TB treatment outcomes in England, 2021
Updated 3 August 2023
Applies to England
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About this report
Report series
The aim of this report is to describe the diagnosis and microbiological testing of tuberculosis (TB) in England up to the end of 2021. It is the fifth in a series of 7 reports which have previously been published as a single report titled TB in England. This is the first year that they have been published as a series of smaller reports and each will describe different aspects of TB incidence, treatment, and prevention in England.
Related reports
- TB incidence and epidemiology in England, 2021
- TB diagnosis, microbiology and drug resistance in England, 2021
- TB in children: Incidence, epidemiology and microbiology in England, 2021
- TB treatment in England, 2021
- TB treatment outcomes in England, 2021
- TB prevention in England, 2021
- TB in children: Treatment and prevention in England, 2021
Report format
Information on how this series of reports fits within the TB Action Plan for England 2021 to 2026 (jointly published with National Health Service (NHS) England) along with a list of key monitoring indicators for the report series can be found in TB incidence and epidemiology in England, 2021.
Intended audience
This report is primarily aimed at healthcare professionals involved in the management of people with TB, healthcare commissioners involved in the planning and financing of TB services, public health professionals, researchers, and governmental and non-governmental organisations involved in TB control.
Main messages
TB is curable and collecting and reporting data on treatment outcomes is important to assess success of treatment, which is essential in preventing the onwards transmission of TB.
In 2021:
- the proportion of people with non-severe TB, not identified as multi-drug resistant (MDR) or rifampicin resistant (RR) TB (non-MDR or non-RR TB) who successfully completed TB treatment remains stable but lower than the action plan target (84% compared with 90%)
- people with a social risk factor such as homelessness continue to have significantly lower TB treatment success rates than people without (77% compared with 84%) with no improvements over the 6-year comparison period close to the 5% action plan target for this group
- people with the following characteristics were less likely to complete non-MDR or non-RR TB treatment successfully: males, older people, people with a social risk factor, history of imprisonment, people with a repeat episode of TB and those with severe TB disease requiring a longer treatment duration
- TB mortality rates for those treated for non-MDR or non-RR TB were the highest recorded over the last 10 years; 5.2% in those with non-severe TB, 6% in the entire non-MDR or non-RR cohort and 12.8% in those with severe TB, significantly higher than the previous low for people notified pre-pandemic in 2019
- the proportion of people lost to follow up did not increase in 2021, indicating that people who were diagnosed in the peak pandemic year of 2020 continued to engage with and receive TB treatment services
- the proportion of people treated for MDR or RR TB who successfully completed treatment within 24 months has increased over the last 10 years, but slightly decreased compared with the previous year (70.6% compared with 73.1%)
Please note that all treatment outcome results in this report are not directly comparable with earlier reports due to people diagnosed with TB post-mortem not being excluded from treatment outcome analyses in previous reports.
TB treatment outcomes in the non-MDR or non-RR TB cohort (without central nervous system disease)
Treatment outcomes at 12 months and last recorded treatment outcome
Treatment outcomes are reported according to the year of notification. For people treated for non-MDR or non-RR TB, outcomes are reported for those notified up to and including 2020 as that is the latest year of notifications for whom treatment completion is expected within the 2021 data. For people treated for MDR or RR TB, outcomes are reported for those notified up to and including 2019. For further definitions of TB treatment cohorts please see the Methodology and definitions section.
Mutually exclusive treatment outcome categories are shown in Table 1 below. For cases of non MDR or non-RR TB notified in 2020, by 12 months since notification:
- 84.2% had completed treatment
- 5.2% had died
- 3.0% were lost to follow up
- 4.0% were still on treatment
- 1.3% had stopped treatment
Overall treatment completion increased to 87.6% for last recorded treatment outcome. 12-month TB treatment outcomes for this cohort from 2011 to 2020 are shown in Table 1 of the TB treatment outcomes in England dataset.
Of those notified in 2020 and reported to still be on treatment at 12 months (141 people, Table 1) 115 (81.6%) subsequently completed treatment as their last recorded outcome. At the time of data close, 23 were still on treatment, 1 was lost to follow-up and 2 people had their treatment stopped. Of those notified in 2020 and reported as not evaluated at 12 months, 3 were subsequently reported as lost to follow-up and the rest remained as non-evaluated. Last recorded treatment outcomes for this cohort from 2011 to 2020 are shown in Table 2 of the TB treatment outcomes in England dataset.
