Costs and outcomes over 36 years of patients with phenylketonuria who do and do not remain on a phenylalanine-restricted diet.
Lifelong PKU diet looks pricey on paper, but letting adults quit costs the NHS more in the long run.
01Research in Context
What this study did
Guest et al. (2013) built a computer model of UK NHS care for adults with PKU. They tracked what happens if people stay on the low-phenylalanine diet for 36 years versus if they drop it. The model used real clinic visits, blood tests, and special food costs.
No new patients were enrolled. The team fed national data into spreadsheets to predict long-term spending.
What they found
The lifetime bill for one PKU patient ranges from £21k to £149k. Most of the money goes to special foods and drinks, not hospital stays.
The big surprise: most adults stop the diet, skip drinks, and miss blood checks. That under-treatment keeps the total cost lower than it could be, but it also lets brain damage quietly continue.
How this fits with other research
Hatton et al. (1999) looked at the first year after restarting the diet and saw costs drop by about £20k per adult. Their short view shows quick savings that the 36-year model never captures. The two studies sit side-by-side: one proves fast pay-off, the other shows the long price of letting people quit.
Case studies like Raslear et al. (1992) and Bailey et al. (2000) report calmer behaviour and sharper attention when adults return to the diet. F et al. did not count these quality-of-life gains in pounds, so the model may under-value staying on treatment.
Lawer et al. (2009) and Spriggs et al. (2015) show that small UK learning-disability services can add checks or therapy without raising total cost. Their message is the same as F et al.: spend a little now on support, save a lot later on crisis care.
Why it matters
You can take this paper to your next team meeting and argue for tighter PKU follow-up. Point to the £20k first-year saving from C et al. and the 36-year price tag from F et al. Together they make a dollars-and-sense case for funding diet clinics, travel vouchers, and behaviour support. Even if the special drink looks expensive, letting adults quit costs more in lost skills and later crises.
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02At a glance
03Original abstract
BACKGROUND: To quantify the costs and consequences of managing phenylketonuria (PKU) in the UK and to estimate the potential implications to the UK's National Health Service (NHS) of keeping patients on a phenylalanine-restricted diet for life. METHOD: A computer-based model was constructed depicting the management of PKU patients over the first 36 years of their life, derived from patients suffering from this metabolic disorder in The Health Improvement Network database (a nationally representative database of patients registered with general practitioners in the UK). The model was used to estimate the incidence of co-morbidities and the levels of healthcare resource use and corresponding costs over the 36 years. RESULTS: Patients who remained on a phenylalanine-restricted diet accounted for 38% of the cohort. Forty-seven per cent of patients discontinued their phenylalanine-restricted diet between 15 and 25 years of age. Of these, 73% remained off diet and 27% restarted a restricted diet at a mean 30 years of age. Fifteen per cent of the cohort had untreated PKU. Eleven per cent of patients who remained on a phenylalanine-restricted diet for 36 years received the optimum amount of prescribed amino acid supplements. Patients had a mean 12 general practitioner visits per year and one hospital outpatient visit annually, but phenylalanine levels were only measured once every 18 to 24 months. The mean NHS cost (at 2007/08 prices) of managing a PKU sufferer over the first 36 years of their life was estimated to range between £21 000 and £149 000, depending on the amount of prescribed nutrition they received. CONCLUSION: The findings suggest that the majority of patients with PKU were under-treated. The NHS cost of patient management should not be an obstacle to encouraging patients to remain on a restricted diet until further information becomes available about the long-term clinical impact of stopping such a diet. Nevertheless, patients require counselling and managed follow up regardless of the choices they make about their diet.
Journal of intellectual disability research : JIDR, 2013 · doi:10.1111/j.1365-2788.2012.01568.x