Table 1

Summary of study methods

A. Data sources for the study


Data sources

Period

Records

Persons

Key variables


1. Medicare benefits (MBS)

1984 to 2006

143,416,764

554,541

GP and pathology services

2. Pharmaceutical benefits (PBS)

1990 to 2006

78,467,656

475,826

Prescriptions

3. Hospital inpatients*

1980 to 2006

4,844,745

520,236

Dates, diagnoses and procedures

4. Mental health registry (MHR)

Dates and diagnoses

- Mental health inpatients*

1966 to 2006

529,935

150,401

- Mental health outpatients and community

1971 to 2006

9,981,236

190,440

5. Electoral roll registrations

1988 to 2006

782,161

483,524

Date of registration and updates

6. Death*

1990 to 2006

80,546

80,546

Date of death and cause of death

7. Emergency department*

2001 to 2006

990,506

248,457

Date of attendance and diagnosis


B. Data sources and codes for identifying diabetes


Hospital inpatient and ED

ICD-9 code in any diagnosis field


- Diabetes

250

- Polycystic ovary syndrome

256.4


PBS

Item


- Oral hypoglycaemic agents

1202, 1801, 2178, 2430, 2440, 2449, 2607, 2720, 2939, 2940, 8188, 8189, 8391, 8392, 8450, 8451, 8452, 8533, 8535, 8607, 8687, 8688, 8689, 8690, 8691, 8692, 8693, 8694, 8695, 8696, 8810, 8811, 8838, 8884

- Insulin

1425, 1426, 1429, 1430, 1431, 1461, 1462, 1531, 1532, 1533, 1534, 1535, 1537, 1591, 1592, 1710, 1711, 1713, 1715, 1716, 1718, 1721, 1722, 1761, 1762, 1763, 2061, 2062, 8006, 8084, 8085, 8212, 8390, 8435, 8571, 8609, 8874, 9039, 9094


MBS

Item


- GP diabetes annual cycle of care

2517, 2518, 2521, 2522, 2525, 2526, 2620, 2622, 2624, 2631, 2633, 2635

- HbA1c or fructosamine

66551, 66554, 66557, 66319, 66322, 73815, 73840


C. Category of mental disorders


Category

ICD-9 principal code


- Alcohol/drug disorders

291, 292, 303 to 305

- Schizophrenia

295

- Affective psychoses

296

- Other psychoses

293, 294, 297 to 299

- Neurotic disorders

300

- Personality disorders

301

- Adjustment reaction

309

- Depressive disorder

311

- Other mental disorders

302, 306 to 308, 310, 312 to 319

- Other than mental or behavioural disorders

not in 290 to 319


D. MBS items for identifying pathology tests for routine diabetes monitoring


Test

Item


Glycated haemoglobin (HbA1c)

66551, 66319

Microalbuminuria

66361, 66560

Lipids

66317, 66334, 66335, 66337, 66339, 66341, 66521, 66524, 66527, 66530, 66533, 66536


E. ICD-9 codes for identifying diabetes complications and diabetes-related deaths


ICD-9 principal diagnosis or procedure codes


Diabetes/diabetes complications

250

Circulatory disorders

- Hypertension

401 to 405

- Ischemic heart disease

410 to 414

- Cerebrovascular disease

430 to 438, 362.34, 784.3

- Heart failure

428, 429.2 to 429.3, 429.9

- Atherosclerosis

440

- Peripheral vascular disease

443, 459.8 to 459.9, 444, 447.1

Visual disorders

- Glaucoma

365

- Cataract

366

- Blindness

369

Other disorders

- Nephropathy

580 to 586, V45.1, V56

Other renal complications

- Infections of kidney

590

- Cystitis, urinary tract infection

595, 599.0

- Proteinuria

791.0

- Neuropathy/other neurologic symptoms

354, 355, 356.8, 729.2

- Chronic skin ulcer

707

- Gangrene

785.4

- Nontraumatic lower-extremity amputation

84.1, 84.3

Other complications

- Candidiasis of vulva and vagina

112.1

- Chronic osteomyelitis of the foot

730.17


Abbreviations: ED, emergency department; ICD-9, The International Classification of Diseases, ninth revision* In these datasets, ICD-9 was used for 1980-1987, ICD-9-CM for 1988 to June 1999, and ICD-10-AM from July 1999 onwards. We back mapped ICD-9-CM and ICD-10-AM codes to corresponding ICD-9 codes for this study.

Mai et al. BMC Medicine 2011 9:118   doi:10.1186/1741-7015-9-118

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