There is no solid evidence of the optimum monitoring schemes (e.g., frequency and timing of visits, technologies to be used for detecting progression) for patients with manifest glaucoma and ocular hypertension. Some modeling and retrospective studies suggest that more treatment could allow less frequent monitoring visit in ocular hypertension and stable glaucoma. One RCT suggests that shared care may save costs.
Finnish retrospective study of the impact resource utilization on quality of life and clinical findings
The cost data of glaucoma patients were retrospectively collected and compared in two cities in Finland during 11 years. The patients were examined at the end of follow-up period. In addition, general health related quality of life questionnaire was evaluated. Intensive monitoring frequency, treatment and spending did not lead to better quality of life in glaucoma patients, i.e. 28% higher medication costs, 46% higher diagnostic testing and follow-up costs, 3 times more laser therapies and twice more surgery between the two cities.There was actually a statistically significant counter-intuitive difference in the early glaucoma group, i.e. patients using more resources reported worse quality of life «Hagman J. Comparison of resource utilization in th...»1.
Systematic review and UK simukalion model
The UK Health Technology Assessment compared five alternative surveillance and treatment pathways in OHT.
The two most intensive pathways were based on the NICE guidelines (check-ups from every 4-12 -month to 6-24 -month intervals depending on initial risk), two further pathways followed biennial follow-up schemes differing in location (surveillance either in hospital or in primary care), and in the fifth ‘Treat all' pathway, all IOPs > 21 mmHg were treated with prostaglandins. In ‘Treat all' pathway, IOP was measured annually in community optometry with referral to a hospital only if IOP reduction was <15%.
The results of the model indicated no clear benefit from intensive monitoring in OHT. ‘Treat all' was the least and ‘NICE intensive' was the most costly pathway.
Compared to 'Treat all' –strategy, however, the pathway with 2-year check ups in an eye hospital (and treatment with > 5% glaucoma risk in 5 years) reduced the incidence of conversion to glaucoma and provided more QALYs. However, simultaneously this pathway cost considerably more - above the limit of the society's willingness to pay in the UK «Burr JM, Botello-Pinzon P, Takwoingi Y ym. Surveil...»2.
For the cost-benefit analysis the biennial hospital pathway was the only pathway relative to ‘no surveillance' that had a positive net benefit.
Systematic review and simulation model (Holland)
An economic simulation model in Holland (built on systematic evaluation of literature)
The results suggested that treating all OHT patients with IOP > 21 mmHg would be cost saving compared to watchful waiting – even if 43% of the simulated untreated OHT patients never converted to glaucoma in their entire lifetime.
In eyes with manifest glaucoma, in lieu of 'guessing' the initial target pressure and redefining it according to rate of progression, the model suggested to aim at a standard IOP < 15 mmHg in all glaucoma patients - even if it the model indicated that 72% would need direct combination therapy and 46% would require glaucoma surgery. According to the model, these simplified strategies would decrease demand for intensive monitoring.
Non-adherence to the medication was not considered in the model. It was assumed that including adherence would have a small impact of the outcomes but would have unnecessarily increased the complexity of the model «van Gestel A. Glaucoma management. Economic evalua...»3.
Simulation model
The report aims to determine if identification of progression would be improved by clustering tests at the beginning and end of the 2-year period. Published recommendations suggest three visual field tests per year are required to identify rapid progression in a newly diagnosed glaucomatous patient over 2 years.
Computer-simulated "patients" were given a rapid VF (mean deviation [MD]) loss of -2 dB/year with added MD measurement variability. Linear regression of MD against time was used to estimate progression. One group of "patients" was measured every 6 months, another every 4 months, whereas the wait-and-see group were measured either 2 or 3 times at both baseline and at the end of a 2-year period. Stable "patients" (0 dB/year) were generated to examine the effect of the follow-up patterns on false-positive (FP) progression identification.
By 2 years, 58% and 82% of rapidly progressing patients were correctly detected using evenly spaced 6- and 4-month VFs, respectively. This power of detection significantly improved to 62% and 95% with the wait-and-see approach (P < 0.001). When compared with evenly spaced VFs, the rate of MD loss was better estimated by the wait-and-see approach, but average detection time was slightly slower. Evenly spaced testing incurred a significantly higher FP rate: up to 5.9% compared with only 0.4% in wait-and-see (P < 0.001).
Authors' conclusions:Compared with an evenly spaced follow-up, wait-and-see identifies more "patients" with rapid VF progression with fewer FPs, making it particularly applicable to clinical trials «Crabb DP, Garway-Heath DF. Intervals between visua...»4.
Simulation model (Australia)
An economic simulation model of alternative options for the organization and delivery of clinical services in the ophthalmology department of a public hospital in Australia.
The data were sourced from routinely collected waiting and appointment lists, patient record data, and the published literature.
Patient-level costs and quality-adjusted life years were estimated for a range of alternative scenarios, including combinations of alternate follow-up times, booking cycles, and treatment pathways.
The model shows that a) extending booking cycle length from 4 to 6 months, b) extending follow-up visit times by 2 to 3 months, and c) using laser in preference to medication are more cost-effective than current practice at the study clinic «Crane GJ, Kymes SM, Hiller JE ym. Accounting for c...»5.
RCT on shared care (Holland)
The study was an economic evaluation conducted alongside a large randomised controlled trial. Four analytic perspectives were analyzed: the hospital, the patient, health care, and society in Holland. The time horizon was 30 months.
866 patients were randomised to usual care (glaucoma specialist) or a glaucoma follow-up unit (care from optometrists and ophthalmic technicians).
For quality of care, the authors found no outcomes with statistically significant differences between the interventions. For all perspectives, the costs were reduced with the glaucoma follow-up unit.
From a societal perspective the incremental cost-effectiveness ratio with the glaucoma follow-up unit, compared with usual care, was a saving of EUR 27 per 0.1 increase in overall patient satisfaction, per year.
The cost-effectiveness plane indicated that in 70% of simulations the glaucoma follow-up unit was more effective and less costly than usual care «Holtzer-Goor KM, van Sprundel E, Lemij HG ym. Cost...»6.