Table 1. Treatment outcome at 12 months and last recorded outcome for people notified in 2020 with non-MDR or non-RR TB with expected treatment duration less than 12 months, England, 2020
| TB treatment outcome at 12 months (n) | TB treatment outcome at 12 months (%) | Last recorded treatment outcome (n) | Last recorded treatment outcome (%) | |
|---|---|---|---|---|
| Treatment completed | 3,003 | 84.2 | 3123 | 87.6 |
| Died | 184 | 5.2 | 184 | 5.2 |
| Lost to follow-up | 106 | 3.0 | 110 | 3.1 |
| Still on treatment | 141 | 4.0 | 23 | 0.6 |
| Stopped | 47 | 1.3 | 44 | 1.2 |
| Not evaluated | 85 | 2.4 | 82 | 2.3 |
| Total | 3,566 | 100 | 3,566 | 100 |
Note: Not evaluated includes unknown outcome and transferred out.
Action Plan indicators 15 and 16: Proportion of treatment completion within 12 months in the non-MDR or non-RR TB cohort with and without a social risk factor
Indicators 15 and 16 relate to all individuals with non-severe TB treated with a first-line drug regimen for non-MDR or non-RR TB to complete treatment within 12 months of starting.
The target for indicator 15 is a 5% annual increase in in treatment completion within 12 months for people with one or more social risk factors from a baseline average from people notified in 2020 and 2021 of 77.8%. The largest percentage increase observed over the last 6 years was 3% between 2018 and 2019. The target for indicator 16 is 90% completion of treatment within 12 months in all people in the cohort, to be achieved by 2026.
Figure 1. Proportion of people treated for non-MDR or non-RR TB without central nervous system (CNS) disease and with 1 or more social risk factors who completed treatment within 12 months
In 2021, 76.8% of people notified in 2020 with one or more social risk factors completed treatment within 12 months. This proportion has not significantly changed over the last 6 years (Figure 1). The baseline average for future comparisons of treatment completion within 12 months is 77.8% (people notified in 2019 and 2020). The proportion of those completing treatment within 12 months in this population is significantly lower in those with a social risk factor compared with those without (76.8% compared with 85.3%, p-value less than 0.001).
Figure 2. Proportion of people with non-severe TB treated for non-MDR or non-RR TB who completed treatment within 12 months compared with the target of 90%
In 2021, 84.2% of people notified in 2020 with non-severe TB treated with first line drug for non-MDR or non-RR TB completed treatment by 12 months. This is the lowest percentage seen in the last 6 years, but with no significant difference over time. Analysis of factors associated with treatment outcomes are presented in subsequent sections. Compared with an average of 85.7% over the last 3 years, to reach the target of 90% treatment completion by 2026 will require an average annual increase of 1.1%. Improvements of this magnitude have been observed in only 3 non-contiguous yearly comparisons over the last 11 years. When observed over the longer term, treatment completion has not changed since around 2007, varying between 82% and 88%, from a low of 65% in 2001 (Table 1 of the TB treatment outcomes in England dataset).
Treatment outcomes at 12 months over time are shown in Figure 3a and 3b and in Table 1 of the TB treatment outcomes in England dataset. The proportion of those not evaluated for the 2020 cohort is expected to decrease slightly as more missing values are entered over time. The proportion of those who died within 12 months (measured from start of treatment, diagnosis or notification depending on which is the latest data point available) was 5.2%, the highest recorded in recent years and significantly higher than 2019 (p-value 0.004) (Figure 3b). In this cohort there were no further deaths reported in the last recorded outcome (Table 1). However, as the follow-up period for this group is shorter than earlier cohorts, there is the potential that further deaths could occur in those who are currently not evaluated or lost to follow-up. It has yet to be determined if this increase is reflective of the overall increased mortality occurring from the COVID-19 pandemic. The proportion of persons lost to follow-up did not increase, indicating that people who were diagnosed in the peak pandemic year of 2020 continued to engage with and receive TB treatment services.
