Table 1 Economic evaluations of latent tuberculosis infection screenings published up to July 2014

Dasgupta et al. (Canada; 2000) [19]

1. Screening (medical evaluation, CXR);

Administrative data bases

CEA

Health care payer

Markov 20 years

Direct

CXR, clinic visits, investigations, hospitalization, drugs, physicians’ and pharmacists’ fees, administrative activities.

• TB case detected: CAN$ 31,418; prevented: CAN$ 73,125;

Close-contact investigation was highly cost-effective and resulted in net savings. Immigrant applicant screening and surveillance programs had a significant impact but were much less cost-effective, in large part because of substantial operational problems. Radiographic screening of newly arriving foreign-born populations for TB could be cost-effective and have considerable individual and public health benefits.

• CAN$ 55,728; CAN$ 155,729;

2. Surveillance of inactive TB, including LTBI treatment;

• CAN$ 10,275; CAN$ 29,668.

3. Close-contact investigation

Khan et al. (USA; 2002) [18]

1. No LTBI screening;

Data bases

CEA, CUA

Societal

Markov Lifetime 3.00%

Health Direct

Transportation, ambulatory care, services of interpreters, laboratory tests, medications, adverse drug reactions, hospitalization, and patients’ time.

Total savings: US$60 to US$90 million, assuming to avert 9–10 thousand TB infections per year.

CEA

Results variable according to country of origin.

• TST followed by INH: savings or dominated, depending on regions.

2. TST followed by INH;

Indirect

A strategy of detecting and treating LTBI was cost-saving among immigrants from Mexico, Haiti, sub-Saharan Africa, South Asia, and developing nations in East Asia and the Pacific.

• TST followed RIF: dominant.

4. TST followed by RIF plus PZM.

• TST followed RIF plus PZM: saving or cost/effective (US$2,551 - US$149,978 per future case averted), depending on regions.

3. TST followed by RIF;

per QALY

Screening was highly cost-effective among immigrants from other developing nations. RIF-PZM was the preferred treatment for treating LTBI in immigrants from Vietnam, Haiti, and the Philippines.

• TST followed by INH: savings, US$914 - US$5,952, or dominated depending on regions.

• TST followed by RIF: dominant.

• TST followed by RIF plus PZM: savings, or US$1,276 - US$53,388, depending on regions.

Brassard et al. (Canada; 2006) [17]

1. LTBI school-screening program in newly arrived immigrant children (TST followed by INH);

Clinical trial^c

CBA

Health care payer

No

Health Direct

Total material and labor costs associated with the school-screening program and the associate investigations for children and associates.

Total savings: CAN$ 363,923.

The school-based LTBI-screening program was found to be cost-effective.

Without associate investigation: CAN$ 268,393.

Savings were mainly due to hospitalization costs.

2. Active TB management through passive case finding.

Porco et al. (USA; 2006) [20]

1. Follow-up of TB-notification patients, including LTBI treatment for latently infected individuals;

Published literature, administrative data bases

CEA, CUA

Health care payer

Markov 20 years 3.00%

Direct

Diagnostic tests, nursing assessments and doctor visits, drugs, side effects, hospitalizations.

The program yielded 7.7 net QALYs, US$ 25,000 in net savings, and prevented 4 cases of TB.

Treatment of TB4s was cost-saving.

Domestic follow up is highly cost-effective as early detection and treatment reduces the rate of hospitalization.

Treatment of TB2s was highly cost-effective: US$4,400 per QALY and US$4,700 per case prevented.

2. No follow-up.

Oxlade O et al. (Canada;2007) [11]

1. CXR;

Published literature, administrative data bases

CEA

Societal

Markov

Health Direct

All government and health system costs, patients’ out-of-pocket expenditures, but not TB-related death or disability.

Savings only in high-very high risk populations:

CXR - the least costly ICER per case prevented: CAN$ 875 for immigrants from high-incidence TB up to CAN$ 2.2 million from low incidence.

Screening with CXR would be the most and QFT the least cost-effective.

2. TST;

20 years

3. QFT;

3.00%

4. TST+QTF;

• CXR - CAN$ 44,710; CAN$ 65,490;

Screening for LTBI, with TST or QFT, is cost-effective only if the risk of disease is high. The most cost-effective use of QFT is to test TST-positive persons.

5. No screening.

QFT - the most expensive: CAN$62,643 up to CAN$1,122,200.

• TST - CAN$ 136260; CAN$ 476320;

TST - better than QFT with saving up to CAN$35,000 compared to QFT, but in populations BCG-vaccinated after infancy, where TST more expensive because of low specificity.

