A cost of illness model to estimate the annual societal costs of X-linked retinitis pigmentosa (XLRP) in the United Kingdom (UK).

OBJECTIVE

To estimate the annual per-patient costs in the United Kingdom (UK) for each stage (disease severity) of X-linked retinitis pigmentosa (XLRP), a rare retinal disease that progressively leads to visual impairment/blindness.

METHODS

The EXPLORE XLRP-2 study enrolled patients with XLRP (n = 168) and their informal caregivers (n = 68) in 10 countries. EXPLORE XLRP-2 outcomes including health care costs/resource use (e.g. health care visits, concomitant medications), comorbidities, productivity loss, out-of-pocket costs, welfare payments, and XLRP management costs were used to estimate the annual costs for mild, moderate, or severe XLRP. A human capital approach was used to calculate patients' productivity losses; an opportunity cost approach was used to calculate the value of time spent on informal caregiving.

RESULTS

Total annual costs of XLRP in the UK were estimated to be £57,386 per patient for mild XLRP, £72,372 for moderate XLRP, and £103,127 for severe XLRP. The cost of managing XLRP is greatest for those with worse disease. For all XLRP severity levels, the largest drivers of total costs were caregivers' opportunity costs and patients' productivity losses.

CONCLUSION

Our UK-focused cost model demonstrates that the societal costs associated with XLRP tend to be higher in patients with more severe disease and are driven primarily by considerable opportunity costs for caregivers and productivity losses for patients. Health care resource use has little impact on the total cost. With no treatment currently available for XLRP, the high economic burden of the disease rests not with health care payers but mainly with patients and their caregivers.