The prospective evaluation of the TB strain typing service in England: a mixed methods study.

BACKGROUND: In response to rising TB notification rates in England, universal strain typing was introduced in 2010. We evaluated the acceptability, effectiveness and cost-effectiveness of the TB strain typing service (TB-STS). METHODS: We conducted a mixed-methods evaluation using routine laboratory, clinic and public health data. We estimated the effect of the TB-STS on detection of false positive Mycobacterium tuberculosis diagnoses (2010-2012); contact tracing yield (number of infections or active disease per pulmonary TB case); and diagnostic delay. We developed a deterministic age-structured compartmental model to explore the effectiveness of the TB-STS, which informed a cost-effectiveness analysis. RESULTS: Semi-structured interviews explored user experience. Strain typing identified 17 additional false positive diagnoses. The TB-STS had no significant effect on contact tracing yield or diagnostic delay. Mathematical modelling suggested increasing the proportion of infections detected would have little value in reducing TB incidence in the white UK-born population. However, in the non-white UK-born and non-UK-born populations, over 20 years, if detection of latent infection increases from 3% to 13% per year, then TB incidence would decrease by 11%; reducing diagnostic delay by one week could lead to 25% reduction in incidence. The current TB-STS was not predicted to be cost-effective over 20 years (£95 628/quality-adjusted life-years). Interviews found people had mixed experiences, but identified broader benefits, of the TB-STS. CONCLUSIONS: To reduce costs, improve efficiency and increase effectiveness, we recommend changes to the TB-STS, including discontinuing routine cluster investigations and focusing on reducing diagnostic delay across the TB programme. This evaluation of a complex intervention informs the future of strain typing in the era of rapidly advancing technologies.

Nationwide study on open tibial fractures in the Netherlands: Incidence, demographics and level of hospital care.

OBJECTIVES: Open tibial fractures are relatively common injuries following traffic accidents. The vulnerability of the soft tissues surrounding the tibia increases the susceptibility to complications, including infection and nonunion. To minimize complications, a multidisciplinary, timely approach is crucial. To date, the Dutch incidence and level of hospital treatment remain unknown due to a lack of condition-specific nationwide registries. This study aimed to estimate the incidence and management of open tibial fractures in the Netherlands, providing essential information for public health policymaking and guideline development. METHODS: The 2018 and 2019 Dutch National Hospital Care Basic Registration data, provided by the Dutch Hospital Data Foundation, were utilized to identify all patients admitted to Dutch hospitals with tibial fractures. Incidence rates, patient demographics, primary diagnoses, fracture classification, level of hospital, and length of hospital stays were analyzed using descriptive statistics. RESULTS: 1,079 ICD-10 codes for closed and open tibial fractures were identified in patients that were admitted to a Dutch hospital. Thirty-four percent were classified as open tibial fractures, accounting for an estimated incidence rate of 1.1 per 100,000 person-years (95 % CI 0.97-1.12). When categorized by age, the calculated incidence rate was higher in males for all age categories up until the age of 70. Notably, the overall highest incidence rate was found for females aged 90 and above (6.6 per 100,000 person-years). Open tibial fractures were predominantly treated in general or top clinical hospitals (comprising 69 % of open all tibia fractures). Notably, the minority (31 %) presented at university medical centers, all Level-1 trauma centers, equipped with orthoplastic teams. CONCLUSION: This is the first study to report the nationwide incidence rate of open tibial fractures in the Netherlands; 34 % of tibial fractures were registered as open. Notably, a limited proportion of open tibial fractures underwent treatment within Level-1 trauma centers. Consequently, in the majority of cases, the implementation of an orthoplastic team approach was unattainable. This study underscores the need for more comprehensive data collection to assess and improve the current treatment landscape.

The economic impact of open lower limb fractures in the Netherlands: a cost-of-illness study.

