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.