A questionnaire that assesses patient-reported symptoms and the impact of these symptoms on daily life activities is being developed specifically for people with neurotrophic keratitis (NK), a study reports.
Reviewed by patients in this initial validation step, it may help researchers better understand how therapies in ongoing and future clinical trials affect these people and their symptoms.
The questionnaire and this validation were described in “Development of the neurotrophic keratopathy questionnaire: qualitative research,” a study published in the Journal of Patient-Reported Outcomes.
Neurotrophic keratitis is a rare degenerative eye disease that affects the nerves serving the cornea, the transparent protective outer layer of the eye that works like a window to control and focus the entry of light.
Damage to these nerve cells leads to a loss of sensation in the cornea, lower tear production in response to stimuli, spontaneous breakdown of the corneal epithelium (the outer layer), and difficulties with healing.
Developing treatments that protect these cranial nerves is critical for these patients, as they have only one approved therapy, Oxervate (cenegermin), addressing the underlying cause of disease.
Clinical trials require that patients report changes in their symptoms over the course of treatment, providing information that clinicians cannot access through other validated measures.
Yet, there is no validated questionnaire to assess patient-reported outcomes specifically for neurotrophic keratitis And while tools used for other eye diseases address some of the symptoms experienced by individuals with NK, none adequately assesses the symptoms, signs, and impact of this disease on patients.
Researchers at Evidera, a contract research group, and Dompe — Oxervate’s developer — set out to create a tool that specifically addresses the symptoms experienced by those with neurotrophic keratitis.
Usually, the symptoms of interest are selected only after interviews with patients, and subsequent interviews are conducted to trim down and validate the draft tool. But given the rare nature of NK, researchers developed a draft prior to the interviews, based on signs and symptoms reported in the literature.
The draft tool, called neurotrophic keratopathy questionnaire (NKQ), consisted of 14 questions assessing the severity of 11 symptoms and signs, and three impacts that may be associated with the disease.
It asked patients to rate the severity of their symptoms over the past seven days on a scale of five points — from “no, not at all” to “very severe” on symptom items, and from “never” to “always” on impact items.
Participants underwent an interview, in which they were first asked to describe their diagnosis history, symptoms, and impact of their symptoms on daily life activities. Initially, participants had the opportunity to spontaneously describe their experiences, then interviewers asked about symptoms mentioned in the literature but not described by them.
After that, participants were asked to complete the draft NKQ and provide feedback regarding the clarity of the questionnaire, its comprehensiveness, importance of its items, whether the recall period was adequate, and if response options adequately described the severity of symptoms.
Fourteen patients, mean age of 65.7, who were mostly women (64%) and white (85%) participated. They had been diagnosed on average 28 months before completing these interviews, and three had participated in a clinical trial for Oxervate.
Over the interviews, patients reported 24 signs and symptoms of the disease, including redness (86%), sensitivity to light (79%), general discomfort (64%), dry eye (64%), reduced visual acuity (64%), blurred vision (57%), eye fatigue (57%), and itching (50%). Most symptoms were reported in the first five interviews.
Notably, symptoms such as redness, eye fatigue, and itching were only reported when mentioned by the interviewers. Others, such as sensitivity to light, blurred vision, and burning, were not described in the literature but were frequently reported by patients. Pain or discomfort, and inflammation were in the literature but very few patients raised them.
Among daily activity limitations, the most frequently reported included frustration (71%), driving impairment (57%), reading impairment (50%), difficulty watching television (50%), and concerns with potentially losing their eyesight (43%).
Overall, participants found the questionnaire comprehensive and easy to understand, and most found recalling symptoms over the previous seven days was enough to capture them accurately. Some thought a couple of items redundant, some needed an additional assessment option (such as “non-applicable” among quality of vision questions for people who already lost their sight), and some needed to be clarified as to whether symptoms were experienced with or without treatment.
None of the suggestions were consistent enough to warrant changes in the tool.
Researchers also noted that all symptoms reported by patients and literature were included in the draft, and there was no need to add additional items. Only minor changes were made to some items to improve consistency or comprehension.
“This study represents the first step in the development of the NKQ,” the researchers wrote. “The evidence gained in this qualitative study provides support for the content of the draft NKQ among adult patients with NK.”
Nevertheless, “additional quantitative work … is required to provide further evidence that the NKQ is fit-for-purpose in regulatory submissions and demonstrate its ability to measure the effect of new treatments on symptoms and impacts associated with NK,” they concluded.