TABLE 2.
Baseline Clinical Characteristics (January 2010-December 2010)
| Characteristic | Baseline Adherent | Baseline Nonadherent | ||||
|---|---|---|---|---|---|---|
| Status Change n = 31,320 | No Status Change n = 112,896 | P Value | Status Change n = 39,284 | No Status Change n = 54,902 | P Value | |
| Adherence to OAD medications | ||||||
| PDC, mean (SD) | 0.90 (0.1) | 0.92 (0.1) | < 0.001a | 0.59 (0.2) | 0.54 (0.2) | < 0.001b |
| Adherent (PDC ≥ 80%), n (%) | 31,320 (21.7) | 112,896 (78.3) | < 0.001b | 39,284 (41.7) | 54,902 (58.3) | < 0.001b |
| Copay of last OAD during baseline period, $ | ||||||
| Mean (SD) | 15 (54) | 18 (60) | < 0.001a | 13 (43) | 14 (42) | < 0.001a |
| Median (IQR) | 3 (10) | 4 (8) | – | 4 (8) | 4 (10) | – |
| Final A1c laboratory value, n (%) | ||||||
| Under control | 5,814 (18.6) | 19,542 (17.3) | < 0.001b | 6,914 (17.6) | 9,874 (18.0) | < 0.001b |
| Uncontrolled | 2,167 (6.9) | 8,675 (7.7) | 3,163 (8.1) | 4,391 (8.0) | < 0.001b | |
| Unknown | 23,339 (74.5) | 84,679 (75.0) | 29,207 (74.4) | 40,637 (74.0) | < 0.001b | |
| Comorbid conditions, n (%) | ||||||
| Cardiovascular disease | 6,295 (20.1) | 21,066 (18.7) | < 0.001b | 7,722 (19.7) | 10,171 (18.5) | < 0.001b |
| Nephropathy | 3,625 (11.6) | 13,878 (12.3) | < 0.001b | 4,422 (11.3) | 6,007 (10.9) | < 0.001b |
| Neuropathy | 4,024 (12.9) | 14,512 (12.9) | < 0.001b | 4,613 (11.7) | 6,540 (11.9) | < 0.001b |
| Retinopathy | 2,071 (6.6) | 7,831 (6.9) | < 0.001b | 2,366 (6.0) | 3,121 (5.7) | < 0.001b |
| Obesity | 1,934 (6.2) | 6,449 (5.7) | < 0.001b | 2,650 (6.8) | 3,563 (6.5) | < 0.001b |
| Depression | 1,649 (5.3) | 5,271 (4.7) | < 0.001b | 2,327 (5.9) | 3,218 (5.9) | < 0.001b |
| Chronic kidney disease | 2,794 (8.9) | 10,779 (9.6) | < 0.001b | 3,328 (8.5) | 4,550 (8.3) | < 0.001b |
| Diabetes-related complications, n (%) | ||||||
| Bariatric surgery | 0 | 0 | – | 0 | 0 | – |
| Lower extremity amputation | 0 | 0 | – | 0 | 0 | – |
| Emergent hypoglycemic event | 606 (1.9) | 1,846 (1.6) | < 0.001b | 669 (1.7) | 972 (1.8) | < 0.001b |
| Comorbidity scores, mean (SD) | ||||||
| DCCI | 1.08 (1.7) | 1.06 (1.7) | < 0.001a | 1.05 (1.6) | 1.03 (1.6) | 0.351a |
| DCSI | 0.94 (1.6) | 0.93 (1.7) | < 0.001a | 0.91 (1.6) | 0.87 (1.6) | 0.003a |
| CDS | 8.31 (2.9) | 8.34 (2.9) | 0.094a | 8.22 (3.0) | 7.99 (3.0) | < 0.001a |
| RxRisk-V | 2.16 (2.2) | 2.35 (2.3) | < 0.001a | 2.04 (2.2) | 1.95 (2.1) | < 0.001a |
| Oscillation status, n (%) | 13,347 (42.9) | 30,506 (27.0) | < 0.001b | 42,250 (77.0) | 24,866 (63.3) | < 0.001b |
| Medication use | ||||||
| Number of antidiabetic classes used, mean (SD) | 1.45 (0.6) | 1.63 (0.7) | < 0.001a | 1.37 (0.6) | 1.29 (0.5) | < 0.001a |
| Use of each antidiabetic class, n (%) | ||||||
| Biguanides | 24,456 (78.1) | 89,409 (79.2) | < 0.001b | 30,612 (77.9) | 42,227 (76.9) | < 0.001b |
| Sulfonylureas | 16,417 (52.4) | 71,265 (63.1) | < 0.001b | 18,419 (46.9) | 22,235 (40.5) | < 0.001b |
| Thiazolidinediones | 5,062 (16.2) | 25,191 (22.3) | < 0.001b | 5,380 (13.7) | 7,975 (14.5) | < 0.001b |
