TB Manual

In Canadian-born non-Indigenous and foreign-born Canadians, TB incidence rates are highest in those older than 75 years of age.¹⁷⁷ The higher rate of TB in older adults appears to be driven by a combination of higher prevalence of latent infection, increasing frequency of medical co-morbidities and, possibly, waning immunity.¹⁷⁸

TB disease can be more difficult to recognize in older adults.¹⁷⁹ Chest radiographic patterns are often atypical, with older adults less likely to demonstrate cavitation or upper-lobe predominance of infiltrates. Older adults are also more likely to have smear-negative disease.¹⁸⁰

Age over 75 years appears to be associated with poorer TB treatment outcomes, including higher mortality rates and lower completion rates.^180,181 Age over 75 years is also associated with more adverse events, including gastrointestinal upset, rash, drug interactions and drug-induced liver injury.^{144,182–185} A systematic review demonstrated that the odds of drug-induced liver injury in active TB treatment was 30% higher in older people than in younger people.¹⁸⁵ In older patients with active TB, PZA is the most common cause of adverse events. However, these risks should be balanced with the benefit of PZA in people with high bacillary burden.

Recommendation

• We conditionally recommend the routine use of pyrazinamide be avoided in older adults, particularly in those over 75 years of age (poor evidence).

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