Identifying risk factors for blindness from primary open-angle glaucoma by race: a case–control study

Figures & data

Figure 1 Flowchart of study design.

Notes: From the dataset of 1,454 patients with glaucoma, 80 of the 95 patients who were blind from POAG could be matched (by gender, race, and age within 1 year) with patients with POAG who were not blind. Twenty-four pairs were excluded, leaving 56 pairs (21 pairs of black men, 16 pairs of black women, 9 pairs of white men, and 10 pairs of white women).
Abbreviation: POAG, primary open-angle glaucoma.

Table 1 Demographic characteristics

	Black cases (n=37)	Black controls (n=37)	White cases (n=19)	White controls (n=19)
Mean age in years (SD)	73 (11)	73 (11)	77 (11)	76 (11)
Female sex, n (%)	16 (43)	16 (43)	10 (53)	10 (53)
Follow-up time in years (SD)	8.0 (5.5)	7.6 (6.0)	5.9 (5.2)	7.4 (5.9)

Notes: Cases, patients who have gone blind from primary open-angle glaucoma; controls, patients with primary open-angle glaucoma who are not blind.

Table 2 Clinical variables at presentation by race and case–control status

Variables	Black cases (n=37)	Black controls (n=37)	White cases (n=19)	White controls (n=19)	p-values
					Black cases versus black controls	White cases versus white controls
Visual function metrics
Visual acuity (LogMAR), mean (SD), n
Better eye	0.7 (0.9), 37	0.1 (0.1), 37	0.9 (0.9), 19	0.1 (0.2), 19	<0.001	<0.001
Worse eye	1.8 (1.2), 37	0.8 (1.1), 37	1.9 (1.2), 19	0.5 (0.6), 19	<0.001	0.002
Visual field (MD in dB), mean (SD), n
Better eye	−22 (9), 14	−3 (3), 29	−16 (10), 7	−3 (3), 16	<0.001	0.004
Worse eye	−24 (9), 24	−8 (7), 34	−21 (11), 14	−10 (8), 18	<0.001	0.003
IOP (mmHg), mean (SD), n
Right	21 (10), 36	19 (6), 36	17 (6), 18	20 (6), 19	0.407	0.091
Left	22 (11), 35	20 (8), 36	17 (6), 15	19 (4), 19	0.384	0.497
Cup-to-disc ratio, mean (SD), n
Right	0.9 (0.1), 34	0.7 (0.2), 35	0.9 (0.1), 18	0.7 (0.2), 19	<0.001	0.017
Left	0.9 (0.2), 32	0.8 (0.2), 36	0.8 (0.2), 15	0.7 (0.2), 19	<0.001	0.090
Ocular comorbidities
Diabetic retinopathy, n (%)	4 (11)	2 (5)	1 (5)	0 (0)	0.674	1.000
Macular degeneration, n (%)	0 (0)	0 (0)	2 (11)	2 (11)	1.000	1.000
Uveitis, n (%)	2 (5)	1 (3)	0 (0)	0 (0)	0.674	1.000
Other ocular diagnosis, n (%)	15 (41)	9 (24)	14 (74)	4 (21)	0.214	0.003
Glaucoma treatment history at presentation
No of glaucoma medications, mean (SD)	2.5 (1.4)	1.2 (1.2)	2.7 (1.5)	1.1 (1.1)	<0.001	0.001
History of glaucoma surgery, n (%)	14 (38)	6 (16)	10 (53)	2 (11)	0.089	0.013
Glaucoma laser, n (%)	18 (49)	10 (27)	6 (32)	3 (16)	0.093	0.447
Alpha agonist, n (%)	16 (43)	7 (19)	8 (42)	2 (11)	0.043	0.62
Carbonic anhydrase inhibitor, n (%)	20 (54)	8 (22)	11 (58)	2 (11)	0.008	0.005
Beta-blocker, n (%)	25 (68)	10 (27)	15 (79)	8 (42)	0.001	0.045
Prostaglandin analogue, n (%)	20 (54)	16 (43)	15 (79)	8 (42)	0.486	0.045
Pilocarpine, n (%)	11 (30)	3 (8)	2 (11)	1 (5)	0.035	1.000

Notes: Cases, patients who have gone blind from primary open-angle glaucoma; controls, patients with primary open-angle glaucoma who are not blind. The most common “other ocular diagnoses” were non-blinding corneal diseases and retinal vascular diseases.

