Evaluation of Vision-Related Quality of Life in Chinese Patients With Leber Hereditary Optic Neuropathy and the G11778A Mutation

Leber hereditary optic neuropathy in Czechia and Slovakia: Quality of life and costs from patient perspective

Introduction

Leber hereditary optic neuropathy (LHON) is the most frequent mitochondrial disease causing dyschromatopsia and progressive central visual loss that is subacute in progression and painless. Several studies have been published assessing QoL in patients with LHON, but no estimate of the economic burden has been reported to date. This study aims to quantify direct non-medical and indirect costs (productivity loss) incurred by LHON patients and their informal caregivers in Czechia and Slovakia, as well as to assess their quality of life.

Methods

The study was performed in 27 adults and children with LHON. To determine the socioeconomic burden of LHON, separate questionnaires for adults, children, and their parents were developed, including demographic and socioeconomic data. The following data were collected: age, education, family size, severity of LHON, non-medical direct and indirect costs of LHON.

Results

The mean age of adult respondents was 36.1 years (SD 13.1; n = 21). The total cost of absenteeism was EUR 1003 per person/year in adult employees, and EUR 2711 per person/year in children's parents. The productivity loss as a consequence of LHON due to combined relative absenteeism and relative presenteeism was estimated at EUR 9840 per an adult patient/year, and EUR 6298 per a parent/year, respectively. The mean cost of informal care was estimated at EUR 4502 (SD 4772; n = 6) per person/year. The mean VFQ-25 score for adult patients with LHON was 43.47 (SD 15.86).

Conclusion

The results of this study clearly show that patients with LHON and their families face an extensive socioeconomic burden related to this rare disease. Early, timely and appropriate access to diagnosis, treatment, and reimbursement decisions, but also to psychological counselling and services may help the patients and their relatives adapt and cope with the challenging aspects of vision loss and life with the disease.

Leber hereditary optic neuropathy gene therapy

PURPOSE OF REVIEW

To discuss relevant clinical outcomes, challenges, and future opportunities of gene therapy in Leber hereditary optic neuropathy (LHON).

RECENT FINDINGS

Results of G11778A LHON Phase 3 randomized clinical trials with unilateral intravitreal rAAV2/2-ND4 allotopic gene therapy show good safety and unexpected bilateral partial improvements of BCVA (best-corrected visual acuity) with mean logMAR BCVA improvements of up to near ∼0.3 logMAR (3 lines) in the treated eyes and ∼0.25 logMAR (2.5 lines) in the sham-treated or placebo-treated fellow eyes. Final mean BCVA levels after gene therapy were in the range of ∼1.3 logMAR (20/400) bilaterally.

SUMMARY

Bilateral partial improvement with unilateral LHON gene therapy was unanticipated and may be due to treatment efficacy, natural history, learning effect, and other mediators. The overall efficacy is limited given the final BCVA levels. The sequential progressive visual loss and varied occurrence of spontaneous partial improvement in LHON confound trial results. Future clinical trials with randomization of patients to a group not receiving gene therapy in either eye would help to assess treatment effect. Promising future LHON gene therapy strategies include mitochondrially-targeted-sequence adeno-associated virus ('MTS-AAV') for direct delivery of the wild-type mitochondrial DNA into the mitochondria and CRISPR-free, RNA-free mitochondrial base editing systems. Signs of anatomical optic nerve damage and objective retinal ganglion cell dysfunction are evident in the asymptomatic eyes of LHON patients experiencing unilateral visual loss, indicating the therapeutic window is narrowing before onset of visual symptoms. Future treatment strategies utilizing mitochondrial base editing in LHON carriers without optic neuropathy holds the promise of a more advantageous approach to achieve optimal visual outcome by reducing disease penetrance and mitigating retinal ganglion cell loss when optic neuropathy develops.

Leber Hereditary Optic Neuropathy Gene Therapy: Longitudinal Relationships Among Visual Function and Anatomical Measures

PURPOSE

To assess longitudinal relationships among visual function and anatomical measures of gene therapy in G11778A Leber hereditary optic neuropathy (LHON).

DESIGN

Phase 1 clinical trial.

METHODS

This was a single-institution study of patients with G11778A LHON. Patients with chronic bilateral visual loss >12 months (group 1, n = 11), acute bilateral visual loss <12 months (group 2, n = 9), or unilateral visual loss (group 3, n = 8) were administered unilateral intravitreal AAV2(Y444,500,730F)-P1ND4v2 injection with low, medium, high, and higher doses to worse eye for groups 1 and 2 and better eye for group 3. Oucome measures were best-corrected visual acuity (BCVA), visual field mean deviation (VF MD), steady-state pattern electroretinogram (SS-PERG), optical coherence tomography (OCT) retinal nerve fiber layer (RNFL) thickness and ganglion cell+inner plexiform layer (GCIPL) thickness, and National Eye Institute Visual Function Questionnaire (NEI-VFQ-25) scores. Mean follow-up was 33.6 months (range = 18-36 months).