PURPOSE: To estimate the one-year sum of direct costs related to open lower limb fracture treatment in an academic setting in the Netherlands. The secondary objective was to estimate the impact of deep infection and nonunion on one-year total direct costs. METHODS: A multi-center, retrospective cost analysis of open lower limb fractures treated in an academic setting in the Netherlands, between 1 January 2017 and 31 December 2018, was conducted. The costing methodology was based on patient level aggregation using a bottom-up approach. A multiple linear regression model was used to predict the total costs based on Fracture-related-infections, multitrauma, intensive care unit (ICU) admission, Gustilo-Anderson grade and nonunion. RESULTS: Overall, 70 fractures were included for analysis, the majority Gustilo-Anderson grade III fractures (57%). Median (IQR) one-year hospital costs were €31,258 (20,812-58,217). Costs were primarily attributed to the length of hospital stay (58%) and surgical procedures (30%). The median length of stay was 16 days, with an increase to 50 days in Fracture-related infections. Subsequent costs (46,075 [25,891-74,938] vs. 15,244 [8970-30,173]; p = 0.002), and total hospital costs (90,862 [52,868-125,004] vs. 29,297 [21,784-40,677]; p < 0.001) were significantly higher for infected cases. It was found that Fracture-related infection, multitrauma, and Gustilo-Anderson grade IIIA-C fractures were significant predictors of increased costs. CONCLUSION: In treatment of open lower limb fractures, deep infection, higher Gustilo-Anderson classification, and multitrauma significantly increase direct hospital costs. Considering the impact of infection on morbidity and total healthcare costs, future research should focus on preventing Fracture-related infections.

Long-term results and patient-reported outcomes after vascularized fibular graft use in the treatment of post-traumatic bone defects of femur shaft and tibia: A retrospective cohort and cross-sectional survey study.

OBJECTIVES: Post-traumatic critical-sized bone defects pose a reconstructive challenge for reconstructive surgeons. The vascularized fibula graft is a well-described treatment for osseous defects of the femur and tibia. This study aimed to assess long-term patient-reported quality of life, the success-, and complication rates in lower extremity reconstruction with vascularized fibula grafts. METHODS: A retrospective cohort of 29 patients who underwent fibula graft reconstruction for critical-sized bone defects after post-traumatic tibial and femoral bone loss between 1990 and 2021 was included. To assess the health-related quality of life and return to work and satisfaction, a cross-sectional survey was performed using the short-form-36, lower extremity functional scale, and a self-made questionnaire including the DN4, satisfaction, and subjective ankle function. RESULTS: The median bone defect size was 8 cm (IQR 9-7 cm). The mental component scores were comparable to the Dutch population norm, whereas the impaired physical function scores were associated with pain (r 0.849, p < 0.001). Neuropathic symptoms were reported in 7 out of 19 patients, and 11 out of 19 patients returned to normal daily activity. All respondents reported positive or neutral scores on overall satisfaction with the recovery. Bone healing was uneventful in 19 out of 29 patients. Union was achieved in 25 out of 29 patients. Persistent nonunion was observed in 4 patients, leading to amputation in 2 patients. CONCLUSION: Vascularized fibula graft use led to high union rates and limb salvage in patients with post-traumatic segmental bone loss of the tibia and femur. Patient satisfaction with the overall recovery was positive; however, functional outcomes remained impaired.

Prevalence of smear-positive tuberculosis in persons aged ≥ 15 years in Bangladesh: results from a national survey, 2007-2009.

