Delay in diagnosis of tuberculosis: of remaining concern in England and Wales.

Abstract

Delays in the diagnosis of tuberculosis (TB) are relatively common, and have an impact at both the individual level by increasing the risk of morbidity and mortality, and at the community level by increasing the risk of transmission. Central to tuberculosis control is early case finding and initiation of treatment, especially for smear positive pulmonary TB cases. TB has declined as a health problem in England and Wales, with 5608 cases in 1995. As a disease becomes rarer, there is a loss of skills in its management. A UK medical student may nowadays qualify without ever seeing a patient with active TB. This lack of ‘exposure’ to TB could lead onto diagnostic delays in a low prevalence country such as the UK, with attending doctors forgetting the possibility of TB as a diagnosis. Medical delays, mainly a delay in referral, can be as important as patient delay. In 43 pulmonary TB cases, treated at Blackburn Royal Infirmary during 1991–1996, overall median delay from onset of symptoms to diagnosis was 7 weeks (interquartile range 4–13), with no difference between White (W) (7 (4.5–12.5)) and South Asian (SA) (8 (4–19)) ethnic groups (MW U-test p-value 0.96) (Fig. 1). If an ‘acceptable’ period between onset of symptoms and diagnosis is defined as 30 days, then 72 per cent of the smear positive cases (W 12/16 (75 per cent), SA 9/13 (69.2 per cent)) fell outside of this ‘acceptable’ period. Whereas 12 White cases had recognized pre-existing medical (e.g. alcoholism, diabetes, intravenous drug use) or social risk factors (e.g. living in homeless hostel) for TB, just one South Asian case had a preexisting medical risk factor (diabetes). The median ages of the two groups (W 22, SA 21) were also significantly different (W 62, SA 34 years, p-value <0.002). Although the delay in Blackburn was similar to that found in other studies, it is of considerable concern that 72 per cent of smear positive cases experienced delays of more than 1 month from onset of symptoms to diagnosis. Overall delay comprises both patient’s delay in presentation to the health services and doctor’s delay in referral and/or diagnosis. Unfortunately, the time lapse from presentation at a health care facility to hospital referral was often not available, making it impossible to ascertain these delays separately. This is not an uncommon situation. The importance of patient awareness and clinical suspicion of TB on the part of the attending doctor cannot be stressed enough. Awareness levels need to be raised in both the general community and the medical profession, especially with the potential lack of contact with active TB cases during presentday medical training in the UK. Although the two ethnic groups delays’ were similar, the age differences and the presence or absence of pre-existing social or medical risk factors require that the methods of awareness raising amongst these two groups will have to reflect their differing situations. There is also a need for further research to identify the reasons for the delay between onset of symptoms in TB patients and diagnosis, as reduction in such delays is an important public health priority that needs to be addressed in such low prevalence countries as the UK.