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The average per-person inflation-adjusted lifetime cost of keratoconus treatment in 2019 was nearly $29,000, with a cumulative economic burden of $3.8 billion, a large retrospective cohort study showed.

In the cohort of over 69 million patients enrolled in Medicaid or the Children's Health Insurance Program (CHIP), keratoconus was most prevalent in adults ages 18 to 39, with a slightly higher rate in women (52.5% vs 47.5% in men), reported Vishal Jhanji, MD, of the Vision Institute at the University of Pittsburgh School of Medicine, and colleagues.

The second-highest prevalence was observed in adults ages 40 to 64, suggesting delayed diagnosis in this group, they noted in the .

The average proportion of cases in the Black population (31.4%) reported annually was only slightly higher than that in Caucasians (29.7%) and Hispanics (30.2%). Rates were notably higher in Black women compared with Black men (P=0.032), while the least affected groups were Asians, Caucasians, and Native Americans, with the lower prevalence in Indigenous people possibly due to a disparity in claim rates.

This is the first study to address the prevalence of keratoconus and its distribution in the population by age, sex, or race, Jhanji and team noted.

"The stratification of data on the basis of age, sex, and race will help eye care providers to be more vigilant while assessing patients belonging to groups that have higher keratoconus prevalence," Jhanji told 麻豆传媒.

Keratoconus, an ectatic disorder characterized by progressive thinning of the cornea, can cause mild to severe loss of vision related to myopic shift and irregular astigmatism. It is more common in people with serious allergies, eye-rubbing tendencies, and possibly obesity.

Vision aids such as glasses and contact lenses can help with the milder forms, but if these fail, patients may require corneal surgery, including corneal cross-linking, refractive surgery, corneal transplantation, or a combination of several approaches.

"Most of the patients who present to ophthalmologists are diagnosed, albeit a little too late," co-author Rohan Bir Singh, MD, of Massachusetts Eye and Ear at Harvard Medical School in Boston, told 麻豆传媒. "Since the clinical symptoms -- for example, blurring of vision -- occur in advanced disease with corneal thinning, treatment modalities such as corneal cross-linking might not help in complete vision recovery in all cases."

"Diagnosis of keratoconus requires advanced imaging techniques such as Pentacam and anterior segment ocular coherence tomography," Singh added. "It is highly likely that cases will be missed on visual acuity testing alone."

Commenting on the cost analysis, Masako Chen, MD, of the New York Eye and Ear Infirmary of Mount Sinai in New York City, told 麻豆传媒, "It is very helpful to know how much of an economic burden keratoconus causes; it's important for setting policies and making recommendations at the federal, local, or departmental level."

In this study, direct costs had to be calculated based on a when penetrating keratoplasty was the only approved surgical intervention for severe keratoconus. Since 2015, however, corneal cross-linking has been widely adopted as first-line treatment in selected cases, and may significantly reduce the lifetime costs for the patients.

The indirect costs due to work loss from vision impairment are a substantial component of economic costs, the authors added.

Unlike in 2011, Chen noted, corneal transplant is now reserved for end-stage disease, so data that support early detection and therapies to prevent progression to that extreme point are important.

"Insurance coverage for cross-linking has gotten better over the years, but it's still not amazing," she said. "We need to get more insurance carriers, federal and others, to cover cross-linking to save money and help patients."

This study used data reported to the CDC Vision and Eye Health Surveillance System and included patients enrolled in Medicaid and CHIP who were diagnosed with keratoconus from 2016 to 2019. The crude prevalence rates (national and state) were obtained from the database and extrapolated to estimate the keratoconus case count in the U.S.

The national prevalence of keratoconus was computed to be 0.04% in 2019, up from 0.03% in 2016.

The authors acknowledged that their analysis may have underestimated prevalence rates, since the cohort included only Medicare- and CHIP-enrolled patients and no uninsured or commercially covered patients. In addition, there were no data for five states and two overseas territories.

The authors also could not estimate the revised lifetime direct costs to patients, owing to the absence of recent data on cross-linking and corneal transplantation procedures, as noted by Chen.

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