Table 1 Admission details.

	Year group			Patient characteristics
	1997–98	1999–2000	2001–02	Total	Length of stay		Gender	Age
	(% all admissions)	(% all admissions)	(% all admissions)	(% all admissions)	(median days)		(male)	(median months)
All admissions	35773	33617	33865	103255	2	58%			57.04
Medical record reviewed	518 (1.5%)	554 (1.6%)	540 (1.6%)	1612 (1.6%)*	7 (p<0.001†)	56% (p = 0.17‡)			13.5 (p<0.001†)
Adverse events detected	146	113	66	271§ (0.3%)	11 (p<0.001¶)	53.5% (p = 0.33**)			13.5 (p = 0.13¶)

*1612 admissions of 1564 patients; 36 patients were reviewed on two separate admissions, 6 patients on three separate admissions.

†Random sample of 51 410 admissions v medical record reviewed, Mann‐Whitney U test.

‡All admissions v medical record reviewed, χ² test.

§271 admissions affecting 268 patients with a total of 325 adverse events detected.

¶Medical record review v adverse event detected, Mann‐Whitney U test.

**Medical record reviewed v adverse event detected, χ² test.