Figure 3a. Treatment outcome at 12 months for people with non-MDR or non-RR TB with expected treatment duration less than 12 months, England, 2011 to 2020
Figure 3b. Breakdown of people evaluated who did not complete treatment at 12 months for people with non-MDR or non-RR TB and expected treatment duration less than 12 months, England, 2011 to 2020
12-month treatment outcomes by age, sex and region
Treatment outcomes at 12 months are reported for the cohort of people treated for non-MDR or non-RR TB and without severe disease in the TB treatment outcomes in England dataset. They are reported:
- by age group from 2011 to 2020 in Table 3 of the dataset
- by age and sex for notifications in 2020 in Table 4 of the dataset
- by UKHSA centre for notifications in 2020 in Table 5 of the dataset
- by proportions of treatment completion by UKHSA centre from 2011 to 2020 in Table 6 of the dataset
Please see the section Factors affecting treatment completion at last recorded outcome in the entire non-MDR or non-RR cohort for quantification of the associations of age, sex and region with treatment completion as the last recorded outcome for people notified in 2020.
Action plan indicator 17: Proportion of people who had died at their last treatment outcome (non-MDR or non-RR TB cohort)
There is no specific target for this indicator in people who are expected to complete treatment within 12 months of starting treatment with non-severe TB treated with first-line drug regimen for non-MDR or non-RR TB.
As shown in Figure 4, the proportion of people who had died as their last reported treatment outcome in the 2019 notification cohort (pre-pandemic) was 3.9% compared with 5.2% in the 2020 notification cohort, but this difference did not quite reach statistical significance.
Figure 4. Proportion of people with non-MDR or non-RR TB who died at their last recorded treatment outcome and had an expected treatment duration of less than 12 months, England, 2015 to 2020
Treatment duration
Of those notified in 2020 who were expected to complete treatment within 12 months and had a recorded treatment end date (3,091), most completed within the standard 6 to 8 months (66.4%). Just under 6% completed in less than 6 months, shorter than the full duration of the standard course, which may occur if persons start treatment abroad. Since 2011, the proportion of people who take longer to compete their treatment from 8 to 10 or 10 to 12 months has tended to increase (Table 7 of the TB treatment outcomes in England dataset) to 15.4% and 8.4% for those notified in 2020.
TB treatment outcomes for the non-MDR or non-RR TB cohort with CNS disease
Last recorded treatment outcomes in this cohort for those notified in 2020 are shown in Table 2 and from 2011 to 2020 in Table 8 of the TB treatment outcomes in England dataset. At the last recorded outcome, 77.0% of people notified in 2020 had completed treatment, whilst 2.0% were still on treatment. Due to a shorter follow-up period for cases notified in 2020, the proportion of people that complete treatment is expected to increase, as in previous years. For people notified in 2019, 83.2% (387 out 465) had completed treatment at the last recorded outcome.
Table 2. Last recorded TB outcome for people notified in 2020 with non-MDR or non-RR TB cohort with CNS disease, England, 2020
| TB outcome | n | % |
|---|---|---|
| Completed | 348 | 77.0 |
| Died | 58 | 12.8 |
| Lost to follow-up | 15 | 3.3 |
| Still on treatment | 9 | 2.0 |
| Stopped | 3 | 0.7 |
| Not evaluated | 19 | 4.2 |
| Total | 452 | 100.0 |
Note: Not evaluated includes unknown and transferred out.
Last recorded TB treatment outcomes for the entire non-MDR or non-RR TB cohort
Last recorded treatment outcome for the entire non-MDR or non-RR TB cohort are shown in the TB treatment outcomes in England dataset:
- by year (2011 to 2020) in Table 9
- by site of disease in Table 10
- by UKHSA region in Table 11
Treatment completion as the last recorded outcome for the entire non-MDR or non-RR TB cohort has not notably changed over time, with a peak of 90.2% in 2013 and a 10-year average of 88.9%. The proportion of people who had died at their last reported outcome was 6.0% for those notified in 2020, more than the previous high of 5.3% for people notified in 2015.
For people notified in 2020, the proportion of people who had died was greater in those who were notified with pulmonary disease, both with other sites of disease (1,747 completed treatment; 8.5% died) or without (1,185 completed treatment; 7.8% died), compared with people notified with extrapulmonary disease only (1,724 completed treatment; 3.3% died). People notified with TB meningitis and miliary disease had the highest proportions of deaths (66 completed treatment, 21.2% died; 101 completed treatment, 20% died) compared with extra-thoracic lymph node TB (827 completed treatment, 1.4% died).
Variations in treatment outcomes were generally small, but the proportions of people who were lost to follow up were highest in Yorkshire and the Humber at 5.1% where treatment completion was also one of the lowest at 78.9%. Whilst the North East had the lowest treatment completion (78.0%) with the greatest number who died (12 people 14.6%).