RESULTS

Baseline SS-PERG amplitude was much reduced in both eyes of all groups including asymptomatic eyes of group 3, and showed no appreciable changes irrespective of disease stage and treatment. Significant and progressive GCIPL and RNFL thinning occurred in all eyes; BCVA and VF MD fluctuated in treated and fellow eyes, with some eyes having modest improvement that may be related to natural history or to gene therapy. Mean NEI-VFQ-25 scores declined in group 3 subjects (P = .023), CONCLUSION: Asymptomatic eyes in LHON patients with unilateral visual loss may be beyond the window of effective neuroprotection given reduced GCIPL and SS-PERG. Randomization of patients to an untreated control group would help to assess treatment effect by accounting for variable natural history. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Leber's Hereditary Optic Neuropathy with Mitochondrial DNA Mutation G11778A: A Systematic Literature Review and Meta-Analysis

Background

LHON is a progressive disease with early disease onset and male predominance, usually causing devastating visual loss to patients. These systematic review and meta-analysis are aimed at summarizing epidemiology, disease onset and progression, visual recovery, risk factors, and treatment options of Leber's hereditary optic neuropathy (LHON) with mitochondrial DNA mutation G11778A from current evidence.

Methods

The PubMed database was examined from its inception date to November 2021. Data from included studies were pooled with either a fixed-effects model or a random-effects model, depending on the results of heterogeneity tests. Sensitivity analysis was conducted to test the robustness of results.

Results

A total of 41 articles were included in the systematic review for qualitative analysis, and 34 articles were included for quantitative meta-analysis. The pooled estimate of proportion of G11778A mutation among the three primary mutations of mitochondrial DNA (G11778A, G3460A, and T14484C) for LHON was 73% (95% CI: 67% and 79%), and the LHON patients with G11778A mutation included the pooled male ratio estimate of 77% (76% and 79%), the pooled age estimate of 35.3 years (33.2 years and 37.3 years), the pooled onset age estimate of 22.1 years (19.7 years and 24.6 years), the pooled visual acuity estimate of 1.4 LogMAR (1.2 LogMAR and 1.6 LogMAR), and the pooled estimate of spontaneous visual recovery rate (in either 1 eye) of 20% (15% and 27%).

Conclusions

The G11778A mutation is a prevalent mitochondrial DNA mutation accounting for over half of LHON cases with three primary mutations. Spontaneous visual recovery is rare, and no effective treatment is currently available.

Psychometric Validity of the Visual Function Index in Leber Hereditary Optic Neuropathy

Purpose

The purpose of this study was to determine the psychometric validity of the Visual Function Index (VF-14) for use by patients with Leber hereditary optic neuropathy (LHON).

Methods

Rasch analysis was conducted in two stages using data for 196 individuals (74.5% male) carrying one of the three primary LHON mutations and affected by vision loss. In stage 1, scale unidimensionality, scale-to-sample targeting, response category threshold ordering, item fit statistics, local dependency, and reliability were assessed. In stage 2, iterative post-hoc revisions of the VF-14 structure (VF-14R) were applied and psychometrically re-evaluated.

Results

Issues identified with the VF-14 included disordered response thresholds (12/14 items), local dependency (10/91 pairwise dependencies), and evidence of multidimensionality. However, the distribution of person estimates and item thresholds were fairly well matched, only one item showed misfit to the Rasch model, and there was good reliability (Person Separation Index 0.84). Rasch-informed VF-14 revisions included removing both driving items and the misfitting sports item, rescoring response options across all items by merging two response categories, and accounting for the dependency between two reading items. The VF-14R demonstrated improved psychometric validity.

Conclusions

Clinicians and researchers using the VF-14 with LHON patients should be aware of its limitations. Compared to the original version, the proposed Rasch-based structure of the VF-14R appears to offer improved psychometric performance and interpretation of vision-related activity limitation.

Translational Relevance

The original version of the VF-14 exhibits several limitations that undermines its psychometric validity as a patient-reported outcome measure for patients with LHON.

The Impact of Leber Hereditary Optic Neuropathy on the Quality of Life of Patients and Their Relatives: A Qualitative Study

BACKGROUND

Leber hereditary optic neuropathy (LHON) is an inherited mitochondrial disease characterized by severe bilateral vision loss and chronic visual impairment. The objective of this study was to comprehensively explore the impact of LHON on the lives of patients and their relatives at the time of diagnosis and now.

METHODS

Qualitative study design with 8 focus group interviews conducted in France, Germany, the United Kingdom, and the United States, involving 17 individuals with m.11778G&gt;A mutation and their relatives. Separate focus groups for patients and their relatives were facilitated by a moderator in French, German, or English. Qualitative analysis of interviews using a pre-defined analytical framework.

