The sensitivity and specificity of the mannitol bronchial challenge test to identify asthma in different populations: a systematic review.

OBJECTIVE

Asthma is associated with bronchial hyperresponsiveness, assessed by bronchial provocation tests such as the mannitol test. We aimed to assess the data on sensitivity and specificity of the mannitol test in diagnosing asthma.

DATA SOURCES

We searched electronically the Medline, Embase and Central databases from 1997 to 2019.

STUDY SELECTION

Inclusion criteria were the assessment of the validity of the mannitol test. Risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies tool (QUADAS-2). Data were extracted according to a prespecified list and analysed qualitatively.

RESULTS

A total of 27 studies (4589 individuals, age 6–85 years, cross-sectional [n = 18] and case-controlled [n = 9] study design) were included. Overall sensitivity and specificity ranged from 8% (95% confidence interval [CI] 1–27) to 100% (95% CI 93–100) and 75% (95% CI 67–82) to 100% (95% CI 85–100). Excluding case-controlled design, studies conducted in a clinical setting showed a range from 19% (95% CI 14–27) to 91% (95% CI 59–100) for sensitivity and from 75% (95% CI 67–82) to 100% (95% CI 80–100) for specificity. Heterogeneity was high owing to differences in the populations examined and the methods used.

CONCLUSIONS

Studies on the accuracy of the mannitol test were heterogeneous. Overall specificity was higher than sensitivity and therefore the mannitol test seems to be a suitable diagnostic tool to confirm asthma. However, the high level of heterogeneity among the included studies makes a conclusive statement on the accuracy of the mannitol test difficult and further research is needed. As bronchial provocation tests can be especially useful in patients with an intermediate probability of asthma diagnosis, further studies are needed that include subjects with asthma symptoms but intermediate probability of asthma diagnosis.