To the Editor
Racial/ethnic differences in general healthcare utilization exist in the U.S.1 Little is known about healthcare utilization among racial/ethnic groups for skin diseases including for psoriasis, the most prevalent immune-mediated disease.2 Thus, we aimed to evaluate healthcare utilization for psoriasis by race/ethnicity using population-based data derived from the Medical Expenditure Panel Surveys (MEPS), the most complete source of information on healthcare utilization, cost, and health insurance coverage in the U.S.3 This study was granted exempt status by the University of Pennsylvania Institutional Review Board.
We conducted a cohort study using MEPS data pooled from years 2001–2013. The study population was limited to subjects who reported having psoriasis. The primary explanatory variable was race/ethnicity categorized as non-Hispanic white (reference), Hispanic white, and non-Hispanic minority (black, Asian, Native Hawaiian, Pacific Islander, Native American, Alaskan Native, and multiracial); Hispanic non-whites were excluded due to small numbers. Healthcare utilization outcomes included number of ambulatory visits (with any provider), number of prescriptions, and any ambulatory dermatology visit for psoriasis. Additional characteristics of interest included age, sex, the presence of a spouse in the household, census region of residence, highest level of education, health insurance type, household income, medical comorbidity, systemic psoriasis treatment, duration of psoriasis follow-up, and survey year. Multivariable regression was performed to assess the independent association between race/ethnicity and each healthcare utilization outcome. All analyses accounted for the complex survey design and population-based weights.
A total of 842 respondents reported having psoriasis, corresponding to over 1.6 million individuals with self-reported psoriasis in the U.S. Baseline characteristics of the study population are summarized in Table I. In adjusted analyses, non-Hispanic racial minorities reported fewer ambulatory visits for psoriasis than non-Hispanic whites (incidence rate ratio 0.54; 95% CI 0.38–0.77; Table II). This relative difference equates to an absolute difference of 1.24 (95% CI 0.62–1.85) fewer visits per person per year and a total of over 3 million fewer visits per year among non-Hispanic racial minorities versus non-Hispanic whites with psoriasis. Non-Hispanic minorities were also less likely to report having seen a dermatologist for psoriasis than non-Hispanic whites (odds ratio 0.59; 95% CI 0.36–0.95; Table II). In contrast, the number of prescriptions obtained for psoriasis was not significantly different among racial/ethnic groups (Table III). All findings were robust to a sensitivity analysis that excluded individuals with reported oral systemic or biologic use (7.1% of the study population).
Table I.
Baseline characteristics by race/ethnicity
| Medical Expenditures Panel Surveys, 2001–2013, unweighted N = 842, weighted N = 1,676,778 | ||||
|---|---|---|---|---|
|
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| Race/Ethnicity | ||||
