Background
Methods
Study population and inclusion criteria
Patient identification
Condition | ICD-9 diagnosis codes | ICD-9 procedure codes | HCPCS codes | CPT codes |
---|---|---|---|---|
Valvular disease | 394.x–397.x, 398.9x,093.2x,391.1x, 398.90,424.xx, 746.0x-46.7x,996.02, 996.71 | 35.0x-5.2x, 35.31,35.32, 35.33,35.95-35.97, 35.99 | - | 33400-33496, 33600, 33602, 33660, 33665, 33670, 33684, 92986-92990 |
Hyperthyroidism | 242 | - | - | - |
Study measures of interest
Statistical analysis
Results
Descriptive analysis results
Characteristics | All patient cohorts | OAC-naïve cohorts | ||||||||
---|---|---|---|---|---|---|---|---|---|---|
Dabigatran (n = 3,019) | Warfarin (n = 17,301) | P-value | Dabigatran (n = 815) | Warfarin (n = 1,590) | P-value | |||||
N/mean | %/SD | N/mean | %/SD | N/mean | %/SD | N/mean | %/SD | |||
Patient demographic variables
| ||||||||||
Age (years), n,%
| ||||||||||
18-44 | 57 | 1.9 | 147 | 0.8 | <.0001 | 30 | 3.7 | 22 | 1.4 | <.0001 |
45-54 | 297 | 9.8 | 897 | 5.2 | 108 | 13.3 | 132 | 8.3 | ||
55-64 | 1,040 | 34.4 | 3,299 | 19.1 | 313 | 38.4 | 363 | 22.8 | ||
65-74 | 777 | 25.7 | 4,213 | 24.4 | 191 | 23.4 | 375 | 23.6 | ||
75-84 | 619 | 20.5 | 5,969 | 34.5 | 124 | 15.2 | 486 | 30.6 | ||
85+ | 229 | 7.6 | 2,776 | 16.0 | 49 | 6.0 | 212 | 13.3 | ||
Age, mean, SD
| 67 | ±11.4 | 73 | ±11.4 | <.0001 | 65 | ±11.9 | 71 | ±12.1 | <.0001 |
Female
| 878 | 29.1 | 6,775 | 39.2 | <.0001 | 224 | 27.5 | 563 | 35.4 | <.0001 |
Health plan and healthcare provider variables
| ||||||||||
Insurance plan, n,%
| ||||||||||
Preferred provider organization | 2,047 | 67.8 | 8,522 | 49.3 | <.0001 | 556 | 68.2 | 841 | 52.9 | <.0001 |
Health maintenance organization | 396 | 13.1 | 4,136 | 23.9 | 108 | 13.3 | 308 | 19.4 | ||
Other | 576 | 19.1 | 4,643 | 26.8 | 151 | 18.5 | 441 | 27.7 | ||
Health plan region, n,%
| ||||||||||
Midwest | 648 | 21.5 | 6,333 | 36.6 | <.0001 | 185 | 22.7 | 714 | 44.9 | <.0001 |
Northeast | 720 | 23.8 | 4,257 | 24.6 | 175 | 21.5 | 300 | 18.9 | ||
West | 966 | 32.0 | 3,962 | 22.9 | 262 | 32.1 | 356 | 22.4 | ||
South | 685 | 22.7 | 2,749 | 15.9 | 193 | 23.7 | 220 | 13.8 | ||
Physician specialty, n,%
| ||||||||||
Cardiology | 1,541 | 51.0 | 5,234 | 30.3 | <.0001 | 418 | 51.3 | 520 | 32.7 | <.0001 |
Primary care/internal medicine | 424 | 14.1 | 6,132 | 35.5 | 75 | 9.2 | 418 | 26.3 | ||
Other | 1,054 | 34.9 | 5,935 | 34.2 | 322 | 39.5 | 652 | 41.0 | ||
Patient out of pocket pharmacy costs during the pre-index period
