Table 4.
Multivariable Cox regression model analysis of time to tuberculosis diagnosis according to treatment status
| Tuberculosis cases per person-years of follow-up* | Incidence per 100 000 person-years (95% CI) | HR (95% CI)† | p value | |
|---|---|---|---|---|
| Treatment | ||||
| Yes | 7/3728 | 187 (89–393) | 0·14 (0·06–0·32) | <0·0001 |
| No | 128/11742 | 1090 (916–1296) | 1·00 | .. |
| Age, years | ||||
| 16–25 | 50/4892 | 1020 (774–1340) | 1·27 (0·88–1·83) | 0·192 |
| 26–35 | 83/10218 | 812 (655–1007) | 1·00 | .. |
| Sex | ||||
| Female | 80/7747 | 1032 (829–1280) | 1·00 | .. |
| Male | 53/7415 | 714 (546–935) | 0·71 (0·50–1·01) | 0·059 |
| ETS region of origin | ||||
| Africa | 21/2323 | 903 (589–1380) | 1·00 | .. |
| The Americas or Europe | 0/68·51 | 0 | 0 | .. |
| East and southeast Asia | 2/258 | 772 (193–3080) | 0·85 (0·17–4·12) | 0·847 |
| South Asia | 52/6845 | 759 (578–996) | 0·87 (0·45–1·66) | 0·655 |
| Tuberculosis incidence in country of origin (cases per 100 000)‡ | ||||
| 40–149 | 9/988 | 910 (473–1750) | 1·00 | .. |
| 150–349 | 61/8157 | 747 (581–961) | 0·73 (0·42–1·26) | 0·257 |
| >350 | 5/351 | 1420 (592–3410) | 0·93 (0·27–3·19) | 0·915 |
| Tuberculosis incidence in area of residence (cases per 100 000)§ | ||||
| ≤9·2 | 8/1176 | 680 (340–1360) | 1·00 | .. |
| 9·3–31·6 | 54/5461 | 988 (757–1290) | 1·72 (0·80–3·69) | 0·163 |
| >31·6 | 53/7373 | 718 (549–940) | 0·66 (0·31–1·43) | 0·300 |
| Deprivation index | ||||
| 1–3 deciles (most deprived) | 80/9246 | 865 (694–1070) | 1·00 | .. |
| 4–6 deciles | 39/4574 | 852 (622–1160) | 1·12 (0·74–1·69) | 0·564 |
| 7–10 deciles (least deprived) | 9/858 | 1040 (545–2010) | 1·14 (0·56–2·34) | 0·708 |
| Year of arrival in England or primary care registration | ||||
| 2011–12 | 12/978 | 1220 (696–2150) | 1·00 | .. |
| 2013–14 | 15/1438 | 1042 (628–1730) | 1·07 (0·54–2·10) | 0·833 |
| 2015–16 | 29/3844 | 754 (524–1080) | 0·90 (0·48–1·68) | 0·744 |
| 2017–18 | 19/3235 | 587 (374–920) | 1·00 (0·46–2·15) | 0·996 |
HR=hazard ratio. ETS=enhanced tuberculosis surveillance system.
*
Included only participants with no missing information for that characteristic.
†
HR (95% CI) and p value estimates were derived from the total cohort of migrants with a positive interferon-γ release assay after multiple imputation for missing values by chained equations model excluding those who developed tuberculosis 21 days after starting treatment (n=6620).
‡
WHO estimated tuberculosis incidence.13
§
UK Health Security Agency estimated tuberculosis incidence in Clinical Commissioning Group area of residence.