This study aimed to analyze the accuracy of two methods for detecting halitosis, the organoleptic assessment by a trained professional (OA) with volatile sulfur compounds (VSC) measurement via Halimeter ® (Interscan Corporation) and information obtained from a close person (ICP). Methodolody Participants were patients and companions who visited a university hospital over one year period to perform digestive endoscopy. A total of 138 participants were included in the VSC test, whose 115 were also included in the ICP test. ROC curves were constructed to establish the best VSC cut-off points. Results The prevalence of halitosis was 12% (95%CI: 7% to 18%) and 9% (95%CI 3% to 14%) for the OA and ICP, respectively. At the cut-off point >80 parts per billion (ppb) VSC, the prevalence of halitosis was 18% (95%CI: 12% to 25%). At the cut-off point >65 ppb VSC, sensitivity and specificity were 94% and 76%, respectively. At the cut-off point >140 ppb, sensitivity was 47% and specificity 96%. For the ICP, sensitivity was 14% and specificity 92%. Conclusions VSC presents high sensitivity at the cut-off point of >65 ppb and high specificity at the cut-off point of >140 ppb. ICP had high specificity, but low sensitivity. The OA can express either occasional or chronic bad breath, whereas the ICP can be a potential instrument to detect chronic halitosis.

Halitosis affects all populations worldwide. The presence of chronic halitosis may be related to a health problem. Patients with bad breath usually seek a gastroenterologist and, in some cases, invasive and expensive exams, such as digestive endoscopy, are performed to investigate the etiology of halitosis. This study aimed to investigate whether the prevalence of bad breath in patients diagnosed with dyspepsia (any pain or discomfort in the upper abdomen) is higher than or equivalent to that in non-dyspeptic patients. This is a cross-sectional study that included 312 patients from university hospitals in the city of Rio de Janeiro (141 dyspeptic patients and 171 non-dyspeptic ones). The presence of halitosis was defined based on different cutoff points. Association analyses were performed using a log-binomial model and 95% confidence intervals were calculated for the coefficients, adjusting for sex and age. The equivalence test (Westlake) was used to test the hypothesis of equivalence between the proportions of patients with bad breath in the two groups (dyspeptic vs. non-dyspeptic), considering an equivalence band of ± 15%. The prevalence of bad breath ranged from 30% to 64% according to the definition of bad breath. Dyspepsia was not associated with bad breath in any of the three definitions of bad breath (two specific ones and a sensitive one). The proportion of patients with marked bad breath was equivalent in patients with and without dyspepsia.