Table 1 Weighted incidence of adverse events (AEs) in patients admitted to Dutch hospitals in 2004 by hospital type, both for the total sample (discharged patients and deceased patients) and for the subgroup of deceased patients

	Hospital type
	University	Tertiary teaching	General	Total sample
Total sample* (n = 7926)
No of records reviewed	1378	2342	4206	7926
No of records with AEs	171	187	305	663
Weighted AE incidence, % (95% CI)	7.6 (5.9 to 9.8)	6.7 (5.5 to 8.1)	4.8 (4.1 to 5.7)	5.7 (5.1 to 6.4)
No of records with preventable AEs	37	90	156	283
Weighted preventable AE incidence, % (95% CI)	1.6 (0.9 to 2.9)	2.8 (2.1 to 3.8)	2.2 (1.7 to 2.8)	2.3 (1.9 to 2.7)
Deceased patients† (n = 3983)
No of records reviewed	780	1155	2048	3983
No of records with AEs	129	110	208	447
Weighted AE incidence, % (95% CI)	16.5 (14.1 to 19.3)	9.5 (8.0 to 11.4)	10.2 (8.9 to 11.5)	10.7 (9.8 to 11.7)
No of records with preventable AEs	28	58	114	200
Weighted preventable AE incidence, % (95% CI)	3.6 (2.5 to 5.2)	5.0 (3.9 to 6.4)	5.6 (4.7 to 6.6)	5.2 (4.5 to 5.9)
No of records with preventable AEs that contributed to the death of the patient	19	48	90	157
Weighted incidence of preventable AEs that contributed to the death of the patient, % (95% CI)	2.4 (1.6 to 3.8)	4.2 (3.1 to 5.5)	4.4 (3.6 to 5.4)	4.1 (3.5 to 4.8)

*Incidence rates and 95% CIs were weighted for oversampling of deceased patients and of patients admitted to a university hospital.
†Incidence rates and 95% CIs were weighted for oversampling of deceased patients admitted to a university hospital.