|
|
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| Non-Hispanic white 82.8% Weighted % (95% CI) |
Hispanic white 7.5% Weighted % (95% CI) |
Non-Hispanic minoritya 9.7% Weighted % (95% CI) |
P-valueb | |
| Age (years) | ||||
| 0–17 | 7.1 (5.2–9.7) | 11.5 (6.4–19.9) | 14.8 (8.6–24.4) | |
| 18–40 | 27.0 (22.9–31.5) | 47.1 (35.3–59.3) | 31.0 (22.0–41.8) | |
| 41–64 | 42.9 (38.4–47.4) | 34.4 (23.9–46.7) | 40.9 (31.5–51.1) | |
| 65+ | 23.0 (19.6–26.8) | 7.0 (3.3–14.1) | 13.2 (7.6–22.0) | <0.001 |
| Female | 50.8 (46.7–54.8) | 39.9 (29.6–51.1) | 60.3 (50.5–69.3) | 0.03 |
| Spouse in household | 57.9 (53.6–62.1) | 30.9 (21.7–41.9) | 44.9 (35.7–54.4) | <0.001 |
| Census region | ||||
| Northeast | 21.1 (17.2–25.6) | 15.4 (8.4–26.4) | 10.3 (5.8–17.7) | |
| Midwest | 24.5 (20.8–28.5) | 10.5 (4.6–22.4) | 13.4 (7.9–21.7) | |
| South | 34.4 (29.9–39.1) | 33.7 (20.7–49.8) | 53.1 (43.8–62.2) | |
| West | 20.1 (16.3–24.4) | 40.4 (27.5–54.8) | 23.2 (16.1–32.2) | <0.001 |
| Education level | ||||
| Less than high school diploma | 14.4 (11.6–17.7) | 31.5 (21.2–43.9) | 23.7 (17.2–31.8) | |
| HS diploma, vocational school | 52.6 (47.8–57.4) | 52.6 (40.6–64.3) | 45.1 (36.2–54.4) | |
| Bachelor's degree | 21.5 (17.7–24.9) | 12.1 (6.1–22.6) | 18.5 (10.9–29.8) | |
| Masters/Doctorate | 11.5 (8.7–15.1) | 3.9 (1.7–8.7) | 12.6 (6.9–22.0) | 0.003 |
| Health insurance type | ||||
| Any private | 80.5 (76.7–83.8) | 62.2 (50.5–72.7) | 78.2 (67.9–85.9) | |
| Public only | 14.2 (11.5–17.3) | 27.7 (18.8–38.7) | 19.0 (11.8–29.0) | |
| Uninsured | 5.3 (3.7–7.7) | 10.1 (5.4–18.1) | 2.8 (1.0–7.8) | 0.004 |
| Income level | ||||
| Low (<200% poverty line) | 21.0 (17.7–24.7) | 29.9 (20.2–41.8) | 34.7 (25.4–45.4) | |
| Middle (200–400% poverty line) | 27.2 (23.6–31.2) | 27.7 (19.3–38.2) | 34.7 (25.3–45.5) | |
| High (>400% poverty line) | 51.8 (47.2–56.4) | 42.4 (30.3–55.4) | 30.6 (22.7–39.8) | 0.003 |
| Comorbidity score | ||||
| 0 points | 65.9 (61.8–69.7) | 71.0 (59.9–80.0) | 60.9 (50.3–70.6) | |
| 1 point | 10.7 (8.3–13.7) | 8.9 (4.1–18.1) | 16.3 (10.0–25.4) | |
| 2 points | 13.2 (10.4–16.6) | 12.2 (5.8–23.8) | 8.4 (4.6–14.9) | |
| 3+ points | 10.2 (7.7–13.5) | 8.0 (3.4–17.4) | 14.4 (8.5–23.4) | 0.38 |
| Duration of psoriasis follow-up | ||||
| One round | 10.4 (7.9–13.6) | 8.1 (3.5–17.7) | 11.9 (6.4–21.1) | |
| Two rounds | 11.4 (8.7–14.8) | 7.8 (4.1–14.4) | 16.3 (10.1–25.3) | |
| Three rounds | 16.2 (13.1–19.9) | 22.5 (13.4–35.3) | 16.6 (10.0–26.4) | |
| Four rounds | 20.7 (17.3–24.5) | 29.5 (20.3–40.7) | 26.3 (17.5–37.5) | |
| Five rounds | 41.3 (36.6–46.3) | 32.1 (21.1–45.5) | 28.9 (21.6–37.4) | 0.21 |
| Panel number | ||||
| Panels 6–9 | 29.6 (25.5–34.0) | 25.3 (15.6–38.3) | 32.1 (24.1–41.4) | |
| Panels 10–13 | 33.5 (29.1–38.3) | 24.6 (15.5–36.6) | 32.2 (22.8–43.5) | |
| Panels 14–17 | 36.9 (32.2–41.9) | 50.1 (37.2–63.0) | 35.6 (25.6–47.1) | 0.33 |
Non-Hispanic minority includes black, Asian/Native Hawaiian/Pacific Islander, American Indian/Alaskan Native, and multiracial.
P-values were calculated using the Rao-Scott design-based chi-squared test.
Table II.