| $1,012 | $1,585 | $952 | $1,050 | 0.0080 | $870 | ±$2,135 | $655 | ±$735 | 0.0003 |
Characteristics | All patient cohorts | OAC-naïve cohorts | ||||||||
---|---|---|---|---|---|---|---|---|---|---|
Dabigatran (n = 3,019) | Warfarin (n = 17,301) | P-value | Dabigatran (n = 815) | Warfarin (n = 1,590) | P-value | |||||
N/mean | %/SD | N/mean | %/SD | N/mean | %/SD | N/mean | %/SD | |||
Summary comorbidity/severity scores
| ||||||||||
CHADS2, mean, SD | 1.9 | ±1.3 | 2.2 | ±1.3 | <.0001 | 1.7 | ±1.4 | 2.2 | ±1.4 | <.0001 |
ATRIA, mean, SD | 2.3 | ±2.1 | 3.0 | ±2.3 | <.0001 | 2.0 | ±2.0 | 3.1 | ±2.6 | <.0001 |
Elixhauser (ECI), mean, SD | 4.0 | ±2.2 | 4.3 | ±2.3 | <.0001 | 3.7 | ±2.1 | 4.5 | ±2.6 | <.0001 |
Selected pre-index comorbidities, n,%
| ||||||||||
Any ischemic stroke | 497 | 16.5 | 2,567 | 14.8 | 0.0213 | 127 | 15.6 | 259 | 16.3 | 0.6550 |
Any TIAs | 169 | 5.6 | 789 | 4.6 | 0.0131 | 46 | 5.6 | 90 | 5.7 | 0.9870 |
Heart failure | 603 | 20.0 | 4,592 | 26.5 | <.0001 | 136 | 16.7 | 445 | 28.0 | <.0001 |
Hypertension | 2,394 | 79.3 | 14,202 | 82.1 | 0.0003 | 626 | 76.8 | 1,288 | 81.0 | 0.0157 |
Diabetes mellitus | 895 | 29.6 | 5,683 | 32.8 | 0.0005 | 207 | 25.4 | 508 | 31.9 | 0.0009 |
Chronic kidney disease (stages II-V) | 172 | 5.7 | 1,265 | 7.3 | 0.0014 | 45 | 5.5 | 154 | 9.7 | 0.0005 |
Heart rate and heart rhythm control procedures* | 155 | 5.1 | 436 | 2.5 | <.0001 | 44 | 5.4 | 66 | 4.1 | 0.1656 |
Pre-index use of selected medications
| ||||||||||
Use of warfarin, n,% | 2,204 | 73.0 | 15,711 | 90.8 | <.0001 | 0 | 0.0 | 0 | 0.0 | NA |
≥1 PT tests, n,% | 2,111 | 69.9 | 13,575 | 78.5 | <.0001 | NA | NA | NA | NA | NA |
Parenteral anticoagulants, n,% | 231 | 7.7 | 974 | 5.6 | <.0001 | 13 | 1.6 | 59 | 3.7 | 0.0040 |
Any platelet inhibitor | 648 | 21.5 | 2,768 | 16.0 | <.0001 | 225 | 27.6 | 341 | 21.4 | 0.0007 |
Prescription NSAIDs | 456 | 15.1 | 1,791 | 10.4 | <.0001 | 145 | 17.8 | 190 | 11.9 | <.0001 |
Any rate control medication | 2,475 | 82.0 | 13,916 | 80.4 | 0.0472 | 614 | 75.3 | 1,119 | 70.04 | 0.0103 |
Any rhythm control medication, n,% | 948 | 31.4 | 3,238 | 18.7 | <.0001 | 286 | 35.1 | 353 | 22.2 | <.0001 |
Any rate or rhythm control medications | 2,562 | 84.86 | 14,223 | 82.21 | 0.0004 | 654 | 80.3 | 1,164 | 73.2 | 0.0001 |
Any dyspepsia medication, n,% | 749 | 24.8 | 4,122 | 23.8 | 0.2424 | 173 | 21.3 | 362 | 22.8 | 0.3900 |
Proton-pump inhibitor (PPI) | 689 | 22.8 | 3,701 | 21.4 | 0.0781 | 159 | 19.5 | 320 | 20.1 | 0.7201 |