The aim of this study was to determine the nationwide prevalence of smear-positive tuberculosis (TB) in Bangladesh. A multi-stage cluster survey of a random sample of persons aged ≥ 15 years was included in 40 clusters (20 urban, 20 rural). Two sputum samples were collected from study participants and tested initially by fluorescence microscopy and confirmed by the Ziehl-Neelsen method. The crude and adjusted prevalence rates and 95% confidence intervals (CIs) were calculated using standard methods. A total of 33 new smear-positive TB cases were detected among 52 098 individuals who participated in the study. The average participation rate was over 80%. The overall crude prevalence of new smear-positive TB in persons aged ≥ 15 years was estimated as 63.3/100 000 (95% CI 43.6-88.9) and the adjusted prevalence was 79.4/100 000 (95% CI 47.1-133.8). TB prevalence was higher in males (n = 24) and in rural areas (n = 20). The prevalence was highest in the 55-64 years age group (201/100 000) and lowest in 15-24 years age group (43.0/100 000). The prevalence was higher in persons with no education (138.6/100 000, 95% CI 78.4-245.0). The overall prevalence of smear-positive TB was significantly lower than the prevalence estimate of the previous nationwide survey in Bangladesh in 1987-1988 (870/100 000).

Health-seeking behaviour among adults with prolonged cough in Vietnam.

OBJECTIVE: To assess health-seeking behaviour among adults with prolonged cough in a population-based, nationally representative sample in Vietnam. METHODS: Cross-sectional survey conducted from September 2006 to July 2007. All inhabitants aged ≥15 years were invited for screening for cough, history of tuberculosis (TB) treatment and chest X-ray (CXR) examination. TB suspects, defined as any survey participant with CXR abnormalities consistent with TB, or productive cough for more than 2 weeks or TB treatment either currently or in the preceding 2 years submitted sputum specimens for smear examination and culture and provided information on health-seeking behaviour in an in-depth interview. RESULTS: Of 94 179 persons participating in the survey, 4.6% had prolonged productive cough. Forty-four percentage of those had sought health care and reported pharmacies (35%), commune health posts (29%), public hospitals (24%) and private physicians (10%) as first point of contact. Only 7% had undergone sputum smear examination. Of TB suspects with prolonged productive cough, 2.9% were diagnosed with TB; 10.2% of these reported smear and 21.9% reported X-ray examination when visiting a health care facility. The average patient delay was 4.1 weeks (95% CI: 3.9-4.4) among cough suspects and 4.0 weeks (95% CI: 3.1-4.9) among TB cases. CONCLUSIONS: In this Vietnamese survey, nearly half of persons with cough for more than 2 weeks had visited a health care provider. The commonest first health facility contacted was the pharmacy. Sputum smears were rarely examined, except in the provincial TB hospital. Our findings highlight the need to improve diagnostic practices by retraining health staff on the performance of sputum examination for TB suspects.

Progress towards tuberculosis elimination: secular trend, immigration and transmission.

This study aimed to determine to what extent tuberculosis trends in the Netherlands depend on secular trend, immigration and recent transmission. Data on patients in the Netherlands Tuberculosis Register in the period 1993-2007 were matched with restriction fragment length polymorphism (RFLP) patterns of Mycobacterium tuberculosis isolates. Index patients were defined as patients with pulmonary tuberculosis whose isolates had RFLP patterns not observed in another patient in the previous 2 yrs. Among 8,330 patients with pulmonary tuberculosis the isolates of 56% of native and 50% of foreign-born patients were clustered. Of these, 5,185 were included in detailed analysis: 1,376 native index patients, 2,822 foreign-born index patients and 987 secondary cases within 2 yrs of diagnosis of the index case. The incidence of native and foreign-born index patients declined by 6% and 2% per year, respectively. The number of secondary cases per index case was 0.24. The decline of native cases contributed most to the overall decline of tuberculosis rates and was largely explained by a declining prevalence of latent infection. Tuberculosis among immigrants was associated with immigration figures. Progress towards elimination of tuberculosis would benefit from intensifying diagnosis and treatment of latent infection among immigrants and global tuberculosis control.

Predictive value for progression to tuberculosis by IGRA and TST in immigrant contacts.

