Out-of-season recollection of drug use for seasonal IgE-mediated rhinitis: useful but an overestimation.
BACKGROUND
The history of seasonal, IgE-mediated (allergic) rhinitis is often obtained postseasonally as a retrospective assessment. It is not known whether recollected drug use is representative for the in-seasonal medication history.


OBJECTIVE
To investigate the agreement between in-seasonal and out-seasonal reports on drugs and drug doses, and to investigate whether retrospective assessment was sufficiently sensitive to detect the effect of intervention.


METHODS
Thirty-five patients allergic to birch pollen were allocated to allergen-specific immunotherapy (SIT) or placebo in a double-blind study. Drug use was recorded daily during the season 2000 and out-seasonally 6 months after the seasons 1999 and 2000. The mean daily drug use was transformed into a 4-point categorical scale for simplicity and was calculated for the out-seasonal rating and for 6 in-seasonal periods of different durations. In-seasonal and postseasonal ratings were compared with the Cohen weighted kappa (kappa w).


RESULTS
We observed a high level of agreement between in-seasonal and retrospective reports of drugs used (kappa w > 0.60) and drug doses (kappa w > 0.50). The highest agreement was observed for the in-seasonal day, week, or 2 weeks with the highest drug intake. Out-seasonal ratings significantly overestimated the daily oral and nasal antihistamine use compared with in-seasonal periods >2 weeks. Despite being comparable pretreatment, only the SIT group had a significant decrease in recollected total drug use during SIT.


CONCLUSIONS
Out-seasonal recollection of hay fever drugs represented a period of a maximum 14 days. It appeared sufficiently sensitive to detect the effect of intervention.
Bodtger
Uffe
U
Allergy Clinic, National University Hospital, Blegdamsvej 9, DK-2100 Copenhagen, Denmark. ub@dadlnet.dk
Malling
Hans-Jørgen
HJ
Poulsen
Lars K
LK
D000328:Adult; D018926:Anti-Allergic Agents / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology; D008297:Male; D008568:Memory; D008875:Middle Aged; D015203:Reproducibility of Results; D006255:Rhinitis, Allergic, Seasonal / Q000188:drug therapy*; D013997:Time Factors
D018926:Anti-Allergic Agents; D007073:Immunoglobulin E