| Amylin agonists | 0 | 0 | – | 0 | < 10 (0.0) | < 0.001b |
| Meglitinides | 314 (1.0) | 472 (0.4) | < 0.001b | 527 (1.3) | 1,454 (2.7) | < 0.001b |
| Alpha-glucosidase inhibitors | 179 (0.6) | 313 (0.3) | < 0.001b | 172 (0.4) | 436 (0.8) | < 0.001b |
| Glucagone-like peptide-1 receptor agonists | 388 (1.2) | 610 (0.5) | < 0.001b | 356 (0.9) | 619 (1.1) | < 0.001b |
| DPP-4 inhibitors | 754 (2.4) | 4,793 (4.3) | < 0.001b | 1,140 (2.9) | 994 (1.8) | < 0.001b |
| Insulin (subgroup analysis only) | 0 | 0 | – | 0 | 0 | – |
| Last OAD class used during the baseline period, n (%) | ||||||
| Biguanides | 15,978 (51.0) | 52,283 (46.3) | < 0.001b | 21,612 (55.0) | 30,643 (55.8) | < 0.001b |
| Sulfonylureas | 10,705 (34.2) | 40,896 (36.2) | < 0.001b | 12,235 (31.1) | 14,305 (26.1) | < 0.001b |
| Thiazolidinediones | 2,099 (6.7) | 10,629 (9.4) | < 0.001b | 2,437 (6.2) | 3,732 (6.8) | < 0.001b |
| Meglitinides | 90 (0.3) | 132 (0.1) | < 0.001b | 120 (0.3) | 925 (1.7) | < 0.001b |
| Alpha-glucosidase inhibitors | 43 (0.1) | 113 (0.1) | < 0.001b | 57 (0.2) | 232 (0.4) | < 0.001b |
| DPP-4 inhibitors | 70 (0.2) | 355 (0.3) | < 0.001b | 127 (0.3) | 203 (0.4) | < 0.001b |
| Biguanide + DPP-4 inhibitor | 0 | 0 | – | 1 (0.0) | 1 (0.0) | < 0.001b |
| Biguanide+ meglitinide | 1,590 (5.1) | 5,297 (4.7) | < 0.001b | 1,569 (4.0) | 2,923 (5.3) | < 0.001b |
| Biguanide + sulfonylurea | 570 (1.8) | 2,020 (1.8) | < 0.001b | 708 (1.8) | 1,609 (2.9) | < 0.001b |
| Biguanide + thiazolidinediones | 175 (0.6) | 1,171 (1.0) | < 0.001b | 418 (1.1) | 329 (0.6) | < 0.001b |
| Use of mail order pharmacy for fills of antidiabetic medications, n (%) | 23,409 (74.7) | 57,345 (50.8) | < 0.001b | 22,282 (56.7) | 30,471 (55.5) | < 0.001b |
| Number of claims for 90-day supply of antidiabetic medications, mean (SD) | 3.41 (2.9) | 2.35 (3.0) | < 0.001a | 1.76 (2.1) | 1.64 (2.0) | < 0.001a |
| Pill burden, mean (SD) | ||||||
| Diabetes-related pill burden | 1.19 (0.4) | 1.35 (0.5) | < 0.001a | 0.75 (0.4) | 0.67 (0.3) | < 0.001a |
| Total pill burden | 5.52 (2.5) | 5.78 (2.5) | < 0.001a | 4.60 (2.3) | 4.07 (2.2) | < 0.001a |
| Longest medication gap, mean (SD) | 16.53 (15.9) | 11.42 (12.5) | < 0.001a | 34.52 (39.7) | 45.78 (43.1) | < 0.001a |
| Number of pharmacies used, mean (SD) | 28.02 (16.7) | 32.91 (18.6) | < 0.001a | 27.03 (16.7) | 24.61 (15.6) | < 0.001a |
| Enrollment in Humana program that may impact adherence, n (%) | 3,230 (10.3) | 1,1350 (10.1) | < 0.001b | 3,800 (9.7) | 5,579 (10.2) | < 0.001b |
a Wilcoxon rank sum test was used for the continuous variables for all the tables.
b Chi-square test was used for the categorical variables for all the tables.
A1c = glycated hemoglobin; CDS = Chronic Disease Score; DCCI = Deyo-Charlson Comorbidity Index; DCSI = Diabetes Complications Severity Index; DPP-4 = dipeptidyl peptidase-4; IQR = interquartile range; OAD = oral antidiabetic drug; PDC = proportion of days covered; SD = standard deviation.