Abbreviations: MD, mean deviation; dB, decibels; IOP, intraocular pressure.

Table 3 Treatment course by race and case–control status

Treatment course	Black cases (n=37)	Black controls (n=37)	White cases (n=19)	White controls (n=19)	p-values
					Black cases versus black controls	White cases versus white controls
Glaucoma medications added, mean (SD), n	1.0 (0.8), 4	0.8 (0.7), 17	−0.5 (1.8), 6	0.8 (1.3), 12	0.552	0.055
Glaucoma medications added, excluding patients with surgery or laser, mean (SD), n	1.3 (0.6), 3	0.7 (0.6), 13	−0.5 (1.8), 6	0.8 (1.3), 12	0.131	0.055
Glaucoma surgeries at Duke, mean (SD)
Total surgeries	2.4 (1.6)	1.2 (1.8)	0.9 (0.8)	0.6 (1.0)	0.001	0.139
Trabeculectomies	1.1 (1.0)	0.5 (0.8)	0.4 (0.8)	0.3 (0.6)	0.009	0.708
Tube surgeries	0.9 (1.1)	0.4 (0.7)	0.6 (1.0)	0.2 (0.4)	0.012	0.344
Revisions	0.4 (0.6)	0.3 (0.8)	0.1 (0.3)	0.2 (0.5)	0.428	0.956
Transscleral diode or ECPC	0.4 (0.8)	0.0 (0.2)	0.1 (0.3)	0.0 (0.0)	0.011	0.152
Laser trabeculoplasty, n (%)	5 (14)	9 (24)	3 (16)	2 (11)	0.252	0.934
Other ocular procedure, n (%)	13 (36)	9 (24)	8 (42)	4 (21)	0.315	0.295

Notes: Cases, patients who have gone blind from primary open-angle glaucoma; controls, patients with primary open-angle glaucoma who are not blind.

Abbreviation: ECPC, endocyclophotocoagulation.

Table 4 Adjusteda odds ratio of blindness from POAG by clinical variable and race

Clinical variable	Odds of blindness by variable
	OR (95% CI)
	Black	White
Visual function metrics at presentation
IOP in the right eye (mmHg)	1.04 (0.98–1.10)	0.89 (0.78–1.00)
IOP in the left eye (mmHg)	1.03 (0.97–1.08)	0.95 (0.81–1.10)
Glaucoma treatment history at presentation
No of glaucoma medications	2.1 (1.4–3.2)*	2.9 (1.5–5.9)*
History of prior glaucoma surgeries (versus no prior surgery)	3.2 (1.1–9.5)*	9.3 (1.6–52.6)*
Treatment course over follow-up period
No of glaucoma medications added	2.0 (0.3–12.0)	0.10 (0.01–1.00)
No of glaucoma surgeries at Duke
Total surgeries	1.6 (1.1–2.2)*	1.5 (0.7–3.2)
Trabeculectomies	2.1 (1.2–3.8)*	1.4 (0.5–4.2)
Tube surgeries	2.1 (1.2–3.7)*	2.0 (0.7–5.6)
Revisions	1.1 (0.6–2.1)	0.7 (0.2–3.7)
Transscleral diode or ECPC	7.7 (0.9–64.0)

Notes: Blank cell represents data that could not be fit to the logistic regression model.

a Multivariable logistic regression adjusting for age and sex.

* p<0.05.

Abbreviations: POAG, primary open-angle glaucoma; OR, odds ratio; IOP, intraocular pressure; ECPC, endocyclophotocoagulation.