Table 2.

Diagnostic groups used in study and corresponding ICD 9 code⁷

	ICD chapter	Diagnostic group	ICD codes
I	Infectious and parasitic diseases	Infection	1-139
II	Neoplasms	Cancer	140-208
		Benign neoplasms	210-239
III	Endocrine, metabolic, and nutritional diseases	Diabetes	250
		Other endocrine diseases	240-279
IV	Blood and blood forming organs	Blood diseases	280-289
V	Mental disorders	Dementia	290
		Schizophrenia	295
		Depression and anxiety	296, 300
		Alcohol and drugs	291-292, 303-305
		Mental retardation, Down’s syndrome*	317-319, 758.0
		Other mental disorders	Remainder 290-316
VIa	Nervous system	Neurological disorders	320-359
VIb	Sense organs	Eye disorders	360-379
		Ear disorders	380-389
VII	Circulatory system	Hypertension	401-405
		Coronary heart diseases	410-414
		Heart failure	428-429
		Stroke	430-438
		Other circulatory diseases	Remainder 390-459
VIII	Respiratory system	Asthma and chronic obstructive airways disease	490-496
		Other respiratory diseases	460-489, 497-519
IX	Digestive system	Dental diseases	520-529
		Gastrointestinal diseases	531-569
		Liver, gall, pancreatic diseases	570-579
Xa	Urinary system	Urinary disorders	580-599
Xb	Genital organs	Genital disorders	600-629
XI	Pregnancy and childbirth†	Pregnancy	630-676
XII	Skin diseases	Skin diseases	680-709
XIII	Musculoskeletal system	Musculoskeletal diseases	710-739
XIV/XV	Perinatal/congenital conditions†	Perinatal/congenital conditions	740-779
XVI	Symptoms, signs, and ill defined conditions	Ill defined conditions	780-899
XVII	Accidents	Falls	E880-888
		Other accidents	E800-879, E890-999
		Not allocated
		Non-specific‡

^*Down’s syndrome is classified in ICD chapter XV, code 758.0. ^†Hospital costs of healthy babies (boys and girls) after childbirth were assigned to pregnancy and childbirth (women). ^‡Costs of healthcare administration and living costs in old people’s homes.