RetourTB in older people is particularly relevant in countries with low incidence of TB in the WHO regions of the Americas and Europe, and is a growing problem in Asia because of the increasingly ageing population (5, 74). Outbreaks in nursing homes are frequently described, particularly in countries with a low incidence of TB (75, 76). The occurrence of TB among older people is also related to the higher prevalence of comorbidities (e.g. diabetes, chronic renal impairment and smoking) in this age group. The disability-adjusted life-years lost due to TB in patients aged over 65 years range from 8.2% in Europe to 18.7% in East and Central Asia (77).
The main challenges to successful treatment among older patients include poor drug tolerance, adverse events and poor treatment adherence, all of which could potentially lead to unfavourable treatment outcomes.
Recent data from Japan on TB patients notified in 2017 indicate that the case-fatality rate increased with age, being 3.1% for those aged 0–64 years, 15.3% for those aged 65–74 years, 27.0% for those aged 75–84 years and finally 47.4% for those aged 85 years and over (43, 74). A study in Nigeria described lower sputum smear conversion after the intensive phase of treatment in patients aged over 60 years, although only extrapulmonary TB and HIV coinfection were significant predictors of a poorer outcomes (72).
Gastrointestinal upset and hepatitis are reported as the most frequent adverse events in older people (78, 79). In Japan, in patients aged 80 years or more treated for DS-TB with the 6-month regimen, the prevalence of hepatitis was higher among those receiving treatment with isoniazid, rifampicin, pyrazinamide, and ethambutol than among those receiving isoniazid, rifampicin, and ethambutol, although treatment outcomes were similar in the two groups (80).
Clinical attention should be paid to older patients undergoing pyrazinamide treatment, to rapidly identify and manage any adverse events that eventually appear. Guidelines from the American Thoracic Society consider the option of excluding pyrazinamide in patients aged over 80 years (43).
Ethambutol is excreted by the kidney. A low glomerular filtration rate (GFR) (i.e. <30 mL/minute−1) has a poor prognosis in the treatment of TB (81). In older people, the dose should be reduced according to the estimated GFR, but the time between doses should also be increased, to ensure that high blood levels of the drug do not persist (82).
Older individuals are likely to have several comorbidities and are therefore likely to be taking other medicines; hence, there is potential for drug–drug interactions (83). The interaction between the anticoagulant warfarin and rifampicin is especially problematic, and either heparin or a non-vitamin K oral anticoagulant are considerably safer. Other important interactions include those with statins, analgesics (e.g. celecoxib and losartan), oral antidiabetic medications, steroids, calcium channel blockers and theophyllines. When prescribing TB treatment in older people, it is always important to evaluate potential interactions among the different drugs prescribed to manage comorbidities (72).
Among older people, particular care is also necessary to ensure correct adherence to the prescribed treatment within a multidisciplinary and patient-centred approach (43, 84).
Implementation considerations
- Although the drugs used to treat DS-TB are generally well tolerated and are unlikely to cause adverse events among older people, monitoring of adverse events is important to ensure rapid notification and prompt management.
- notification and prompt management. • Management of older people with TB involves a multidisciplinary approach, in view of the additional treatments that are often required to manage comorbidities and the potential need to adjust drug dosing. A TB consilium to support the management of people with TB that is difficult to treat may be of help (62).
- Supporting adherence, taking into account age-related physical and psychological disabilities, is an important management component when treating DS-TB in older people. Thus, collaboration with partners in the community, including family members, carers, health care workers and welfare workers, is essential.
- Coordination of NTPs with geriatric services may be relevant in countries where TB in older people is increasingly notified.