RESULTS

Participants reported feeling devastated by the diagnosis of LHON after a lengthy and worrisome diagnostic journey. Patients were frustrated by the loss of autonomy, which also affected their relatives. Participants described challenges across several domains: physical capabilities, emotional well-being, interpersonal relationships, work and studies, finances, and recreational activities. Access to disability allowances, vision aids, and funded or subsided idebenone varied by country, resulting in unequal financial impact. Patients are hopeful for therapy that would restore autonomy and improve their ability to enjoy a fulfilling life, while alleviating the demands placed on their relatives.

CONCLUSIONS

The impact of LHON extends beyond vision-related activity limitations. Addressing the psychosocial impact of LHON and helping patients and their relatives adapt and cope with vision loss are vital. As part of this, an accurate and timely diagnosis is important to enable early intervention. Further investigation of specific unmet needs is required.

Capturing the experiences of patients with inherited optic neuropathies: a systematic review of patient-reported outcome measures (PROMs) and qualitative studies

PURPOSE

To identify and comprehensively evaluate studies capturing the experience of individuals affected by an inherited optic neuropathy (ION), focusing on patient-reported outcome measures (PROMs) and qualitative studies where the health status and quality of life (QoL) of these individuals have been explored.

METHODS

Systematic review of five databases using a search strategy combining four concepts: (1) ION; (2) QoL and health status; (3) PROMs; and (4) qualitative research. Studies assessing the impact of ION on any QoL domain using a PROM or qualitative methodology were included and appraised, using criteria based on the COSMIN checklist (for PROM studies) and the CASP checklist (for qualitative studies).

RESULTS

Of 1326 unique articles identified, six studies were included. Five PROMs were identified: Visual Function Index (VF-14); Hospital Anxiety and Depression Scale (HADS); a novel graphical online assessment tool (NGOAT) for reporting emotional response to vision loss; a new PROM informed by the DSM-V Criteria for Major Depressive Disorder; and an interpersonal and career 'impact rating' PROM. The psychometric performance of included PROMs were poorly described. Qualitative studies found that vision loss resulted in psychosocial losses including loss of social and communication skills and loss of independence and freedom. Factors that modified the response to vision loss were also identified.

CONCLUSION

The current PROMs used by individuals with ION have poor content coverage, primarily measuring activity limitation and emotional well-being, and insufficient reporting of psychometric performance. There is a need to develop a PROM for individuals ION to report their experiences of living with their condition.

Smoking and alcohol, health-related quality of life and psychiatric comorbidities in Leber's Hereditary Optic Neuropathy mutation carriers: a prospective cohort study

Background

Leber’s hereditary optic neuropathy (LHON) is a rare mitochondrial disorder, characterized by acute or subacute bilateral vision loss, frequently leading to significant chronic disability, mainly in young people. The causal LHON mutations of the mitochondrial DNA have incomplete penetrance, with the highest risk of disease manifestation for male mutation carriers in the second and third decades of life. Here we evaluated smoking, alcohol drinking habits, health-related quality of life (QOL) and psychiatric comorbidities in a cohort of LHON patients and asymptomatic mutation carriers from a tertiary referral centre.

Methods

Cross-sectional analysis of the ongoing Munich LHON prospective cohort study. Participants included all LHON patients and asymptomatic LHON mutation carriers older than 16 years at baseline, who were recruited between February 2014 and June 2015 and consented to participate. General, neurological and ophthalmological investigations were performed, including validated questionnaires on smoking, alcohol drinking habits, depressive symptoms and health-related QOL.

Results

Seventy-one participants were included, 34 LHON patients (82% male) and 37 asymptomatic mutation carriers (19% male). Median age at baseline was 36 years (range 18–75 years). For LHON patients, median age at visual loss onset was 27 years (9 to 72 years). Smoking is more frequent in LHON patients than asymptomatic LHON mutation carriers, and significantly more frequent in both groups than in the general population. Sixty percent of LHON patients, who smoked at disease onset, stopped or significantly reduced smoking after visual loss onset, yet 40% of LHON patients continued to smoke at study baseline. Excessive alcohol consumption is more frequent in male LHON patients than in LHON asymptomatic and more frequent than in the male general population. Further, female asymptomatic LHON mutation carriers are at risk for depression and worse mental QOL scores.

Conclusions

Given the high prevalence of smoking and excessive drinking in LHON mutation carriers, implementing effective measures to reduce these risk factors may have a significant impact in reducing LHON disease conversion risk. The underrecognized prevalence of mental health issues in this population of LHON mutation carriers highlights the need for awareness and more timely diagnosis, which may lead to improved outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-021-01724-5.