The authors determined the positive predictive value (PPV) for progression to tuberculosis (TB) of two interferon-gamma release assays (IGRAs), QuantiFERON-TB Gold In-tube (QFT-GIT) and T-SPOT.TB, and the tuberculin skin test (TST) in immigrants contacts. Immigrant close contacts of sputum smear-positive TB patients were included when aged > or =16 yrs and their TST result was > or =5 mm 0 or 3 months after diagnosis of the index patient. Contacts were followed for the next 2 yrs for development of TB disease. Of 339 immigrant contacts with TST > or =5 mm, 324 and 299 had valid results of QFT-GIT and T-SPOT.TB, respectively. Nine contacts developed active TB. One patient had not been tested with TST, while another patient had not been tested with QFT-GIT and T-SPOT.TB. The PPV for progression to TB during this period was 9/288 = 3.1% (95% CI 1.3-5.0%) for TST > or =10 mm, 7/184 = 3.8% (95% CI 1.7-5.9%) for TST > or =15 mm, 5/178 = 2.8% (95% CI 1.0-4.6%) for QFT-GIT and 6/181 = 3.3% (95% CI 1.3-5.3%) for T-SPOT.TB. Sensitivity was 100%, 88%, 63% and 75%, respectively. The predictive values of QFT-GIT, T-SPOT.TB and TST for progression to TB disease among immigrant close contacts were comparable.

Interferon-gamma release assays in immigrant contacts and effect of remote exposure to Mycobacterium tuberculosis.

OBJECTIVE: To assess the association between remote exposure to tuberculosis (TB) and results of the tuberculin skin test (TST), and two interferon-gamma release assays (IGRAs)-QuantiFERON-TB Gold In-Tube (QFT-GIT) and T-SPOT.TB-in immigrant contacts of sputum smear-positive TB patients. METHODS: Immigrants aged >or=16 years in close contact with smear-positive TB patients were included. QFT-GIT and T-SPOT.TB were performed if the TST induration size was >or=5 mm. Associations between test results and origin from an endemic country were assessed. RESULTS: Of 433 close contacts, 322 (74%) had TST >or=5 mm, of whom, 282 (88%) had valid test results for all assays. Positive QFT-GIT results were obtained for 152/282 (54%) and positive T-SPOT.TB for 168/282 (60%). After adjustment for age, sex and recent contact, positive IGRA results and TST results >/=10 mm were found to be more frequent among immigrants who originated from Africa, in particular sub-Saharan Africa. CONCLUSION: When IGRAs are used to determine latent TB infection in foreign-born individuals, positive findings not only relate to recent TB infection, but also reflect prior TB exposure in the country of origin. This late reactivity will limit their usefulness in contact investigations among immigrants originating from endemic areas.

The Beijing genotype is associated with young age and multidrug-resistant tuberculosis in rural Vietnam.

BACKGROUND: Associations between multidrug resistance and the Mycobacterium tuberculosis Beijing genotype have been described mainly in populations with poor tuberculosis (TB) control such as prisons and inner cities, and may reflect shared risk factors rather than a biological association. OBJECTIVE: To study the association between genotype and drug resistance among TB patients in a population with adequate TB control. SETTING: Three rural districts in Vietnam. The study was performed at the Pham Ngoc Thach Tuberculosis and Lung Disease Hospital, Ho Chi Minh City, and the Tien Giang Provincial Tuberculosis and Lung Disease Hospital, My Tho, Vietnam. METHODS: Pretreatment sputum specimens were collected for culture, drug susceptibility testing and spoligotyping of all sputum smear-positive pulmonary TB patients consecutively diagnosed over a 3-year period. RESULTS: Beijing genotype infections were observed in 614 of 1744 (35%) patients. Beijing strains were more common among female (adjusted odds ratio [aOR] 1.4, P = 0.005), young (aOR 2.8, P < 0.001) and previously treated patients (aOR 2.4, P < 0.001). The Beijing genotype was associated with any resistance (aOR 3.7, P < 0.001) and multidrug resistance (aOR 6.8, P < 0.001) among new patients, and with any resistance (aOR 2.7, P = 0.005) but not with multidrug resistance (aOR 1.4, P = 0.545) among previously treated patients. CONCLUSION: In Vietnam, Beijing genotype is associated with young age and in new patients with multidrug resistance despite adequate TB control, suggesting a biological association. This potentially undermines the effectiveness of TB control in countries where Beijing genotype infections are common.