Three scenarios:

• QFT - CAN$ 100,490; CAN$ 440,550.

Screening with TST or QFT was much more cost-effective in contacts than entering immigrants.

a) immigration entry screening;

However, the selection of screening strategy is less important than program performance. Programs considering these new ex vivo tests for LTBI should thus first ensure that a high proportion of those with positive tests will be medically evaluated, prescribed and complete therapy.

b) close or

c) casual contacts.

Hardy et al. (UK; 2010) [21]

1. NICE guidance 2006;

Clinical trial^c

CEA

Health care payer

No

Health Direct

Cost per case LTBI identified

Cost per case identified:

QFT-first protocol can be carried out more cheaply than a CXR-first protocol, with a cost-saving of about 35% (£67.65) compared to NICE protocol. This saving is due to the reduced number of CXRs required.

• NICE protocol: £160.81;

• Leed protocol: £93.16.

2. Leeds protocol: QTF first in immigrants from countries with TB incidence >200/10⁵ followed by CXR (all ages, but mean age was 30.8 year).

Linas et al. (USA; 2011) [23]

1. TST;

Published literature

CEA, CUA

Health care payer

Markov Lifetime 3.00%

Health Direct

Nursing and physician visits, diagnostic tests, medications, hospitalizations, contact tracing, and directly observed therapy.

• Individuals at highest risk of TB reactivation (close contacts and HIV-infected) - ICER of IGRA compared to TST was <$100,000/QALY gained.

In foreign-born subjects IGRA was cost-saving compared to TST and cost-effective compared to no screening.

2. IGRA;

3. No LTBI screening.

Risk-groups^a

• The foreign-born - IGRA was cost-saving compared to TST and cost-effective compared to no screening (ICER <$100,000/ QALY gained).

• Vulnerable populations (homeless, drug user, former prisoner) - ICER of TST screening was approximately $100,000-$150,000/QALY gained, but IGRA was not cost-effective.

• Medical co-morbidities (diabetes and others) - ICER of screening with TST or IGRA was >$100,000/QALY.

Pareek et al. (UK; 2011) [15]

1. QFT;

Clinical trial^c

CEA

Government health care payer

Markov 20 years 3.50%

Direct

UK NICE TB guidelines

Screening of immigrants from any countries irrespective of tuberculosis incidence would cost:

• Screen immigrants aged 16–35 years from countries with incidences/10⁵

Screening for latent infection can be implemented cost-effectively at a level of incidence that identifies most immigrants with latent tuberculosis, thereby preventing substantial numbers of future cases of active tuberculosis.

2. NICE guidance 2006^b.

• QFT more than £1.5 million and prevent 44.5 cases of tuberculosis;

≥250/10⁵: £ 17,956 per case averted; ≥ 150/10⁵: £ 20,819; ≥40/10⁵: £ 29,403.

Screen immigrants aged ≤35 years irrespective of TB incidence: £ 101,938.

• NICE guidance ≈£850,000 and prevent 13.2 cases.

Pareek et al. (UK; 2012) [16]

1. TST+ in <35y old immigrants;

Clinical trial^c

CEA

Government health care payer

Markov 20 years

Direct

Current UK national guidance associated with additional costs of between £594,957 and £1,530,303 over 20 years.

• QFN (single): £21,565 - £34,754 per TB case averted.

Mandatory CXR on arrival could be safely eliminated in order to improve screening cost-effectiveness with single-step QTF at incidence threshold >250/10⁵ per year.

• CXR plus single QFN: £59,489.

2. QTF+ in <35y old immigrants;

• CXR plus single T.SPOT.TB: £402,422.

3. T-SPOT+ in <35y old immigrants.

All with or without CXR port of entry.

Iqbal et al. (USA, 2014) [22]

1. QFT;

Administrative data base (2007)

CEA

Government health care payer

Decision model

Health Direct

Screening, CXR, Treatments, lab tests and diagnostics, physicians’ and staff time.

Total screening cost: TST US$38; QFT-G US$74

Differential costs for screening and follow-up for subjects who were estimated to be test positive on 1,000 latent TB infections

QFT is cost-effective especially for high-risk populations such as foreign-born individuals.

2. TST.

Key assumption.

False positive rates:

• U.S. born

• U.S. born

QFT: +US$25,037 vs. TST.

TST 66%; QFT 40%

• Foreign born

Treatment duration: 9 months

QFT: −US$135,946.

• Foreign born

TST 69%; QFT 18%

Treatment duration: 9 months