All deaths for the entire non-MDR or non-RR TB cohort
For people notified in 2020 in the non-MDR or non-RR TB cohort there were an additional 30 deaths in people who were diagnosed with TB post-mortem and are not included in the treatment outcome figures above. When these people are included, the proportion of all people notified with TB that died increased to 6.7% out of 4,048 people.
Cause of death in the entire non-MDR or non-RR TB cohort
Out of 242 deaths of people in this cohort notified in 2020, TB was reported to have caused or contributed to death for 43.8%, was incidental to death for 21.9% and was unknown or missing for the remaining 34.3%. For the 30 deaths that were in people diagnosed post-mortem, it was unknown for all if TB was the cause of death.
Characteristics of people who died in the entire non-MDR or non-RR TB cohort
People who died (excluding those that were diagnosed post-mortem) were older, more likely to be male, more likely to be born in the UK and more likely to have pulmonary disease compared with non-pulmonary disease. Specifically:
- 59.5% of those that died were aged 65 years or more, compared with 11.1% of people in that group who did not
- 69.8% of those that died were male compared with 57.7% of people in that group who did not
- 38.7% of those that died were born in the UK compared with 26.1% of people in that group who did not
- 73.6% of those that died had pulmonary disease compared with 50.6% of people in that group who did not
All of these figures have a p-value less than 0.001.
Out of 242 people who died, 211 (87.2%) had a known treatment start date, of whom, 59.2% were reported to have died within 2 months of starting treatment. However, treatment delay was significantly shorter in those that died compared with those that did not (median 64 days from symptom onset to start of treatment in 192 who died with recorded information, compared with a median of 95 days in those who did not die, p-value less than 0.001), suggesting that treatment delay was not a main reason for most of these deaths.
Factors affecting treatment completion at last recorded outcome in the entire non-MDR or non-RR cohort
Table 3. Factors associated with treatment completion as the last recorded outcome for people notified in 2020 with non-MDR or non-RR TB
| Level of factor | % treatment completed | Risk ratio | 95% CI |
|---|---|---|---|
| Female | 88.6 | Reference | NA |
| Male | 84.8 | 0.96 | 0.94 to 0.98 |
| Age group 0 to 14 years | 90.5 | 1.00 | 0.95 to 1.05 |
| Age group 15 to 44 years | 90.6 | Reference | NA |
| Age group 45 to 64 years | 87.6 | 0.97 | 0.94 to 0.99 |
| Age group 65 years or more | 66.4 | 0.73 | 0.69 to 0.78 |
| Non-pulmonary disease | 89.3 | Reference | NA |
| Pulmonary disease | 83.7 | 0.94 | 0.91 to 0.96 |
| Born outside of the UK | 87.6 | Reference | NA |
| Born in the UK | 85.1 | 0.97 | 0.94 to 1.00 |
| No social risk factor | 87.4 | Reference | NA |
| One or more social risk factors | 79.9 | 0.91 | 0.88 to 0.96 |
| No history of incarceration | 88.5 | Reference | NA |
| History of incarceration | 79.7 | 0.90 | 0.83 to 0.98 |
| New TB diagnosis | 87.8 | Reference | NA |
| Previous history of TB diagnosis | 81.5 | 0.93 | 0.87 to 0.99 |
| Treatment delay 0 to 2 months | 85.3 | Reference | NA |
| Treatment delay 2 to 4 months | 86.5 | 1.01 | 0.98 to 1.05 |
| Treatment delay more than 4 months | 90.0 | 1.05 | 1.02 to 1.09 |
| Non-severe (CNS) TB | 87.6 | Reference | NA |
| Severe (CNS) TB | 77.0 | 0.88 | 0.83 to 0.93 |
Note: Total number included in the analysis is 4,018. Data is missing for 7,9%, 3.4% and 10.3% for analyses of prison history, previous TB diagnosis and treatment delay.
As shown in Table 3, there were significant differences in the proportion of people who completed TB treatment by socio demographic and disease characteristics. Notably people with a history of imprisonment had a high decreased probability of completing TB treatment (minus 10%) compared with a 12% decreased probability for people diagnosed with severe TB disease involving CNS. People aged more than 65 years had the greatest probability of not completing treatment and of death, but the excess mortality compared with people of the same age and background has not been assessed here. The probability of completing treatment was significantly lower in 2 regions compared with London, the North East (risk ratio: 0.89, 95% confidence interval (CI) 0.79 to 0.99) and Yorkshire and the Humber (risk ratio: 0.89, 95% CI 0.84 to 0.95), 2 areas with lower rates of TB notification incidence and potentially fewer specialised resources to provide patient support.