Annual meeting of the Tuberculosis Surveillance and Research Unit, 2008.

The Tuberculosis Surveillance and Research Unit (TSRU) held its last annual meeting in Helsinki, Finland, from 1 to 4 April 2008. Several topics of current interest for tuberculosis (TB) research and new research projects were presented and discussed in depth by 60 delegates from Europe, Africa and Asia. This paper summarises some of the highlights of the meeting which may be of interest to epidemiologists and managers active in the field of TB.

Informed patient consent for defaulter tracing: should we obtain it?

Active default tracing is an integral part of tuberculosis (TB) programmatic control. It can be differentiated into the tracing of defaulters (patients not seen at the clinic for > or =2 months) and 'late patients' (late for their scheduled appointments). Tracing is carried out to obtain reliable information about who has truly died, transferred out or stopped treatment, and, if possible, to persuade those who have stopped treatment to resume. This is important because, unlike routine care for non-communicable diseases, TB has the potential for transmission to other members of the community, and therefore presents the issue of the rights of the individual over the rights of the community. For this reason, default or 'late patient' tracing (defined together as default tracing in this article) has been incorporated into standard practice in most TB programmes and, in many industrialised countries, it is also a part of public health legislation. In resource-poor countries with limited access to phones or e-mails, default tracing involves active home visits. In this Unresolved Issues article, we discuss the need for patient consent within both the programmatic and the research context; we describe how this subject arose during operational research training at the Research Institute of Tuberculosis in Japan; we provide comments from individuals who are experienced and skilled at international and national TB control; and finally we offer some conclusions about the way forward. This is not an easy subject, and we welcome open debate on the issue.

Lessons learned from community-based tuberculosis case-finding in western Kenya.

SETTING: Although Kenya has a high burden of tuberculosis (TB), only 46% of cases were diagnosed in 2016. OBJECTIVE: To identify strategies for increasing attendance at community-based mobile screening units. DESIGN: We analysed operational data from a cluster-randomised trial, which included community-based mobile screening implemented during February 2015-April 2016. Community health volunteers (CHVs) recruited individuals with symptoms from the community, who were offered testing for human immunodeficiency virus (HIV) and sputum collection for Xpert® MTB/RIF testing. We compared attendance across different mobile unit sites using Wilcoxon rank-sum test. RESULTS: A total of 1424 adults with symptoms were screened at 25 mobile unit sites. The median total attendance among sites was 54 (range 6-134, interquartile range [IQR] 24-84). The median yields of TB diagnoses and new HIV diagnoses were respectively 2.4% (range 0.0-16.7, IQR 0.0-5.3) and 2.5% (range 0.0-33.3, IQR 1.2-4.2). Attendance at urban sites was variable; attendance at rural sites where CHVs were paid a daily minimum wage was significantly higher than at rural sites where CHVs were paid a nominal monthly stipend (P < 0.001). CONCLUSION: Mobile units were most effective and efficient when implemented as a single event with community health workers who are paid a daily wage.

Optimizing the efficiency of tuberculosis active case-finding in health facilities and communities.

