Table 3.
Results of Cox proportional hazards analysis of association between baseline factors and reinitiation of therapy among discontinuers
| Characteristic | Person-years (discontinuers who remained off therapy) | Person-years (discontinuers who reinitiated therapy) | Unadjusted hazard ratio (95% CI) | Adjusted hazard ratio (95% CI) |
|---|---|---|---|---|
| Age group, years | ||||
| 55–59 | 12,974 | 4259 | Ref | Ref |
| 60–64 | 10,685 | 3323 | 0.96 (0.93–0.99) | 0.95 (0.92–0.98) |
| 65–69 | 6658 | 1882 | 0.90 (0.86–0.93) | 0.89 (0.86–0.93) |
| 70–74 | 6490 | 1804 | 0.89 (0.85–0.92) | 0.88 (0.85–0.92) |
| 75–79 | 6541 | 1654 | 0.85 (0.82–0.88) | 0.84 (0.81–0.88) |
| 80–89 | 8068 | 1968 | 0.81 (0.78–0.84) | 0.80 (0.77–0.83) |
| ≥90 | 1014 | 226 | 0.76 (0.69–0.83) | 0.76 (0.69–0.84) |
| Number of comorbiditiesa | ||||
| 0 | 1364 | 328 | Ref | Ref |
| 1–5 | 14,523 | 4160 | 1.12 (1.03–1.21) | 1.05 (0.97–1.14) |
| 6–10 | 21,213 | 6205 | 1.16 (1.08–1.26) | 1.07 (0.99–1.16) |
| ≥11 | 15,330 | 4423 | 1.16 (1.07–1.26) | 1.08 (0.99–1.17) |
| Osteoporosis diagnosis | ||||
| No | 37,715 | 10,600 | Ref | Ref |
| Yes | 14,715 | 4516 | 1.07 (1.05–1.10) | 1.07 (1.04–1.10) |
| Any osteoporotic fracture | ||||
| No | 50,319 | 14,579 | Ref | Ref |
| Yes | 2111 | 537 | 0.95 (0.90–1.01) | 1.03 (0.97–1.10) |
| Total number of unique medication classes takenb | ||||
| 0 | 2351 | 646 | Ref | Ref |
| 1–4 | 14,485 | 4013 | 0.98 (0.92–1.04) | 0.98 (0.92–1.03) |
| 5–10 | 21,789 | 6477 | 1.04 (0.98–1.10) | 1.05 (0.99–1.11) |
| ≥11 | 13,805 | 3980 | 1.03 (0.98–1.10) | 1.07 (1.00–1.14) |
| Number of hospitalizations | ||||
| 0 | 44,285 | 13,022 | Ref | Ref |
| ≥1 | 8144 | 2094 | 0.93 (0.90–0.96) | 0.94 (0.90–0.97) |
| Receipt of DXA test | ||||
| No | 22,304 | 6279 | Ref | Ref |
| Yes | 30,125 | 8837 | 1.08 (1.06–1.11) | 1.03 (1.00–1.06) |
Notes:
a
To calculate the total number of comorbidities, a tool provided by the Agency for Healthcare Research and Quality (AHRQ) was used, which clusters patient diagnoses and procedures into a manageable number of clinically meaningful categories.25 This tool was applied to diagnosis and procedure codes in the database;
b
the number of prescriptions filled for unique medication classes was evaluated using the therapeutic class variable in the database.
Abbreviations: CI, confidence interval; DXA, dual-energy X-ray absorptiometry (test of bone mineral density); Ref, reference.