Background: Patients diagnosed with advanced primary open-angle glaucoma are at a high risk of lifetime blindness. Uncertainty exists about whether primary medical management (glaucoma eye drops) or primary surgical treatment (augmented trabeculectomy) provide the best and safest patient outcomes.
Objectives: To compare primary medical management with primary surgical treatment (augmented trabeculectomy) in patients with primary open-angle glaucoma presenting with advanced disease in terms of health-related quality of life, clinical effectiveness, safety and cost-effectiveness.
Design: This was a two-arm, parallel, multicentre, pragmatic randomised controlled trial.
Setting: Secondary care eye services.
Participants: Adult patients presenting with advanced primary open-angle glaucoma in at least one eye, as defined by the Hodapp-Parrish-Anderson classification of severe glaucoma.
Intervention: Primary medical treatment - escalating medical management with glaucoma eye drops. Primary trabeculectomy treatment - trabeculectomy augmented with mitomycin C.
Main outcome measures: The primary outcome was health-related quality of life measured with the Visual Function Questionnaire-25 at 2 years post randomisation. Secondary outcomes were mean intraocular pressure; EQ-5D-5L; Health Utilities Index 3; Glaucoma Utility Index; cost and cost-effectiveness; generic, vision-specific and disease-specific health-related quality of life; clinical effectiveness; and safety.
Results: A total of 453 participants were recruited. The mean age of the participants was 67 years (standard deviation 12 years) in the trabeculectomy arm and 68 years (standard deviation 12 years) in the medical management arm. Over 65% of participants were male and more than 80% were white. At 24 months, the mean difference in Visual Function Questionnaire-25 score was 1.06 (95% confidence interval -1.32 to 3.43; p = 0.383). There was no evidence of a difference between arms in the EQ-5D-5L score, the Health Utilities Index or the Glaucoma Utility Index. At 24 months, the mean intraocular pressure was 12.40 mmHg in the trabeculectomy arm and 15.07 mmHg in the medical management arm (mean difference -2.75 mmHg, 95% confidence interval -3.84 to -1.66 mmHg; p < 0.001). Fewer types of glaucoma eye drops were required in the trabeculectomy arm. LogMAR visual acuity was slightly better in the medical management arm (mean difference 0.07, 95% confidence interval 0.02 to 0.11; p = 0.006) than in the trabeculectomy arm. There was no evidence of difference in safety between the two arms. A discrete choice experiment updated the utility values for the Glaucoma Utility Index. The within-trial economic analysis found a small increase in the mean EQ-5D-5L score (0.04) and that trabeculectomy has a higher probability of being cost-effective than medical management. The incremental cost of trabeculectomy per quality-adjusted life-year was £45,456. Therefore, at 2 years, surgery is unlikely to be considered cost-effective at a threshold of £20,000 per quality-adjusted life-year. When extrapolated over a patient's lifetime in a model-based analysis, trabeculectomy, compared with medical treatment, was associated with higher costs (average £2687), a larger number of quality-adjusted life-years (average 0.28) and higher incremental cost per quality-adjusted life-year gained (average £9679). The likelihood of trabeculectomy being cost-effective at a willingness-to-pay threshold of £20,000 per quality-adjusted life year gained was 73%.
Conclusions: Our results suggested that there was no difference between treatment arms in health-related quality of life, as measured with the Visual Function Questionnaire-25 at 24 months. Intraocular pressure was better controlled in the trabeculectomy arm, and this may reduce visual field progression. Modelling over the patient's lifetime suggests that trabeculectomy may be cost-effective over the range of values of society's willingness to pay for a quality-adjusted life-year.
Future work: Further follow-up of participants will allow us to estimate the long-term differences of disease progression, patient experience and cost-effectiveness.
Trial registration: Current Controlled Trials ISRCTN56878850.
Funding: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 72. See the NIHR Journals Library website for further project information.
Keywords: ADVANCED OPEN-ANGLE GLAUCOMA; AUGMENTED TRABECULECTOMY; MITOMYCIN C; PRIMARY MEDICAL MANAGEMENT; QUALITY OF LIFE; RANDOMISED CONTROLLED TRIAL.
Glaucoma is an eye condition in which the intraocular pressure is too high, causing damage to the optic nerve and loss of vision. Patients with severe vision loss at diagnosis are the most at risk of blindness in their lifetime. Lowering pressure in the eye is the only way to prevent further vision loss. Two treatments to lower pressure are commonly used: using eye drops or having an operation known as a trabeculectomy. In England, Wales and Northern Ireland, the National Institute for Health and Care Excellence recommends surgery as the first treatment. However, we do not know which treatment is best for preventing vision loss or which is safest, has the best patient experience or provides the best value for money for the NHS. Therefore, surgery is not usually carried out in the first instance and patients start with eye drops instead. This study compared whether starting treatment with eye drops affected the quality of life of patients with advanced glaucoma more or less than starting treatment with trabeculectomy. We also investigated if initial treatment with surgery and initial treatment with eye drops were equally good at controlling pressure and were equally safe, and how much each treatment cost the NHS. Every patient had an equal chance of starting treatment with surgery or eye drops and they participated in the study for 2 years. We found that quality of life was similar regardless of treatment. Those starting with surgery had lower pressure and needed far fewer types of eye drops than those starting with eye drops. Thirty-nine patients in the eye drop arm required surgery to control their glaucoma. Initial treatment with eye drops was cheaper over 2 years’ follow-up. Our study suggests that, over a 2-year period, having surgery in the first instance lowers intraocular pressure more than eye drops and is equally as safe as eye drops. Although eye drops are a cheaper treatment option for the NHS, if the effects of surgery on intraocular pressure are lasting, then the increased cost may be justified.