Table 1.

Operational Definitions for the VISN 10 Diabetes Registry

Step 1: Define patients with diabetes mellitus in VISN 10a
From October 1, 2001 to present, the patient had any combination of ICD-9-CM diagnosis codes (250.xx, 357.2, 362.0, 366.41) on at least three separate dates of clinical encounters
or
From October 1, 2001 to present, the patient had a diabetes-specific medicationb dispensed from a VISN 10 pharmacy on at least two separate dates
Step 2: Define active patients versus not active patients with diabetes
Active patients	Not active patients
Date of death = null and at least one of two conditions met:	If conditions for active are not met, then patient is not active
1. The patient had a primary care clinic visit within the past 18 months
or
2. The patient had a diabetes-specific medicationb dispensed from a VISN 10 pharmacy within the past 18 months
Step 3: Define the clinic group most responsible for diabetes care for each active patient
Active patients
Find the most recent primary care clinic visit within the past 18 months. Based on the location of the visit, assign the patient to:
Site (a mutually exclusive list of five VHA sites in Ohio)
Chillicothe
Cincinnati
Cleveland
Dayton
Columbus
Clinic group (a subset of clinics within each site)
If the patient has no primary care clinic visits within the past 18 months, then classify as unassigned

^aVISN 10 is the VA Integrated Service Network 10.

^bDiabetes-specific medications are any sulfonylurea, biguanide, thiazolidenedione, metiglinide, α-glucosidase inhibitor, insulin, or glucose meter test strips.