Blasi F, Allegra L, Tarsia P, et al
Thorax 1998; 53:1095-1096*
Discussion about a report of C. pneumoniae association with severe “brittle” asthma, but not with “ordinary” acute asthma exacerbations. A methodological concern was poor matching (by age and sex) of cases and controls. Another issue not mentioned here is the inadvisability of choosing hospital controls instead of outpatient controls.