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Is the WHO strategy on TB DOTty?

In 1993 the scourge of tuberculosis (TB) led the World Health Organisation (WHO) to declare a global emergency.

In 1993 the scourge of tuberculosis (TB) led the World Health Organization (WHO) to declare a global emergency. Two decades later TB remains a public health problem. In 2012 there were 8751 cases reported in the UK, and between 2000 and 2012, the number of multi-drug resistant TB cases in the UK rose from 28 per year to 81 per year.

A cornerstone of TB treatment and control has been directly observed treatment (DOT), and although the WHO reports that the strategy has 'successfully treated' many patients using DOT, the evidence for its usefulness is equivocal. For example, in 2009 a Cochrane Review reported that 'DOT did not improve cure rates compared with people without DOT', and guidelines from NICE published in 2011 found 'no evidence from controlled studies on the use of DOT in the UK'.

It appears that improvements in the UK depend on establishing a ratio of 40 TB notifications or fewer to one TB nurse, a target which current guidelines do not yet specify. In any case, a UK shortage of clinical nurse TB specialists would jeopardise the effective implementation of a DOT strategy.

In the UK, around 72% of TB patients come from ethnic minority backgrounds, and TB rates among the homeless, alcoholics and the mentally ill are many times that of the rest of the UK population. Current opinion is that DOT may improve compliance among these populations, and there is a moral argument that society as a whole would benefit if DOT was mandatory among sometimes non-compliant groups.

It might make sense at one level but there are ethical dimensions to be considered. DOT may challenge the status of patient autonomy, and may draw attention to the fact that an individual has TB, raising issues of confidentiality. There have been cases in developed and developing countries of healthcare workers enforcing DOT strategies by threatening and coercing patients.

As always, human behaviour will exert a decisive influence on the success or failure of any TB control strategy.

George Winter, medical writer