Table 1.
Construction of study cohort
| Sample size n | Criterion | MHC Yes | MHC No |
|---|---|---|---|
| n(%) | n(%) | ||
| 440,953 | Diabetic veteran VA outpatient treated with oral antiglycemic (during the 6 months prior to the OI), who was alive at start of OI and for whom MHC status can be determined | 80,798 | 360,155 |
| ↓ | |||
| 427,335 | VA outpatient use in OI* | 80,745 | 346,590 |
| 100% | 96% | ||
| ↓ | |||
| 426,605 | Non-institutionalized in OI† | 80,344 | 346,261 |
| 100% | 100% | ||
| ↓ | |||
| 426,454 | No data problems‡ | 80,323 | 346,131 |
| 100% | 100% | ||
| ↓ | |||
| 366,066 | No conditions likely to alter goals of care§ | 67,099 | 298,967 |
| 84% | 86% | ||
| ↓ | |||
| 315,063 | Patient’s home facility submitted usable HbA1c lab data to central data repository | 57,309 | 257,754 |
| 85% | 86% | ||
| ↓ | |||
| 269,692 | Had at least one HbA1c test completed during the OI | 51,582 | 218,110 |
| 90% | 85% | ||
| ↓ | |||
| Poor glycemic control: Had at least one HbA1c ≥8 during OI eligible to serve as an index HbA1c: | 20,803 | 71,572 | |
| 36% | 28% | ||
| (1) no antiglycemic intensification in the 3 months prior to the HbA1c test, AND | 18,802 | 65,458 | |
| 90% | 91% | ||
| (2) no hospitalization in the 3 months prior to the HbA1c test, AND | 18,197 | 64,670 | |
| 97% | 99% | ||
| (3) not occurring on a hospital admission day, AND | 18,180 | 64,629 | |
| 100% | 100% | ||
| 58,364 | (4) no insulin prescribed in the 6 months prior to the HbA1c test | 11,581 | 46,783 |
| 64% | 72% | ||
| ↓ | |||
| 52,526 | Final analytic cohort: Testing data set (90% random sample) | 10,422 | 42,104 |
| 90% | 90% |
Legend: This table shows sample size at each step of cohort construction, overall and for those with/ without Mental Health Conditions; % reported in a row refers to % of prior row remaining after applying the inclusion criterion listed in current row.
*Utilization refers to VA face-to-face outpatient care of any type; telephone, laboratory or radiology encounters did not qualify as face-to-face. Note that percentages in each row use the number in the prior row as denominator.
†Did not spend more than half the year in a VA inpatient or long-term care setting.
‡Data quality issues such that unique identifier (scrambled social security number), date of birth or vital status was indeterminate.
§End-stage renal disease, end-stage liver disease, cancer, stroke or dementia diagnosis occurring in the two years prior to the observation interval.
Abbreviations: OI, Observation Interval (April 1, 2003 through March 31, 2004); MHC, Mental Health Condition; HbA1c, Hemoglobin A1c; VA, Veterans Health Administration.