Table 3.

Historical incidence of allopurinol induced SCARs in 2001-04, compared with incidence among study participants

Variable	Year
	2001	2002	2003	2004
No of new recipients of allopurinol	137 380	117 896	107 873	102 060
No of participants with allopurinol induced SCARs	438	348	307	295
Incidence (%) of allopurinol induced SCARs (95% CI)	0.32% (0.29% to 0.35%)	0.30% (0.27% to 0.33%)	0.28% (0.25% to 0.32%)	0.29% (0.26% to 0.32%)
P value comparing historical incidence and actual incidence among study participants*	0.0018	0.0026	0.0038	0.0040

SCARs=severe cutaneous adverse reactions.

*P values calculated by the two side, one sample binomial test.