Table 1 .
Baseline distribution of HbA1c testing frequencies in patients with stable and controlled type 2 diabetes. Data are no (%) of patients per testing frequency category
| HbA1c testing frequency | P | |||
|---|---|---|---|---|
| Recommended (≤2 per year) | Frequent (3-4 per year) | Excessive (≥5 per year) | ||
| Patients in each testing category (n=31 545; 100%) | 12 535 (39.7) | 17 182 (54.5) | 1828 (5.8) | — |
| Patient age (years) | ||||
| 18-44 (n=3561; 11.3%) | 1711(48.1) | 1684 (47.3) | 166 (4.7) | <0.001 |
| 45-54 (n=8130; 25.8%) | 3404 (41.9) | 4314 (53.1) | 412 (5.1) | |
| 55-64 (n=11 781; 37.4%) | 4502 (38.2) | 6586 (55.9) | 693 (5.9) | |
| 65-74 (n=4643; 14.7%) | 1660 (35.8) | 2666 (57.4) | 317 (6.8) | |
| ≥75 (n=3430; 10.9%) | 1258 (36.7) | 1932 (56.3) | 240 (7.0) | |
| Sex | ||||
| Male (n=16 060; 50.9%) | 6448 (40.2) | 8664 (53.9) | 948 (5.9) | 0.16 |
| Female (n=15 485; 49.1%) | 6087 (39.3) | 8518 (55.0) | 880 (5.7) | |
| Race or ethnic origin | ||||
| White (n=18 190; 57.7%) | 7242 (39.8) | 9919 (54.5) | 1029 (5.7) | <0.001 |
| Black (n=4757; 15.1%) | 2042 (42.9) | 2481 (52.2) | 234 (4.9) | |
| Hispanic (n=3482; 11.0%) | 1442 (41.4) | 1852 (53.2) | 188 (5.4) | |
| Asian (n=2243; 7.1%) | 834 (37.2) | 1280 (57.1) | 129 (5.8) | |
| Unknown (n=2873; 9.1%) | 975 (33.9) | 1650 (57.4) | 248 (8.6) | |
| US census region | ||||
| Midwest (n=3675; 11.7%) | 1545 (42.0) | 1985 (54.0) | 145 (4.0) | <0.001 |
| Northeast (n=7954; 25.2%) | 2782 (35.0) | 4467 (56.2) | 705 (8.9) | |
| South (n=17 481; 55.4%) | 7113 (40.7) | 9512 (54.4) | 856 (4.9) | |
| West (n=2433; 7.7%) | 1095 (45.0) | 1217 (50.0) | 121 (5.0) | |
| Unknown (n=2; 0.0%) | 0 | 1 (50.0) | 1 (50.0) | |
| Comorbidities | ||||
| Myocardial infarction (n=383; 1.2%) | 125 (32.6) | 227 (59.3) | 31 (8.1) | 0.01 |
| Heart failure (n=720; 2.3%) | 251 (34.9) | 403 (56.0) | 66 (9.2) | <0.001 |
| Kidney disease (n=655; 2.1%) | 211 (32.2) | 372 (56.8) | 72 (11.0) | <0.001 |
| Cancer (n=2073; 6.6%) | 728 (35.1) | 1176 (56.7) | 169 (8.2) | <0.001 |
| Charlson comorbidity index | ||||
| 0-1 (n=19 411; 61.5%) | 8316 (42.8) | 10225 (52.7) | 870 (4.5) | <0.001 |
| 2 (n=4814; 15.3%) | 1836 (38.1) | 2646 (55.0) | 332 (6.9) | |
| 3 (n=4316; 13.7%) | 1468 (34.0) | 2515 (58.3) | 333 (7.7) | |
| ≥4 (n=3004; 9.5%) | 915 (30.5) | 1796 (59.8) | 293 (9.8) | |
| Index HbA1c | ||||
| ≤5.6% (n=3283; 10.4%) | 1599 (48.7) | 1498 (45.6) | 186 (5.7) | <0.001 |
| 5.7-6.4% (n=18 016; 57.1%) | 7445 (41.3) | 9601 (53.3) | 970 (5.4) | |
| 6.5-6.9% (n=10 246; 32.5%) | 3491 (34.1) | 6083 (59.4) | 672 (6.6) | |
| Baseline treatment | ||||
| Lifestyle (n=10 370; 32.9%) | 4798 (46.3) | 5069 (48.9) | 503 (4.9) | <0.001 |