Histamine type-2 receptor antagonist (H2RA) | 100 | 3.3 | 583 | 3.4 | 0.8717 | 26 | 3.2 | 55 | 3.5 | 0.7293 |
Multivariable LR results
Independent variables | All-patient cohort† | OAC-naïve cohort# | ||||||
---|---|---|---|---|---|---|---|---|
Odds ratio | 95% confidence limits | P-value | Odds ratio | 95% confidence limits | P-value | |||
Intercept | -1.34 | <.0001 | -1.26 | <.0001 | ||||
Female (reference = male) | 0.87 | 0.79 | 0.96 | 0.0035 | 1.02 | 0.83 | 1.26 | 0.8362 |
55-64 age group (reference = 18–54) | 1.00 | 0.86 | 1.16 | 0.9517 | 0.90 | 0.68 | 1.21 | 0.4865 |
65-74 age group | 0.64 | 0.55 | 0.75 | <.0001 | 0.59 | 0.43 | 0.81 | 0.0010 |
75-84 age group | 0.44 | 0.37 | 0.53 | <.0001 | 0.40 | 0.28 | 0.58 | <.0001 |
85+ age group | 0.39 | 0.31 | 0.48 | <.0001 | 0.42 | 0.26 | 0.66 | 0.0002 |
Midwest region indicator (reference = west) | 0.55 | 0.49 | 0.62 | <.0001 | 0.43 | 0.34 | 0.56 | <.0001 |
Northeast region indicator | 0.90 | 0.80 | 1.01 | 0.0816 | 0.93 | 0.70 | 1.23 | 0.6125 |
South region indicator | 1.05 | 0.93 | 1.19 | 0.4389 | 1.12 | 0.85 | 1.49 | 0.4282 |
PPO insurance indicator (reference = HMO) | 1.68 | 1.48 | 1.92 | <.0001 | 1.47 | 1.10 | 1.96 | 0.0089 |
Other insurance type indicator | 1.31 | 1.13 | 1.52 | 0.0003 | 1.20 | 0.87 | 1.66 | 0.2770 |
Total ATRIA score | 0.98 | 0.95 | 1.00 | 0.0477 | 0.91 | 0.86 | 0.96 | 0.0005 |
Pre-index heart failure | 0.78 | 0.70 | 0.87 | <.0001 | 0.76 | 0.59 | 0.97 | 0.0253 |
Pre-index hypertension | 1.16 | 1.04 | 1.30 | 0.0083 | 1.32 | 1.04 | 1.69 | 0.0246 |
Pre-index warfarin | 0.34 | 0.31 | 0.38 | <.0001 | ||||
Pre-index any anti-platelet/NSAIDS fill | 1.15 | 1.03 | 1.28 | 0.0097 | ||||
Prior use of any dyspepsia medication | 1.13 | 1.03 | 1.25 | 0.0146 | ||||
Cardiology specialty of index OAC prescriber indicator (reference = PCP/family/internal medicine) | 3.12 | 2.77 | 3.51 | <.0001 | 3.59 | 2.68 | 4.81 | <.0001 |
Other specialty of index OAC prescriber | 1.94 | 1.72 | 2.20 | <.0001 | 2.22 | 1.65 | 2.97 | <.0001 |
Pre-index PT test use | 0.70 | 0.64 | 0.78 | <.0001 | ||||
Pre-index any heart rate/rhythm control medication fill | 1.19 | 1.06 | 1.34 | 0.0037 | ||||
Pre-index any Afib related procedure | 1.53 | 1.38 | 1.71 | <.0001 | ||||
Pre-index ischemic stroke | 1.34 | 1.18 | 1.53 | <.0001 | 1.42 | 1.06 | 1.90 | 0.0183 |
Pre-index TIA | 1.24 | 1.02 | 1.51 | 0.0281 | ||||
Total patient out of pocket pharmacy costs (per $1 K) during the pre-index period | 1.04 | 1.01 | 1.08 | 0.0251 | 1.32 | 1.17 | 1.48 | <.0001 |