Association between Metformin Use and Cancer Stage at Diagnosis among Elderly Medicare Beneficiaries with Preexisting Type 2 Diabetes Mellitus and Incident Prostate Cancer

Table 4

Codes and algorithms to identify diabetes complication severity index (DCSI) developed by Young et al. and modified by Chang et al.

Complications	ICD-9-CM code	DCSI score
Retinopathy
Diabetic ophthalmologic disease	250.5x	1
Background retinopathy	362.01	1
Other retinopathies	362.1	1
Retinal edema	362.83	1
CSME	362.53	1
Other retinal disorders	362.81, 362.82	1
Proliferative retinopathy	362.02	2
Retinal detachment	361.xx	2
Blindness	369.xx.00–0.99	2
Vitreous hemorrhage	379.23	2
Nephropathy
Diabetic nephropathy	250.4	1
Acute glomerulonephritis	580	1
Nephrotic syndrome	581	1
Hypertension, nephrosis	581.81	1
Chronic glomerulonephritis	582	1
Nephritis/nephropathy	583	1
Chronic renal failure	585
Renal failure NOS	586
Renal insufficiency	593.9
Neuropathy
Diabetic nephropathy	356.9, 250.6	1
Amyotrophy	358.1	1
Cranial nerve palsy	951.0, 951.1, 951.3	1
Mononeuropathy	354.0–355.9	1
Charcot’s arthropathy	713.5	1
Polyneuropathy	357.2	1
Cerebrovascular
TIA	435	1
Stroke	431, 433, 434, 436	2
Cardiovascular
Atherosclerosis	440.xx	1
Other IHD	411	1
Angina pectoris	413	1
Other chronic IHD	414	1
Myocardial infarction	410	2
Ventricular fibrillation, arrest	427.1, 427.3	2
Atrial fibrillation, arrest	427.4, 427.5	2
Other ASCVD	429.2	1
Old myocardial infarction	412	2
Heart failure	428	2
Atherosclerosis, severe	440.23, 440.24	2
Aortic aneurysm/dissection	441	2
Peripheral vascular disease
Diabetic PVD	250.7	1
Other aneurysms, LE	442.3	1
PVD	443.81, 443.9	1
Foot wound + complication	892.1	1
Claudication, intermittent	443.9	1
Embolism/thrombosis (LE)	444.22	2
Gangrene	785.4	2
Gas gangrene	0.4	2
Ulcer of lower limbs	707.1	2
Metabolic
Ketoacidosis	250.1	2
Hyperosmolar	250.2	2
Other comas	250.3	1

Note: the table is adapted from the previous algorithm defined by Young et al. and modified by Change et al. to identify the severity of diabetes using claims database. Severity index was based on a scale ranging from 0 to 2 for each complication as follows: 0 = no abnormality, 1 = some abnormality, and 2 = severe abnormality.
ASCVD, atherosclerotic cardiovascular disease; CSME, cystoid macular edema/degeneration; DCSI, diabetes complications severity index; IHD, ischemic heart disease; ICD-9-CM, international classification of diseases, ninth revision, clinical modification; LE, lower extremity; NOS, not otherwise specified; PVD, peripheral vascular disease; TIA, transient ischemic attack.