| 1 drug (n=11 883; 37.7%) | 4617 (38.9) | 6572 (55.3) | 694 (5.8) | |
| 2 drugs (n=6711; 21.3%) | 2383 (35.5) | 3920 (58.4) | 408 (6.1) | |
| ≥3 drugs (n=2581; 8.2%) | 737 (28.6) | 1621 (62.8) | 223 (8.6) | |
| Treatment change | ||||
| No change before or after; lifestyle (n=8976; 28.5%) | 4245 (47.3) | 4328 (48.2) | 403 (4.5) | <0.001 |
| No change before or after; treated with at least one drug (n=16 746; 53.1%) | 6246 (37.3) | 9546 (57.0) | 954 (5.7) | |
| Drug class change only (n=247; 0.8%) | 59 (23.9) | 158 (64.0) | 30 (12.2) | |
| Intensification (n=2644; 8.4%) | 900 (34.0) | 1515 (57.3) | 229 (8.7) | |
| Deintensification (n=2932; 9.3%) | 1085 (37.0) | 1635 (55.8) | 212 (7.2) | |
| Specialties seen* | ||||
| Primary care (n=30 331; 96.2%) | 12 062 (39.8) | 16 554 (54.6) | 1715 (5.7) | <0.001 |
| Endocrinology (n=4225; 13.4%) | 1044 (24.7) | 2626 (62.2) | 555 (13.1) | <0.001 |
| Cardiology (n=8237; 26.1%) | 2828 (34.3) | 4755 (57.7) | 654 (7.9) | <0.001 |
| Ophthalmology (n=5772; 18.3%) | 1967 (34.1) | 3396 (58.8) | 409 (7.1) | <0.001 |
| Gynecology (n=6601; 20.9%) | 2462 (37.3) | 3717 (56.3) | 422 (6.4) | <0.001 |
| Nephrology (n=1433; 4.5%) | 419 (29.2) | 838 (58.5) | 176 (12.3) | <0.001 |
| Laboratory studies obtained on the same day | ||||
| HbA1c with or without glucose (n=16 149; 51.2%) | 5866 (36.3) | 9115 (56.4) | 1168 (7.2) | <0.001 |
| Bundled tests (n=15 396; 48.8%)† | 6669 (43.3) | 8067 (52.4) | 660 (4.3) | |
| Coordination of care | ||||
| Primary care only (n=3927; 12.5%) | 1906 (48.5) | 1909 (48.6) | 112 (2.9) | <0.001 |
| Primary care and specialist care (n=26 404; 83.7%) | 10 156 (38.5) | 14 645 (55.5) | 1603 (6.1) | |
| Specialist care only (n=1109; 3.5%) | 436 (39.3) | 576 (51.9) | 97 (8.8) | |
| None (n=105; 0.3%) | 37 (35.2) | 52 (49.5) | 16 (15.2) | |
| Encounters per year | ||||
| Median (interquartile range) | 5.5 (3.5-9.0) | 7.5 (5.0-11.5) | 11.0 (7.5-16.0) | <0.001 |
| Range | 0.0-76.5 | 0.0-73.0 | 0.0-124.0 | |
| Year of index HbA1c test | ||||
| 2001-02 (n=776; 2.5%) | 220 (28.4) | 485 (62.5) | 71 (9.5) | <0.001 |
| 2003-04 (n=1827; 5.8%) | 750 (41.1) | 978 (53.5) | 99 (5.5) | |
| 2005-06 (n=2922; 9.3%) | 1258 (43.1) | 1498 (51.3) | 166 (5.7) | |
| 2007-08 (n=9203; 29.2%) | 3240 (35.2) | 5345 (58.1) | 618 (6.8) | |
| 2009-10 (n=12 648; 40.1%) | 5261 (41.6) | 6697 (53.0) | 690 (5.5) | |
| 2011 (n=4169; 13.2%) | 1806 (43.3) | 2179 (52.3) | 184 (4.4) | |
*Each patient could see different specialties of healthcare providers, and could be included in one or more categories; percentages therefore add up to more than 100%.
†Bundled tests include lipid profile (n=10 668; 33.8%) and serum creatinine with or without urine microalbumin (n=4728; 15.0%).