Purpose: An older female predominance has been reported among chronic cough patients in Western countries, which is considered to be associated with a higher cough sensitivity in females. However, the characteristics of Chinese chronic cough patients remain unclear. This study aimed to explore the age and sex distribution as well as their relationship with cough reflex sensitivity to capsaicin in Chinese chronic cough patients. Methods: We analyzed the demographic features of 1,882 consecutive chronic cough patients who attended our cough clinic in Guangzhou, China. Cough sensitivity to capsaicin, which was defined as the lowest concentration of capsaicin causing 5 coughs or more (C5), was measured in 539 of the 1,882 patients and 68 healthy volunteers. Results: The mean age of the patients was 43.0 ± 13.7 years and patients aged <50 years accounted for more than two-thirds of the study population. Around 87% of the patients were never-smokers. The proportion of females (51.5%) was almost equal to that of males (48.5%). The pattern of the age and sex distribution was consistently reflected within most common causes of chronic cough, while a female predominance was shown in patients with coughvariant asthma and patients aged ≥50 years. Female patients had higher cough sensitivity to capsaicin than male patients (log C5: 1.58 ± 0.84 vs. 2.04 ± 0.84 μmol/L, P = 0.001), and patients aged ≥50 years had higher cough sensitivity to capsaicin than patients aged <50 years. Conclusions: In China, patients with chronic cough have a roughly equal sex distribution and a middle-aged predominance, irrespective of a higher cough sensitivity to capsaicin in females and older patients.

BackgroundHigh-flow nasal cannula (HFNC) can be used as an initial support strategy for patients with acute respiratory failure (ARF) and after extubation. However, no clear evidence exists to support or oppose HFNC use in clinical practice. We summarized the effects of HFNC, compared to conventional oxygen therapy (COT) and noninvasive ventilation (NIV), on important outcomes including treatment failure and intubation/reintubation rates in adult patients with ARF and after extubation.MethodsWe searched 4 electronic databases (Pubmed, EMBASE, Scopus, and Web of Science) to identify randomized controlled trials (RCTs) comparing the effects of HFNC with either COT or NIV on rates of 1) treatment failure and 2) intubation/reintubation in adult critically ill patients.ResultsWe identified 18 RCTs (n = 4251 patients) in pooled analyses. As a primary mode of support, HFNC treatment reduced the risk of treatment failure [Odds Ratio (OR) 0.65; 95% confidence interval (CI) 0.43–0.98; p = 0.04; I2 = 32%] but had no effect on preventing intubation (OR, 0.74; 95%CI 0.45–1.21; p = 0.23; I2 = 0%) compared to COT. When used after extubation, HFNC (vs. COT) treatment significantly decreased reintubation rate (OR 0.46; 95%CI 0.33–0.63; p < 0.00001; I2 = 30%) and extubation failure (OR 0.43; 95%CI 0.25–0.73; p = 0.002; I2 = 66%). Compared to NIV, HFNC significantly reduced intubation rate (OR 0.57; 95%CI 0.36–0.92; p = 0.02; I2 = 0%) when used as initial support, but did no favorably impact clinical outcomes post extubation in few trials.ConclusionsHFNC was superior to COT in reducing treatment failure when used as a primary support strategy and in reducing rates of extubation failure and reintubation when used after extubation. In few trials, HFNC reduced intubation rate compared to NIV when used as initial support but demonstrated no beneficial effects after extubation.Electronic supplementary materialThe online version of this article (10.1186/s12931-018-0908-7) contains supplementary material, which is available to authorized users.

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