Table 1. Characteristics of Study Participants at Baselinea.
| Variable | Control | Treatment |
|---|---|---|
| Characteristics of Prescribers | (n = 2528) | (n = 2527) |
| Quetiapine days supplied in 9-mo baseline period, mean (SD) | ||
| To all patients | 2960 (2669) | 2872 (2401) |
| To new patients | 229 (260) | 225 (243) |
| To low-value patients | 846 (1307) | 794 (1250) |
| To guideline-concordant patients | 786 (924) | 769 (798) |
| Prescriber enrolled to bill Original Medicare, No. (%)b | 1745 (69.0) | 1784 (70.6) |
| Female sex, No. (%) | 447 (17.7) | 453 (17.9) |
| Specialty, No. (%) | ||
| General practitioner | 104 (4.1) | 127 (5.0) |
| Family medicine | 1186 (46.9) | 1242 (49.1) |
| Internal medicine | 1238 (49.0) | 1158 (45.8) |
| Characteristics of Baseline Patients | (n = 45 589) | (n = 43 911) |
| No. of patients by patient group | ||
| Low value | 12 105 | 11 385 |
| Guideline concordant | 13 050 | 12 630 |
| Quetiapine days received in 9-mo baseline period, mean (SD) | 193 (118) | 192 (117) |
| Quetiapine days received by patient group, mean (SD)c | ||
| Low value, 26.2% of 89 500 patients | 191 (116) | 189 (116) |
| Guideline concordant, 28.7% of 89 500 patients | 202 (118) | 203 (115) |
| Age, mean (SD), y | 70.4 (16.2) | 70.3 (16.2) |
| Nonwhite race/ethnicity, No. (%) | 13 415 (29.4) | 13 200 (30.1) |
| Female sex, No. (%) | 29 144 (63.9) | 27 963 (63.7) |
| Dementia or Alzheimer disease, No. (%) | 20 790 (45.6) | 19 558 (44.5) |
| Major psychiatric illness, No. (%) | 21 735 (47.7) | 20 803 (47.4) |
| Institutionalized in a long-term care facility, No. (%) | 7178 (15.7) | 6468 (14.7) |
| Qualifies for Medicare by disability, No. (%) | 17 028 (37.4) | 16 315 (37.2) |
| Dual Medicare-Medicaid eligible, No. (%) | 27 222 (59.7) | 26 158 (59.6) |
No. (%) is the number of observations (percentage of observations). The mean (SD) of days supplied or received refer to quetiapine fills in the baseline period, the 9 months before the intervention began. The only significant difference in control vs treatment baseline characteristics was in prescriber specialty (P = .04). The sample was the 5055 study prescribers (prescriber rows) and 89 500 patients (patient rows).
Original Medicare is the government health care payer in Medicare and is also called fee-for-service Medicare.
The low-value and guideline-concordant patient shares do not sum to 100% because they exclude patients who carried both low-value and guideline-concordant diagnoses (18.8% [16 858 of 89 500] of baseline patients), neither a low-value nor a guideline-concordant diagnosis (24.0% [21 521 of 89 500] of patients), or no diagnosis data in 2013 and 2014 (2.2% [1951 of 89 500] of patients).