Cost effectiveness of collagen crosslinking for progressive keratoconus in the UK NHS

BACKGROUND

Keratoconus is a progressive degenerative corneal disorder of children and young adults that is traditionally managed by refractive error correction, with corneal transplantation reserved for the most severe cases. UVA collagen crosslinking is a novel procedure that aims to prevent disease progression, currently being considered for use in the UK NHS. We assess whether it might be a cost-effective alternative to standard management for patients with progressive keratoconus.

METHODS

We constructed a Markov model in which we estimated disease progression from prospective follow-up studies, derived costs derived from the NHS National Tariff, and calculated utilities from linear regression models of visual acuity in the better-seeing eye. We performed deterministic and probabilistic sensitivity analyses to assess the impact of possible variations in the model parameters.

RESULTS

Collagen crosslinking is cost effective compared with standard management at an incremental cost of £ 3174 per QALY in the base case. Deterministic sensitivity analysis shows that this could rise above £ 33,263 per QALY if the duration of treatment efficacy is limited to 5 years. Other model parameters are not decision significant. Collagen crosslinking is cost effective in 85% of simulations at a willingness-to-pay threshold of £ 30,000 per QALY.

CONCLUSION

UVA collagen crosslinking is very likely to be cost effective, compared with standard management, for the treatment of progressive keratoconus. However, further research to explore its efficacy beyond 5 years is desirable.

Prevalence of scoliosis in neurofibromatosis

Experience in a comprehensive, multispecialty neurofibromatosis clinic leads the authors to suggest that the association of spinal deformity with neurofibromatosis is less frequent than usually assumed. Previously reported statistics may be partly attributed to preselection of patients seen by spinal surgeons, and to the predominant referral of patients having severe manifestations of neurofibromatosis. A diagnosis of neurofibromatosis 1, based on National Institutes of Health criteria, is confirmed for two hundred twenty patients at the clinic. Twenty-three of these patients have structural scoliosis. Nine patients have idiopathic type curves, eight have dystrophic scoliosis, four have dystrophic kyphoscoliosis, and two have dystrophic lordoscoliosis. The authors believe that 10% is representative of the true prevalence of spinal deformity in an otherwise unselected cross section of neurofibromatosis patients.