Ambulatory visit outcomes for psoriasis by race/ethnicity: number of all ambulatory visits (A) and any dermatology visit (B)
| A. Number of all ambulatory visits for psoriasis | |||
|---|---|---|---|
| Medical Expenditures Panel Surveys, 2001–2013, unweighted N = 842, weighted N = 1,676,778 | |||
|
| |||
| Mean per year (95% CI) |
Unadjusted IRR (95% CI) |
Adjusted IRRa (95% CI) |
|
| Overall | 2.51 (2.00–3.02) | - | - |
| Race/ethnicity | |||
| Non-Hispanic white | 2.69 (2.09–3.28) | Reference | Reference |
| Hispanic white | 1.87 (1.18–2.56) | 0.76 (0.46–1.25) | 0.78 (0.49–1.24) |
| Non-Hispanic minorityb | 1.30 (0.91–1.70) | 0.43 (0.29–0.65) | 0.54 (0.38–0.77) |
| B. Any ambulatory dermatology visit for psoriasis | |||
|---|---|---|---|
| Medical Expenditures Panel Surveys, 2002–2013, unweighted N = 744, weighted N = 1,547,003 | |||
|
| |||
| Yes, Weighted % (95% CI) |
Unadjusted OR (95% CI) |
Adjusted ORc (95% CI) |
|
| Overall | 49.2 (45.0–53.4) | - | - |
| Race/ethnicity | |||
| Non-Hispanic white | 50.8 (45.9–55.6) | Reference | Reference |
| Hispanic white | 46.7 (32.7–61.2) | 0.85 (0.45–1.62) | 1.03 (0.53–2.00) |
| Non-Hispanic minorityb | 38.3 (28.8–48.9) | 0.60 (0.38–0.95) | 0.59 (0.36–0.95) |
Adjusted incidence rate ratios (IRR) and 95% confidence intervals (CI) were calculated using negative binomial regression adjusting for age, sex, household income, census region, marital status (spouse in the household), education level, and health insurance type, accounting for the duration of psoriasis follow-up.
Non-Hispanic minority includes black, Asian/Native Hawaiian/Pacific Islander, American Indian/Alaskan Native, and multiracial.
Adjusted odds ratios (OR) and 95% confidence intervals (CI) were calculated using logistic regression, adjusting for age, sex, household income, census region, marital status (spouse in the household), education level, and health insurance type.
Table III.
Number of prescriptions obtained for psoriasis by race/ethnicity
| Medical Expenditures Panel Surveys, 2001–2013, unweighted N = 842, weighted N = 1,676,778 | |||
|---|---|---|---|
|
| |||
| Mean per year (95% CI) |
Unadjusted IRR (95% CI) |
Adjusted IRRa (95% CI)* |
|
| Overall | 2.03 (1.85–2.22) | - | - |
| Race/ethnicity | |||
| Non-Hispanic white | 2.07 (1.86–2.28) | Reference | Reference |
| Hispanic white | 1.81 (1.43–2.18) | 0.84 (0.63–1.13) | 0.89 (0.64–1.24) |
| Non-Hispanic minorityb | 1.86 (1.43–2.28) | 0.88 (0.65–1.21) | 0.90 (0.68–1.19) |
Adjusted incidence rate ratios (IRR) and 95% confidence interval (95% CI) were calculated using negative binomial regression adjusting for age, sex, poverty level, census region, marital status (spouse in household), education level, and health insurance type, accounting for the duration of psoriasis follow-up
Non-Hispanic minority includes black, Asian/Native Hawaiian/Pacific Islander, American Indian/Alaskan Native, and multi-racial.
Study limitations include: self-reported information which may be subject to error, small sample size precluding analysis of certain minority populations and evaluation of systemic therapies as an outcome, and lack of direct information on psoriasis severity.
Our new identification of disparities in ambulatory healthcare utilization for psoriasis among non-Hispanic minorities is particularly notable in light of prior data suggesting that racial/ethnic minorities have more severe psoriasis4,5 and poorer quality of life5 due to their skin disease compared with whites. Additional studies to understand why differences in healthcare utilization exist are necessary to achieve equitable care for all patients with psoriasis.
Acknowledgments
Funding/Support:
JT is supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases grant K23-AR068433. JMG is supported by NIAMS grant K24-AR064310.
In the previous 12 months, Dr. Gelfand served as a consultant for Coherus (DSMB), Dermira, Janssen Biologics, Merck (DSMB), Novartis Corp, Regeneron, Sanofi, and Pfizer Inc., receiving honoraria; and receives research grants (to the Trustees of the University of Pennsylvania) from Abbvie, Janssen, Novartis Corp, Regeneron, Sanofi, Celgene, and Pfizer Inc.; and received payment for continuing medical education work related to psoriasis that was supported indirectly by Eli Lilly and Abbvie. Dr. Gelfand is a co-patent holder of resiquimod for treatment of cutaneous T cell lymphoma. Dr. Takeshita has received a research grant from Pfizer Inc (to the Trustees of the University of Pennsylvania) and payment for continuing medical education work related to psoriasis that was supported indirectly by Eli Lilly.
Footnotes
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IRB Statement: The study was granted exempt status by the University of Pennsylvania Institutional Review Board.
References
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