Low diagnostic yield of glaucoma referrals among young adults suggests need for guidelines
Key takeaways:
- Of 6,827 adults aged 18 to 40 years referred for glaucoma evaluation, only 8% were diagnosed within 2 years.
- A model based on age, IOP and cup-to-disc ratio effectively stratified patients as high or low risk.
Standardized glaucoma referral guidelines based on risk factors such as age, IOP and cup-to-disc ratio could improve care and efficiency, especially for patients aged 18 to 40 years, according to a study published in JAMA Network Open.
As glaucoma can lead to irreversible vision loss, patients with glaucoma risk factors, such as elevated IOP and enlarged cup-to-disc ratio (CDR), should be referred for in-office evaluation and diagnostic testing, researchers noted.
“However, there is a paucity of clear guidelines about referral criteria and evidence supporting the effectiveness of current referral practice patterns,” Tanner Frediani, BS, of Keck School of Medicine at the University of Southern California, and colleagues wrote.
This inspired them to perform a retrospective cohort study to investigate the outcomes of glaucoma referrals among adults aged 18 to 40 years in the Kaiser Permanente Southern California (KPSC) managed health care system, which does not have standardized evidence-based guidelines for glaucoma referrals.
The study included 292,453 patients (mean age, 29.8 years) who underwent first-time eye examinations with a KPSC optometrist or ophthalmologist between January 2013 and December 2018. The KPSC eye care professionals refer patients with glaucoma or suspected glaucoma for visual field testing and/or OCT based on clinical suspicion.
The primary endpoint of the study was glaucoma diagnosis within 2 years of the initial eye examination.
According to the results, 12,050 patients (52.3% women; 43.4% Hispanic) were referred for glaucoma evaluation, of whom 6,827 ( 56.7%) were evaluated with visual field or OCT testing within 2 years.
Of the evaluated group, 563 patients (8.2%) were diagnosed with glaucoma, including open-angle (61.1%), angle-closure (5%), secondary (14.9%) and unspecified (19%).
Multivariable logistic regression analyses adjusted for age, sex and race, and ethnicity showed that male sex (OR = 1.55; P = .02), moderate and high myopia (OR = 2.24; P = .005), elevated IOP (OR = 1.19 per 1 mm Hg; P < .001) and a greater CDR (OR = 1.53 per 0.1 unit; P < .001) were associated with higher odds for glaucoma.
The researchers also found that dichotomized age, IOP and CDR logistic regression models successfully stratified patients into high- and low-risk groups based on likelihood of glaucoma diagnosis. Only 51 of 1,613 patients (3.2%) in the low-risk group were diagnosed with glaucoma vs. 202 of 1,477 (13.7%) of the high-risk group.
Notably, among patients who met the low-risk criteria — aged younger than 32 years, IOP less than 18 mm Hg and CDR less than 0.7 — the negative predictive value for glaucoma diagnosis was 98.2%.
Finally, the models showed that of the 6,827 evaluated patients, 28.2% had a predicted risk below 2.5%. If this risk threshold were implemented, this model could reduce such referrals by almost 30%, the authors wrote.
The researchers noted several limitations to this study, including that the time span for glaucoma diagnosis was only 2 years, and patients evaluated after this may have been missed.
“This study provided a framework for evaluating the outcomes of glaucoma referrals and establishing standardized risk-stratification guidelines that may improve the equity of eye care and efficiency of resource utilization,” Frediani and colleagues wrote.
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