SETTING: Efficient tuberculosis (TB) active case-finding strategies are important in settings with high TB burdens and limited resources, such as those in western Kenya.OBJECTIVE: To guide efforts to optimize screening efficiency, we identified the predictors of TB among people screened in health facilities and communities.DESIGN: During February 2015-June 2016, adults aged ≥15 years reporting any TB symptom were identified in health facilities and community mobile screening units, and evaluated for TB. We assessed the predictors of TB using a modified Poisson regression with generalized estimating equations to account for clustering according to screening site.RESULTS: TB was diagnosed in 484 (20.3%) of 2394 symptomatic adults in health facilities and 39 (3.4%) of 1424 in communities. In health facilities, >10% of symptomatic adults in all demographic groups had TB, and no predictors were associated with a ≥2-fold increased risk. In communities, the independent predictors of TB were male sex (adjusted prevalence ratio [aPR] = 4.26, 95%CI 2.43-7.45), HIV infection (aPR 2.37, 95%CI 1.18-4.77), and household TB contact in the last 2 years (aPR 2.84, 95%CI 1.62-4.96).CONCLUSION: Our findings support the notion of general TB screening in health facilities and evaluation of the adult household contacts of TB patients.

Coverage and yield of entry and follow-up screening for tuberculosis among new immigrants.

The aim of the present study was to determine the effectiveness of entry screening for tuberculosis and biannual follow-up screening among new immigrants in The Netherlands. To achieve this, the present authors analysed screening, prevalence and incidence data of 68,122 immigrants, who were followed for 29 months. Patients diagnosed within 5 months and 6-29 months after entry screening were considered to be detected at entry and during the follow-up period, respectively. Coverage of the second to fifth screening rounds was 59, 46, 36 and 34%, respectively. Yield of entry screening was 119 per 100,000 individuals, and prevalence at entry was 131 per 100,000. Average yield of follow-up screening was highest among immigrants with abnormalities on chest radiography (CXR) at entry (902 per 100,000 individuals). When excluding these, yield of follow-up screening was 9, 37 and 97 per 100,000 screenings for immigrants from countries with tuberculosis incidences of <100, 100-200 and >200 per 100,000, respectively. The incidence during follow-up in individuals with a normal CXR was 11, 58 and 145 per 100,000 person-yrs follow-up in these groups. The proportion of cases detected through screening declined per screening round from 91 to 31%. Yield of entry screening was high. Overall coverage and yield of follow-up screening was low. Follow-up screening of immigrants with a normal chest radiograph from countries with an incidence of <200 per 100,000 individuals was therefore discontinued.

How to identify tuberculosis cases in a prevalence survey.

The identification of pulmonary tuberculosis (TB) cases in a prevalence survey is a challenge, as diagnostic methods are labour-intensive and large numbers of individuals need to be screened because the prevalence rate is low (almost never greater than 1,200 per 100,000 population). Three testing methods are used: questionnaires, chest radiography (CXR) and bacteriological tests, including sputum smear microscopy and culture. These methods can be applied in four strategies to identify cases. The most sensitive strategy is to apply all methods to each eligible individual. The next most sensitive option is to apply the questionnaire, CXR and sputum smear microscopy to each eligible individual and obtain sputum for culture from those individuals with symptoms, abnormalities on the CXR or a positive smear. If laboratory capacity is limited, screening using symptom enquiry and CXR can be used to select those individuals at highest risk of TB. These individuals are then requested to submit sputum for smear microscopy and culture. If neither CXR nor culture is available, sputum samples may be collected from all eligible individuals and examined by an enhanced microscopy method such as fluorescence microscopy. Case definitions are ideally based on the combined results of symptom enquiry, CXR and bacteriology.

The design effect and cluster samples: optimising tuberculosis prevalence surveys.

Cross-sectional surveys of disease prevalence, including for tuberculosis (TB), often use a two (or more) stage sampling procedure. By choosing clusters of people randomly from all possible clusters, the logistic costs of doing the survey can be reduced. However, this increases the statistical uncertainty in the estimate of prevalence, and we need to balance the reduction in cost against the increase in uncertainty. Here we describe cluster sampling and consider ways to determine the optimal survey design as well as the extent to which deviations from the optimal design matter. We illustrate the results using data from a recent survey in Cambodia in which TB was diagnosed using sputum smears, cultures and X-rays.