TB treatment outcomes in the drug resistant (MDR or RR TB) cohort
TB outcomes for the MDR or RR cohort are reported at 24 months, so the most recent complete data is for people notified in 2019. The 2019 cohort comprised 68 people treated for MDR or RR TB. Fifty-two of these were culture confirmed MDR or RR TB at diagnosis, of whom 8 had pre-extensively drug resistant (pre-XDR) TB and none had XDR TB (see Table 8 TB Diagnosis, microbiology and drug resistance in England dataset).
Treatment outcome at 24 months and last recorded outcome for persons treated for drug-resistant TB notified in 2019 are shown in Table 4 and for notification years 2011 to 2019 in Figure 5 and Tables 12 and Table 13 in the TB treatment outcomes in England dataset. Forty-eight people notified in 2019 completed treatment within 24 months. Five people completed treatment after 24 months, bringing overall treatment completion for people notified in 2019 to 77.9%. Although overall treatment completion for people with MDR or RR TB has remained similar from 2010 to 2019, there has been a gradual increase in treatment completion within 24 months, ranging from 43.9% in 2010 to 73.1% in 2018 as shown in Figure 5 and Table 12 in the TB treatment outcomes in England dataset.
Figure 5. Proportions of people treated for drug resistant TB (RR or MDR TB) with treatment completion at 24 months or last recorded outcome, England, 2011 to 2019
Table 4. 24-month and last recorded treatment outcomes for the MDR or RR TB cohort, England, 2019
| TB treatment outcome at 24 months (n) | TB treatment outcome at 24 months (%) | Last recorded treatment outcome (n) | Last recorded treatment outcome (%) | |
|---|---|---|---|---|
| Treatment completed | 48 | 70.6 | 53 | 77.9 |
| Died | 6 | 8.8 | 6 | 8.8 |
| Lost to follow-up | 5 | 7.4 | 5 | 7.4 |
| Still on treatment | 5 | 7.4 | 1 | 1.5 |
| Stopped | 1 | 1.5 | 1 | 1.5 |
| Not evaluated | 3 | 4.4 | 2 | 2.9 |
| Total | 68 | 100.0 | 68 | 100.0 |
Note: Not evaluated includes unknown and transferred out
For people with known treatment start and completion dates, 34.0% (18 out of 53) had less than 18 months of treatment, of which 8 had less than 12 months of treatment (Table 14 in the TB treatment outcomes in England dataset). At the last recorded outcome, 1.5% of the 2019 RR or MDR TB cohort were still on treatment, which was comparable to 2018 (1.9%).
In 2019, 8.8% (6 out of 68) people had died at their last recorded outcome, compared with 3.8% (2) from the MDR or RR cohort notified in 2018 (Table 4 and Table 13 in the TB treatment outcomes in England dataset). The deaths occurred among people aged 35 to 83 years old, with 4 of the deaths among people aged over 50 years old and 3 of which were not born in the UK.
TB contributed to the death of 2, was incidental to 3 and had an unknown relationship to the remaining death.
Five (7.4%) people from the MDR or RR TB cohort notified in 2019 were lost to follow-up; all were born outside the UK with 4 confirmed being lost to follow-up abroad. From 2001 to 2019 only 3.2% (5 people out of 157) from the MDR/RR cohort who were lost to follow up were born in the UK.
The proportion of those not evaluated from the 2019 cohort is expected to decrease slightly as currently missing values will be recorded over time. Treatment outcomes at 24 months for people with MDR or RR TB from 2010 to 2019 are shown in Figure 6a and 6b below and in Table 12 of the TB treatment outcomes in England dataset. From 2010 to 2019 there has generally been a lower proportion of people with MDR or RR TB who were lost to follow up, still on treatment, or who stopped treatment by 24 months, potentially indicating how improved patient management and TB surveillance have improved treatment adherence over the last 10 years.
