Table 4.
Coding of covariates in baseline period—all included when studying fracture risk
| Variable | Definition | Coding |
|---|---|---|
| Medicare enrolment information at time of index prescription | ||
| Age | Age in years | Categorical, groupings: 65–69, 70–74, 75–79, 80–84, 85–89, and 90 or more years |
| Race | Caucasian race | Dichotomous (yes/no) |
| Medicare claims within 365 days prior to index osteoporosis drug prescription | ||
| Hospitalization within prior year | Any | Dichotomous (yes/no) |
| Comorbidity score | Charlson comorbidity score (17, 18) | Ordinal (quartiles, 3 dummies) |
| Osteoporosis related | ||
| Osteoporosis | ICD-9-CM: 733.0x | Dichotomous (yes/no) |
| Kyphosis | ICD-9-CM: 737.1x, 737.41, 737.3x | Dichotomous (yes/no) |
| Prior fracture—vertebral | Vertebral (ICD-9-CM: 733.13, 805.xx) | Dichotomous (yes/no) |
| Prior fracture—non-vertebral | Hip (ICD-9-CM: 820.xx, 733.14), humerus (ICD-9-CM: 812.xx, 733.11), and/or radius/ulna (ICD-9-CM: 813.xx, 733.12) | Dichotomous (yes/no) |
| Prior fracture—other | Any fracture (ICD-9-CM: 733.1x, 800.xx-829.xx) other than vertebral / non-vertebral defined above | Dichotomous (yes/no) |
| Comorbidities | ||
| Alzheimer’s/other dementia | ICD-9-CM: 290.xx, 294.xx, 330.xx, 331.xx | Dichotomous (yes/no) |
| Asthma/chronic obstructive pulmonary disease | ICD-9-CM: 493.xx, 490, 491.xx, 492.xx, 494.xx, 496.xx, 506.4x | Dichotomous (yes/no) |
| Cataracts | ICD-9-CM: 366.xx | Dichotomous (yes/no) |
| Crohn’s/gastroenteritis | ICD-9-CM: 555.xx, 556.xx, 558.xx | Dichotomous (yes/no) |
| Depression | ICD-9-CM: 293.83, 296.2x. 296.3x, 298.0x, 300.4x, 309.0x, 309.1x, 309.28, 311.xx | Dichotomous (yes/no) |
| Diabetes mellitus | ICD-9-CM: 1 hospitalization discharge of 250.xx or 2 outpatient claims with 250.xx | Dichotomous (yes/no) |
| Falls history, syncope, or gait abnormality | ICD-9-CM: E885, E885.9x, E888.xx, 780.2x, 458.0x, 781.2x, 782.3x | Dichotomous (yes/no) |
| Hyperthyroidism | ICD-9-CM: 242.0x-242.9x | Dichotomous (yes/no) |
| Hyperparathyroidism | ICD-9-CM: 252.0x | Dichotomous (yes/no) |
| Ischemic stroke | ICD-9-CM: 434.xx, 436.xx | Dichotomous (yes/no) |
| Liver disease | ICD-9-CM: 571.4x, 571.6x, 571.8x, 571.9x, 573.xx, 070.xx | Dichotomous (yes/no) |
| Malignant neoplasm | ICD-9-CM: 140.xx-208.xx | Dichotomous (yes/no) |
| Overweight or obese | ICD-9-CM: 278, 278.0x | Dichotomous (yes/no) |
| Parkinson’s | ICD-9-CM: 332.xx, 333.0x or use of antiparkinsonian drug | Dichotomous (yes/no) |
| Renal disease | ICD-9-CM: 250.4x, 403.xx, 404.02, 404.03, 404.12, 404.13, 404.92, 404.93 | Dichotomous (yes/no) |
| Rheumatoid arthritis | ICD-9-CM: 714.xx | Dichotomous (yes/no) |
| Pharmacy claims within 365 days prior to index osteoporosis drug prescription | ||
| Number of generics | Count | Ordinal (quintiles, 4 dummies) |
| Anti-epileptic | Any pharmacy claim | Dichotomous (yes/no) |
| Beta-blocker | Any pharmacy claim | Dichotomous (yes/no) |
| Benzodiazepines | Any pharmacy claim | Dichotomous (yes/no) |
| Gastroprotective | Any pharmacy claim | Dichotomous (yes/no) |
| Glucocorticoids | Any pharmacy claim | Dichotomous (yes/no) |
| Hormone therapy | Any pharmacy claim | Dichotomous (yes/no) |
| Selective Cox-2 inhibitor | Any pharmacy claim | Dichotomous (yes/no) |
| Other nonsteroidal anti-inflammatory drug | Any pharmacy claim | Dichotomous (yes/no) |
| Selective serotonin reuptake inhibitors (SSRI) | Any pharmacy claim | Dichotomous (yes/no) |
| Non-SSRI antipsychotic | Any pharmacy claim | Dichotomous (yes/no) |
| Statin therapy | Any pharmacy claim | Dichotomous (yes/no) |
| Thiazide diuretic | Any pharmacy claim | Dichotomous (yes/no) |
| Thyroid drugs | Any pharmacy claim | Dichotomous (yes/no) |
| Miscellaneous sleep/hypnotic/barbiturates | Any pharmacy claim | Dichotomous (yes/no) |