Study objective: To determine the potential
role of seasonality in hospitalizations for cryptogenic and
noncryptogenic hemoptysis in the French population.
Design: Retrospective analysis of hospital discharge data
from a National Register.
Setting: All 29 French
university hospitals, between July 1, 1994, and June 30, 1997.
Patients: Two thousand six hundred seventy-seven and 3,672
adult hospitalizations for cryptogenic and other hemoptysis,
Measurements: Cumulative monthly
averages were determined, expressed as the percentage above or below
the average monthly value during the entire study period.
Results: The distribution of cumulative monthly
hospitalizations for cryptogenic hemoptysis peaked in March (32% above
the average) and was lowest in summer (30% below the average;
p < 0.001). Hospitalizations for noncryptogenic hemoptysis followed
a similar seasonal pattern (p < 0.001). In the 16- to 34-year-old
individuals, cryptogenic hemoptysis, compared with noncryptogenic
hemoptysis, showed a higher incidence with a larger seasonal amplitude
(p < 0.001).
Conclusions: A better understanding of
the fundamental pathophysiologic mechanisms underlying this respiratory
and hemorrhagic condition may be helpful in developing preventive
measures, especially in patients with a risk of