Figure 6a. Treatment outcome at 24 months for people with MDR or RR TB with expected treatment duration less than 24 months, England, 2010 to 2019
Figure 6b. Breakdown of people evaluated who did not complete treatment at 24 months for people with MDR or RR TB and expected treatment duration less than 24 months, England, 2010 to 2019
Discussion and conclusions
Treatment completion rates in people treated for non-MDR or non-RR TB have not increased over the current comparison period of 10 years. History of imprisonment was strongly associated with a decreased probability of treatment completion indicating that more support is needed for this at-risk group. More detailed and complete data on when and where people with TB were imprisoned, not available within national TB surveillance system (NTBS) is required to conduct more in-depth analysis to better understand how services can be best improved in this at-risk population.
All of the observed treatment outcomes of death in the non-MDR or non-RR TB cohort were the highest observed over the last 10 years, with some reaching statistical significance compared with 2019. However, loss to follow up was not increased indicating that people who were diagnosed in the peak pandemic year of 2020 continued to engage with and receive TB treatment services. Shorter treatment delay was associated with a decreased probability of treatment completion and was more common in those that died. This combined with the high proportion of deaths that occurred within the first 2 months of starting treatment (59.2%) might suggest that a high proportion of deaths occurred in those with a more acute presentation of disease, resulting in shorter treatment delays but an increased risk of dying. This hypothesis needs further investigation requiring data outside of routine TB surveillance data.
It has yet to be determined if the increase in mortality in people notified in 2020 is reflective of the overall increased mortality occurring during the pandemic or if people with TB were at particular increased risk of COVID-19 related mortality. There was no evidence from available data regarding the role of TB in the cause of death to suggest that TB considered to be causal or to have contributed to death either increased or decreased for those who were notified in 2020 compared with previous years. Further research is required to investigate the effect of the pandemic on TB outcomes and is included as part of priority 1 of the joint UKHSA and NHS England TB Action Plan.
There have been no consistent changes in treatment outcomes for people treated for MDR or RR TB over the 10-year comparison period. However, treatment completion at last recorded outcome was the highest recorded for those notified in 2018 compared with the second highest recorded for the current reporting year, which will likely increase further with further follow-up. This may indicate the beginning of a trend for increased treatment completion in this cohort, possibly attributable to the effect of the introduction of improved second line treatment regimens with fewer injectables and expected side-effects and will be monitored and investigated in further reports.
Recommendations
Recommendation 1
Causes of death in patients diagnosed with TB should be discussed in cohort review, focussing on opportunities to reduce TB morality.
Recommendation 2
NHS TB services should review causes of non-TB treatment completion as part of cohort review and at a service level. Interventions to improve TB treatment completion rates should be encouraged.
Recommendation 3
Patients with TB and social risk factors should be offered support to help the complete treatment. The impact of support given should be kept under review.
How these recommendations support the action plan priorities
These recommendations will support the following action plan priorities.
3.5: Focus on improving the detection and management of TB in people with social risk factors with the support of the Tackling TB in Under-Served Populations (USP)’ Resource.
4.1.1: All partners in TB diagnosis, treatment and patient-centred care in high and low incidence areas work to the national TB service specification including:
- TB services and commissioners achieve and maintain 85% treatment completion rates and work to achieve 90% treatment completion rates by 2026
- provision of both doctor and nurse led clinics
- a consistent approach to enhanced case management (ECM)
- an integrated approach to multi-disease prevention for those with social risk factors and others with TB, blood borne viruses (BBVs) and other conditions
Methodology and definitions
General methodology for TB notifications, data production, cleaning and reporting are described in the methodology and definitions section of TB incidence and epidemiology in England, 2021.
TB cohort definitions
For the purposes of reporting treatment outcomes for people with TB, 2 mutually exclusive cohorts are defined. They are:
- people with TB who were treated with a second line drug regimen for MDR or RR TB
- those who were not identified as MDR or RR TB and were treated with a first line treatment regimen for non-MDR or non-RR TB
Under this definition, people with TB resistance to isoniazid, ethambutol and/or pyrazinamide but without resistance to rifampicin are included in the non-MDR or non-RR TB cohort. Please see TB diagnosis, microbiology and drug resistance in England, 2021 for further details of the detection and classification of drug resistance.
Outcomes are reported for the non-RR and non-MDR cohort according to the year of notification up to, and including, 2020. This is to ensure that at least one year of data is available to report treatment outcome by the expected standard treatment duration of less than 12 months. In this cohort, outcomes are reported separately for persons with CNS disease, or in those in whom CNS disease cannot be excluded, which includes those with spinal, cryptic disseminated or miliary disease. For this sub-group, the last recorded treatment outcome is reported as standard treatment is a minimum of 12 months.
