Meteorological effects on severe hemoptysis: A hospital-based observational study

Background: Although some meteorological factor are likely to contribute to the onset of hemoptysis, few studies have investigated this issue, with none conducted in the Asia-Pacific region. Therefore, the present study aimed to evaluate the associations of meteorological factors with the occurrence of hemoptysis. Differences in the frequency of hemoptysis among several calendar variables were also assessed. Methods: A total of 47 hemoptysis patients aged ≥ 20 years undergoing bronchial artery embolization in Kyushu Central Hospital of the Mutual Aid Association of Public School Teachers from January 2012 to December 2017 were included in the study. All hemoptysis events were assembled in a single time series, and the proportion of hemoptysis days was 2.1%. The associations of meteorological variables with hemoptysis days were estimated as odds ratios with 95% confidence intervals by using multivariable-adjusted logistic regression models. The frequency of hemoptysis days was compared among several calendar variables using a chi-square test. Results: Mean relative humidity was negatively associated with hemoptysis (P for trend = 0.02). The inverse association remained significant when only the hemoptysis events with no infectious lung diseases were used (P for trend=0.02). No significant difference was observed in the occurrence of hemoptysis among seasons, months, or other calendar variables (all P ≥ 0.21). Conclusions: Lower relative humidity was a significant risk factor for the development of hemoptysis. Clinicians should be aware of the potential for increases in hemoptysis events on days with low ambient humidity.