sources sophisticated record-linkage software was required and the proportion of false-positive cases among unlinked hospital-derived TB records was estimated through a population mixture model. This study showed that record-linkage of TB data sources and cross-validation with additional TB-related datasets improved data quality as well as case ascertainment. Since the introduction of ETS observed completeness of notification in England has increased and the results were consistent with expected levels of under-notification. Completeness of notification estimated by a log-linear capture-recapture model was highly inconsistent with prior estimates and the validity of this methodology was further examined.

Incidence and completeness of notification of Legionnaires' disease in The Netherlands: covariate capture-recapture analysis acknowledging regional differences.

To estimate incidence and completeness of notification of Legionnaires' disease (LD) in The Netherlands in 2000 and 2001, we performed a capture-recapture analysis using three registers: Notifications, Laboratory results and Hospital admissions. After record-linkage, 373 of the 780 LD patients identified were notified. Ascertained under-notification was 52.2%. Because of expected and observed regional differences in the incidence rate of LD, alternatively to conventional log-linear capture-recapture models, a covariate (region) capture-recapture model, not previously used for estimating infectious disease incidence, was specified and estimated 886 LD patients (95% confidence interval 827-1022). Estimated under-notification was 57.9%. Notified, ascertained and estimated average annual incidence rates of LD were 1.15, 2.42 and 2.77/100 000 inhabitants respectively, with the highest incidence in the southern region of The Netherlands. Covariate capture-recapture analysis acknowledging regional differences of LD incidence appears to reduce bias in the estimated national incidence rate.

Estimating infectious diseases incidence: validity of capture-recapture analysis and truncated models for incomplete count data.

Capture-recapture analysis has been used to evaluate infectious disease surveillance. Violation of the underlying assumptions can jeopardize the validity of the capture-recapture estimates and a tool is needed for cross-validation. We re-examined 19 datasets of log-linear model capture-recapture studies on infectious disease incidence using three truncated models for incomplete count data as alternative population estimators. The truncated models yield comparable estimates to independent log-linear capture-recapture models and to parsimonious log-linear models when the number of patients is limited, or the ratio between patients registered once and twice is between 0.5 and 1.5. Compared to saturated log-linear models the truncated models produce considerably lower and often more plausible estimates. We conclude that for estimating infectious disease incidence independent and parsimonious three-source log-linear capture-recapture models are preferable but truncated models can be used as a heuristic tool to identify possible failure in log-linear models, especially when saturated log-linear models are selected.

Estimating the coverage of a targeted mobile tuberculosis screening programme among illicit drug users and homeless persons with truncated models.

Truncated models are indirect methods to estimate the size of a hidden population which, in contrast to the capture-recapture method, can be used on a single information source. We estimated the coverage of a tuberculosis screening programme among illicit drug users and homeless persons with a mobile digital X-ray unit between 1 January 2003 and 31 December 2005 in Rotterdam, The Netherlands, using truncated models. The screening programme reached about two-third of the estimated target population at least once annually. The intended coverage (at least two chest X-rays per person per year) was about 23%. We conclude that simple truncated models can be used relatively easily on available single-source routine data to estimate the size of a population of illicit drug users and homeless persons. We assumed that the most likely overall bias in this study would be overestimation and therefore the coverage of the targeted mobile tuberculosis screening programme would be higher.

Completeness of notification of tuberculosis in The Netherlands: how reliable is record-linkage and capture-recapture analysis?

The aim of this study was to describe a systematic process of record-linkage, cross-validation, case-ascertainment and capture-recapture analysis to assess the quality of tuberculosis registers and to estimate the completeness of notification of incident tuberculosis cases in The Netherlands in 1998. After record-linkage and cross-validation 1499 tuberculosis patients were identified, of whom 1298 were notified, resulting in an observed under-notification of 13.4%. After adjustment for possible imperfect record-linkage and remaining false-positive hospital cases observed under-notification was 7.3%. Log-linear capture-recapture analysis initially estimated a total number of 2053 (95% CI 1871-2443) tuberculosis cases, resulting in an estimated under-notification of 36.8%. After adjustment for possible imperfect record-linkage and remaining false-positive hospital cases various capture-recapture models estimated under-notification at 13.6%. One of the reasons for the higher than expected estimated under-notification in a country with a well-organized system of tuberculosis control might be that some tuberculosis cases, e.g. extrapulmonary tuberculosis, are managed by clinicians less familiar with notification of infectious diseases. This study demonstrates the possible impact of violation of assumptions underlying capture-recapture analysis, especially the perfect record-linkage, perfect positive predictive value and absent three-way interaction assumptions.

[An outbreak of multiresistant tuberculosis from Eastern Europe in the Netherlands]. / Een uitbraak van multiresistente tuberculose uit Oost-Europa in Nederland.

Infectious multiresistant pulmonary tuberculosis was diagnosed in a 24-year-old woman from an Eastern European country who resided in the Netherlands illegally. Her chest X-ray showed extensive cavitating lesions in both lungs. The patient was infectious for a long time and contact investigation revealed 2 other cases of multiresistant tuberculosis, her boyfriend aged 39 and his father, aged 58 years. Transmission from the index case was confirmed by DNA fingerprinting. Seven contacts had a latent tuberculosis infection. All 3 tuberculosis patients were successfully treated, while a number of the infected contacts received preventive treatment. Multiresistant tuberculosis is on the rise in Eastern Europe. It is a serious disease with a high mortality rate despite treatment and has considerable social implications. This outbreak emphasises the necessity of maintaining an efficient tuberculosis control network in low incidence countries, such as the Netherlands. This is the first time an outbreak of multiresistant tuberculosis of this magnitude is described in the Netherlands.

Underreporting of malaria incidence in The Netherlands: results from a capture-recapture study.

The aim of this study was to estimate the completeness of notification of malaria by physicians and laboratories in the Netherlands in 1996. We used a capture-recapture (CRC) analysis of three incomplete, partially overlapping registers of malaria cases: a laboratory survey, the Notification Office and the hospital admission registration. The response of the laboratories was 83.2%. In 1996 the laboratories microscopically identified 535 cases of malaria, 330 patients with malaria were admitted to hospital and physicians notified 311 malaria cases. 667 malaria cases were recorded in at least one register. CRC analysis estimated the total number of malaria cases at 774 (95 % CI of 740-821). This implies a completeness of notification of 40.2% for physicians and 69.1% for the laboratories. It can be concluded that laboratory-based notification can considerably increase the number of officially reported malaria cases as compared to notification by physicians. However, possibly one-third of the cases may still go unreported.