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. Author manuscript; available in PMC: 2015 Oct 1.
Published in final edited form as: JAMA Ophthalmol. 2014 Oct 1;132(10):1199–1208. doi: 10.1001/jamaophthalmol.2014.1720

Table 1. Characteristics of Study Population.

Chloroquine / Hydroxychloroquine Use**
Yes No Overall p-value
Total 6,339 (35.1) 11,712 (64.9) 18,051 (100.0)
Rheumatologic Condition (Nmiss = 0) SLE 1,768 (27.9) 1,617 (13.8) 3,385 (18.8) < 0.0001
Rheumatoid Arthritis 3,570 (56.3) 9,532 (81.4) 13,102 (72.6)
Both 1,001 (15.8) 563 (4.8) 1,564 (8.7)
Sex (Nmiss = 0) Male 1,004 (15.8) 2,933 (25.0) 3,937 (21.8) < 0.0001
Female 5,335 (84.2) 8,779 (75.0) 14,114 (78.2)
Race (Nmiss = 1,459) White 4,910 (84.3) 8,940 (83.0) 13,850 (83.5) 0.003
Black 325 (5.6) 558 (5.2) 883 (5.3)
Latino 406 (7.0) 936 (8.7) 1,342 (8.1)
Asian 131 (2.2) 233 (2.2) 364 (2.2)
Other 55 (0.9) 98 (0.9) 153 (0.9)
Education (Nmiss = 509) Less than High School 86 (1.4) 174 (1.5) 260 (1.5) 0.0118
High School Diploma 2,057 (33.3) 3,906 (34.4) 5,963 (34.0)
Some College 2,500 (40.5) 4,721 (41.5) 7,221 (41.2)
College Diploma 1,523 (24.7) 2,549 (22.4) 4,072 (23.2)
Advanced Degree 12 (0.2) 14 (0.1) 26 (0.1)
Household Income (Nmiss = 1,126) < $30,000 468 (7.9) 944 (8.6) 1,412 (8.3) 0.0230
$30,000 – $60,000 1,966 (33.1) 3,796 (34.6) 5,762 (34.0)
$60,000 – $100,000 2,139 (36.0) 3,912 (35.6) 6,051 (35.8)
$100,000 – $125,000 759 (12.8) 1,291 (11.8) 2,050 (12.1)
> $125,000 613 (10.3) 1037 (9.4) 1,650 (9.7)
Medication Use (Nmiss = 0) CQ use only 36 (0.6) 0 (0.0) 36 (0.2) < 0.0001
HCQ use only 6,248 (98.6) 0 (0.0) 6,248 (34.6)
Both medications 55 (0.9) 0 (0.0) 55 (0.3)
Neither 0 (0.0) 11,712 (100.0) 11,712 (64.9)
Medication Use Duration (Nmiss = 0) No Medication Use 0 (0.0) 11,712 (100.0) 11,712 (64.9) < 0.0001
< 12 Months 2,150 (33.9) 0 (0.0) 2,150 (33.9)
12-23 Months 914 (14.4) 0 (0.0) 914 (14.4)
24-47 Months 1866 (29.4) 0 (0.0) 1866 (29.4)
≥ 48 Months 1409 (22.2) 0 (0.0) 1409 (22.2)
Eye Visits (Nmiss = 0) No eye visits 906 (14.3) 3,308 (28.2) 4,214 (23.3) < 0.0001
One Year 1,135 (17.9) 2,811 (24.0) 3,946 (21.9)
Two years 1,041 (16.4) 1,774 (15.1) 2,815 (15.6)
Three years 906 (14.3) 1,494 (12.8) 2,400 (13.3)
Four years 1,034 (16.3) 1,133 (9.7) 2,167 (12.0)
Five years 1,317 (20.8) 1,192 (10.2) 2,509 (13.9)
Depression No 5,360 (84.6) 10,009 (85.5) 15,369 (85.1) 0.1
Yes 979 (15.4) 1,703 (14.5) 2,682 (14.9)
Hypertension None 2,241 (35.4) 3,250 (27.7) 5,491 (30.4) < 0.0001
Uncomplicated 3,121 (49.2) 6,238 (53.3) 9,359 (51.8)
Complicated 977 (15.4) 2,224 (19.0) 3,201 (17.7)
Diabetes mellitus None 4,782 (75.4) 7,683 (65.6) 12,465 (69.1) < 0.0001
Uncomplicated 1,079 (17.0) 2,848 (24.3) 3,927 (21.8)
Complicated 478 (7.5) 1,181 (10.1) 1,659 (9.2)
Age at Enrollment (years) 49.67 (11.43) 52.70 (12.33) 51.63 (12.11) < 0.0001Δ
Time in Plan (years) 7.90 (1.82) 8.08 (1.82) 8.01 (1.82) < 0.0001Δ
Medication Use (days) 824.10 (610.20) ----- 824.10 (610.20) -----
Eye Visits 5.06 (5.40) 3.82 (6.17) 4.25 (5.94) < 0.0001Δ
Charlson Comorbidity Index* 3.78 (2.92) 4.25 (3.11) 4.08 (3.06) < 0.0001Δ
**

Chloroquine/hydroxychloroquine use in the first five years of enrollment. Complicated diabetes=diabetes with end organ damage, complicated hypertension=hypertension with end organ damage, SLE = Systemic Lupus Erythematosis, CQ = chloroquine; HCQ = hydroxychloroquine

*

Excludes diabetes.

Only evaluated for the 6,339 individuals taking medication.

Chi-square test.

Δ

Two-sample t-test. Miss=Missing.