Two studies were included that assessed the direct health impact of NAAT (Theron et al. 2014; Yoon et al. 2012). Both studies were conducted in a high prevalence setting and applicability to the Australian healthcare system is therefore questionable. A high-quality RCT reported no difference in morbidity outcomes at 2 and 6 months follow-up when NAAT and AFB microscopy were compared. However, a strong trend indicating fewer deaths in the NAAT group compared with the AFB microscopy group was observed at 2 months, but this trend was no longer apparent at 6 months. A historical control study of medium quality found no difference in the mortality rate at 2 months follow-up when comparing NAAT with no NAAT.
The authors of both studies suggested that high rates of treatment initiation based on empiric evidence in the no-NAAT groups probably underestimated the morbidity and/or mortality rate in the NAAT groups. Yoon et al. (2012) also suggested that sicker patients in the NAAT compared with the no-NAAT group contributed to this underestimation in their study.
