Table 5. Factors Associated with Biologic Use Among Patients Receiving Therapy Indicated for Moderate to Severe Psoriasisa.
| Characteristic | Status | Unadjusted Odds Ratio (95% Confidence Interval) | Adjusted Odds Ratiob (95% Confidence Interval) | Adjusted Rate, % (95% Confidence Interval) |
|---|---|---|---|---|
| Factors Associated with Higher Odds of Biologic Use | ||||
| Dermatology Provider Density | 3.4 per 100,000 (sample mean) | 1.01 (0.98-1.04) | 1.08 (1.01-1.16) | 37.4 (35.3-39.5) |
| 4.4 per 100,000 (one unit increase) | 38.9 (36.4-41.3) | |||
| Residence in Urban County | No | Reference | 31.5 (26.9-36.1) | |
| Yes | 1.22 (0.94-1.60) | 1.54 (1.13-2.11) | 39.2 (36.8-41.7) | |
| Ankylosing Spondylitis | No | Reference | 37.3 (35.2-39.4) | |
| Yes | 2.52 (1.24-5.09) | 2.26 (1.13-4.53) | 52.5 (39.2-65.9) | |
| Inflammatory Bowel Disease | No | Reference | 37.3 (35.2-39.4) | |
| Yes | 7.46 (2.29-24.3) | 8.11 (1.91–34.5) | 75.6 (53.5-97.7) | |
| Psoriatic Arthritis | No | Reference | 30.7 (28.2-33.2) | |
| Yes | 3.71 (2.85-4.83) | 3.79 (2.74–5.24) | 57.3 (51.8-62.8) | |
| Renal Disease | No | Reference | 36.1 (33.8-38.4) | |
| Yes | 1.45 (1.00-2.11) | 2.03 (1.24–3.35) | 49.5 (40.6-58.5) | |
| Factors Associated with Lower Odds of Biologic Use | ||||
| Primary Care Provider Density | 6.2 per 10,000 (sample mean) | 0.98 (0.94-1.01) | 0.92 (0.86-0.98) | 36.9 (34.8-39.1) |
| 7.2 per 10,000 (one unit increase) | 35.8 (33.4-38.1) | |||
| Part D Low-Income Subsidy | Full | Reference | 50.6 (44.9-56.3) | |
| None | 0.36 (0.29-0.45) | 0.30 (0.19–0.46) | 27.2 (23.5-30.9) | |
| Race | White | Reference | 38.2 (35.9-40.5) | |
| Black | 0.55 (0.31-0.99) | 0.31 (0.16–0.60) | 19.8 (11.4-28.1) | |
| Cancer | No | Reference | 38.2 (35.9-40.5) | |
| Yes | 0.38 (0.26-0.56) | 0.47 (0.31–0.72) | 25.7 (19.4-31.9) | |
| Dementia | No | Reference | 37.7 (35.5-39.8) | |
| Yes | 0.41 (0.13-1.28) | 0.26 (0.07-0.97) | 17.2 (2.1-32.3) | |
Moderate to severe psoriasis is identified by receipt of either phototherapy, oral systemic or biologic therapy.
Based on a multivariable logistic regression model including the following covariates: age, sex, race, census region of residence, county-level per-capita income, county-level poverty rate, county-level urban versus rural status, county-level low educational level, density of dermatologists and adult primary care providers per number of residents in the patient's county of residence, part D plan type, low-income subsidy status, number of non-psoriasis medications, RxHCC score, and comorbid disease status including all components of the Charlson comorbidity index, autoimmune diseases for which biologic therapies are indicated, cardiovascular risk factors, and aggregate of atherosclerotic outcomes.