Outcomes are reported for the MDR or RR TB cohort according to the year of notification, up to, and including, 2019. This is to ensure availability of data for the expected standard treatment duration of up to 24 months.
TB treatment outcomes were extracted from NTBS (2020 to 2021) and Enhanced TB Surveillance system (ETS) (2001 to 2020) and cleaned and validated using comment fields, post-mortem diagnoses, date of key events and case-manager follow-up. TB diagnoses that were recorded at post-mortem were excluded from TB treatment outcomes as these cases were not treated. These deaths are reported separately and added to TB treatment deaths to report total TB deaths. This is a change from methodology in previous reports. Therefore, please note that all treatment outcome results in this report are not directly comparable with earlier reports.
Geography
UKHSA centre was derived from UKHSA region of residence based on individual’s residential postcode. If missing, UKHSA centre in which treatment occurred was used, for example if a person had no fixed abode.
Data presented by UKHSA centres is presented in order of most individuals with TB in 2021.
Cleaned postcodes were assigned boundary layers and merged with boundaries for clinical commissioning groups, integrated care boards, Upper Tier Local Authorities and local authorities sourced from the Central Lookups Database within the UKHSA Data Lake which is managed by the Public Health Data Science team. These are available in the UKHSA layers of the map software (GIS).
Statistical methods
Confidence intervals
95% CI are model derived and were calculated using assumptions of the binomial distribution for proportions.
Comparisons of proportions
Chi squared tests were used to compare proportions. P values less than 0.05 are reported as “statistically significant”.
Risk ratios
Risk ratios are model derived using the binomial distribution for proportions.
Software packages
All statistical analysis was carried out using Stata 17.0. ArcGIS 10.5 was used to produce all maps shown in the report.
Glossary
Post-mortem diagnosis
A person diagnosed at post-mortem is defined as having TB which was not suspected before death, but a TB diagnosis was made at post-mortem, with pathological and/or microbiological findings consistent with active TB that would have warranted anti-TB treatment if discovered before death.
Pulmonary TB
A person with pulmonary TB is defined as having TB involving the lungs and/or tracheobronchial tree, with or without extra-pulmonary TB diagnosis. In this report, in line with the World Health Organization’s recommendation and international reporting definitions, miliary TB is classified as pulmonary TB due to the presence of lesions in the lungs, and laryngeal TB is also classified as pulmonary TB.
Social risk factor
Social risk factors for TB include current alcohol misuse, current or history of homelessness, current or history of imprisonment, current or history of drug misuse, current mental health needs, or current status as an asylum seeker or detainee in an immigration removal centre. Please see the reporting methodology in TB incidence and epidemiology in England for further details of these variables.
Risk ratios
Risk ratios quantify the relative risk of the outcome we are interested in between 2 different groups. For example, the relative risk of pulmonary disease in males compared with females. This is calculated as the proportion of males with pulmonary disease divided by the proportion of females with pulmonary disease, which is a risk ratio of 1.18 (95% CI 1.11 to 1.25). This is interpreted that males have an 18% increased risk of pulmonary disease compared with females and we have 95% confidence that the true increased risk lies within the range of 11% to 25%.
If a 95% CI for a risk ratio includes the value of 1.0 then we cannot infer that the true risk ratio is different from 1. Thus, we would say that these results are not providing any evidence that the observed magnitude of the risk ratio is ‘statistically important’.
If a risk ratio of less than 1.0 is reported, such as risk ratio 0.85, this is interpreted that the group of interest have a 15% reduced risk of the outcome.
95% Confidence Interval
In this report, model derived 95% CI are often presented alongside percentages and relative risks. For example, the percentage of TB notifications with pulmonary disease is 52.7% (95% CI 51.3% to 54.2%). This can be loosely interpreted as that we have 95% confidence that the true but unknown value of this percentage in the population lies within the range of 51.3% to 54.2%.
The UK Health Security Agency (UKHSA)
UKHSA was launched on 1 October 2021. It is an executive agency of the Department of Health and Social Care. UKHSA is responsible for planning, preventing and responding to external health threats, and providing intellectual, scientific and operational leadership at national and local level as well as with partners in other countries. Most health protection functions are devolved to the other UK nations’ public health teams in the UK, so this report only covers TB notifications and data from England.