Tuberculosis prevalence surveys: rationale and cost.

This article is the first of the educational series 'Assessing tuberculosis (TB) prevalence through population-based surveys'. The series will give overall guidance in conducting cross-sectional surveys of pulmonary TB (PTB) disease. TB prevalence surveys are most valuable in areas where notification data obtained through routine surveillance are of unproven accuracy or incomplete, and in areas with an estimated prevalence of bacteriologically confirmed TB of more than 100 per 100,000 population. To embark on a TB prevalence survey requires commitment from the national TB programme, compliance in the study population, plus availability of trained staff and financial resources. The primary objective of TB prevalence surveys is to determine the prevalence of PTB in the general population aged >or=15 years. Limitations of TB prevalence surveys are their inability to assess regional or geographic differences in prevalence of TB, estimate the burden of childhood TB or estimate the prevalence of extra-pulmonary TB. The cost of a prevalence survey is typically US$ 4-15 per person surveyed, and up to US$ 25 per person with radiographic screening. A survey of 50,000 people, of limited precision, would typically cost US$ 200,000-1,250,000.

Payment for antiretroviral drugs is associated with a higher rate of patients lost to follow-up than those offered free-of-charge therapy in Nairobi, Kenya.

This retrospective analysis of routine programme data from Mbagathi District Hospital, Nairobi, Kenya shows the difference in rates of loss to follow-up between a cohort that paid 500 shillings/month (approximately US$7) for antiretroviral drugs (ART) and one that received medication free of charge. A total of 435 individuals (mean age 31.5 years, 65% female) was followed-up for 146 person-years: 265 were in the 'payment' cohort and 170 in the 'free' cohort. The incidence rate for loss to follow-up per 100 person-years was 47.2 and 20.5, respectively (adjusted hazard ratio 2.27, 95% CI 1.21-4.24, P=0.01). Overall risk reduction attributed to offering ART free of charge was 56.6% (95% CI 20.0-76.5). Five patients diluted their ART regimen to one tablet (instead of two tablets) twice daily in order to reduce the monthly cost of medication by half. All these patients were from the payment cohort. Payment for ART is associated with a significantly higher rate of loss to follow-up, as some patients might be unable to sustain payment over time. In resource-limited settings, ART should be offered free of charge in order to promote treatment compliance and prevent the emergence of drug resistance.

[Estimation of the incidence of tuberculosis in The Netherlands in 2030]. / Projectie van het aantal tuberculosepatiënten in Nederland in 2030.

OBJECTIVE: To estimate the number of cases of tuberculosis (TB) in 2030 for the purpose of planning future TB control. DESIGN: Statistical modelling in 5-year intervals until 2030. METHOD: The number of Dutch TB cases infected by a Dutch source was estimated using a survival model. The number ofnon-Dutch patients was estimated by calculating the proportion of culture-positive TB patients among first-generation immigrants in 2005 and applying this proportion to the projected size of the non-Dutch population. It was assumed that each non-Dutch TB patient infected by a non-Dutch source would cause one infection in the population in The Netherlands. RESULTS: The estimated number of TB cases is expected to decrease to 877 in 2010. Only a limited decrease in the number of TB patients is expected after 2010 as the number of non-Dutch TB cases increases due to increased immigration. This increase negates the expected decrease in Dutch TB patients infected by a Dutch source. In 2030, non-Dutch TB cases will account for 85% of all TB cases. The proportion of non-Dutch TB cases is greater in the 4 largest cities, i.e. Amsterdam, Rotterdam, The Hague and Utrecht (89%) than in the rest of The Netherlands (76%). CONCLUSION: The decrease in TB incidence observed over the past several years may cease by 2010 due to an increase in non-Dutch TB patients as a result of increased immigration. However, the confidence intervals associated with these estimates were large. Future TB control efforts must be organised in a flexible way so that they can be adapted to changing epidemiological situations.