Table 3

Summary of the effectiveness measures included, costs incurred, quality-adjusted life-years (QALYs) gained and resulting incremental cost effectiveness ratio (ICER) for screening contacts of the indicated index cases compared to a baseline of not screening those contacts

Quantity (units, if applicable)ETB indexesPTB indexes
Embedded Image Embedded Image Embedded Image Embedded Image Embedded Image Embedded Image
Reduction in time contacts are symptomatic (years)2.58 (0.66 to 8.59)2.58 (0.66 to 8.59)2.58 (0.66 to 8.59)10.5 (4.02 to 26.4)10.5 (4.02 to 26.4)10.5 (4.02 to 26.4)
Cases prevented by administering PT (cases)5.45 (3.71 to 7.59)5.45 (3.71 to 7.59)5.45 (3.71 to 7.59)18.9 (13.1 to 25.8)18.9 (13.1 to 25.8)18.9 (13.1 to 25.8)
Transmission reduced by finding contacts sooner (cases)0.0 (0.0 to 0.0)1.71 (0.584 to 3.33)3.41 (1.17 to 6.62)0.0 (0.0 to 0.0)8.76 (3.56 to 14.9)17.5 (7.02 to 29.8)
Transmission reduced from prevented cases (cases)0.0 (0.0 to 0.0)1.62 (0.772 to 3.11)5.19 (2.08 to 12.2)0.0 (0.0 to 0.0)8.63 (4.77 to 14.7)33.1 (16.1 to 66.7)
Reduction in mortality (deaths)0.431 (0.238 to 0.977)0.551 (0.303 to 1.14)0.743 (0.408 to 1.45)1.64 (0.997 to 3.08)2.27 (1.36 to 3.94)3.47 (2.04 to 5.89)
Total case-equivalents averted11.9 (6.56 to 26.9)15.2 (8.34 to 31.4)20.5 (11.2 to 39.9)45.0 (27.5 to 85.0)62.4 (37.5 to 109.0)95.6 (56.2 to 162.0)
Total QALYs gained10.6 (5.98 to 23.4)13.7 (7.66 to 27.6)18.7 (10.4 to 35.6)39.9 (24.8 to 73.9)56.3 (34.2 to 95.9)87.5 (51.7 to 148.0)
Total costs incurred (£000 000 s)1.07 (1.03 to 1.12)1.06 (1.02 to 1.11)1.05 (1.01 to 1.1)1.74 (1.67 to 1.82)1.71 (1.63 to 1.78)1.63 (1.52 to 1.72)
Incremental cost-effectiveness ratio (£000 s/QALY)101.0 (46.2 to 178.0)77.7 (38.8 to 139.0)56.4 (29.3 to 102.0)43.7 (23.7 to 70.1)30.3 (17.7 to 50.1)18.7 (10.5 to 32.7)
Probability the ICER is less than £30 000/QALY0.09%0.260%3.08%14.8%54.0%95.6%
Probability the ICER is less than £20 000/QALY0.00%0.01%0.02%0.42%7.26%64.7%
Threshold which the ICER is 80% probable to be below (£000 s/QALY)13599.671.954.036.622.9
  • Numbers are given for a year with a caseload that is the average caseload of the years 2012–2015 (ie, 2790 cases); note that the caseload does not affect the ICER. No discounting was applied; see online supplementary appendix part 5 for a discussion of discounting. Case-equivalents averted refers to both cases averted, and the reduction in the time contacts are symptomatic divided by the mean symptomatic period of TB cases.

  • Numbers in brackets indicate the 95% CI.

  • r , the number of infections generated by a pulmonary contact per month infectious; ETB, non-pulmonary, non-laryngeal TB; PT, preventive therapy (3 months of isoniazid and rifampicin); PTB, pulmonary or laryngeal TB.