Comparing risk estimates of sulphonamide-induced agranulocytosis from the Swedish Drug Monitoring System and a case-control study.
A comparison has been made of risk estimates for agranulocytosis connected with sulphasalazine and trimethoprim-sulphamethoxazole (T-SM) therapy calculated from data in the Swedish Drug Monitoring System ("spontaneous" reports, sales and prescription information) and a population based case-control study (the IAAAS). The relative risk for agranulocytosis during sulphasalazine treatment was calculated to be 107 and 123 by the spontaneous reporting system and the case-control study, respectively. The corresponding excess risk in both systems was 1.8. For T-SM the relative risk was 17 in the spontaneous reporting system and 12 in the case-control study, while the excess risk calculated for 3 days of treatment was 0.9 in the spontaneous reporting system, and 1.6 for 3 or more days of treatment in the case-control study. It is concluded that the Swedish Drug Monitoring System gives an appropriate estimate of the risk of developing agranulocytosis in association with the two drugs studied.
Section of Pharmacoepidemiology, Medical Products Agency, Uppsala, Sweden.
M
M
Keisu
E
E
Ekman
B E
BE
Wiholm
D000293:Adolescent; D000328:Adult; D000368:Aged; D000380:Agranulocytosis / Q000139:chemically induced* / Q000503:physiopathology; D016022:Case-Control Studies; D016903:Drug Monitoring; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012306:Risk; D012460:Sulfasalazine / Q000009:adverse effects*; D013548:Sweden; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000009:adverse effects*
D012460:Sulfasalazine; D015662:Trimethoprim, Sulfamethoxazole Drug Combination