The following appraisal has been carried out by Dr. Colin W. Pritchard BA, BPhil, MA, MSc, PhD, HonMFPH, (Research Design Service South-West).

Colin wishes us to say that this is ‘quick and dirty’ and that once he has more accurate data from the RfPB Pilot Study that has been applied for he will be able to carry out a much more definitive appraisal.

Appraisal

At present there is no definitive study of the cost effectiveness of ‘Thin Skin Protection Socks’ from an NHS perspective.  This note explores the potential reduction in NHS costs that would be associated with preventing skin tears through using these socks.

Although skin tears are recognised as a major problem for an elderly population, the current costs of these injuries to the NHS have not been described. The approach adopted here is to estimate the costs for a population of 1000 patients. Studies of the prevalence of skin tears which require treatment in care home populations report estimates ranging from 14% to 24% [1].  Taking the lower estimate, this would amount to 51,100 patient days in a population of 1000 patients. The guidelines [1] recommend a 5 day treatment cycle of assessment and dressing the injury for category I or II tears [2]. Assuming that each cycle involves 40 minutes of nurse time (estimated at £64.00/hour patient contact [3]) and two dressings (assuming the recommended atraumatic all in one dressing costed as Mepilex £5.00/dressing) each cycle of treatment would cost £52.67. 51,100 patient days gives an estimate of 10,220 treatment cycles per 1,000 patients per year at a cost of £538,287.40. This cost is likely to be an underestimate of the total cost because the treatment of category III injuries (about 15% of all injuries [4]), and those which become infected or develop into ulcers will be considerably more expensive.

There are no reliable estimates of the incidence of skin tears. The prevalence figures include patients with multiple injuries of varying severity and different rates of resolution. Conservatively, we have estimated that the at risk population will have an average of 1.7  injuries a year (1,700 tears per 1000 patients per year) with each injury taking about a month to resolve.

The effectiveness of the stockings in reducing the rate of injuries has not yet been definitively determined. Although it was a small uncontrolled study, our pilot study observed 747 patient days of wearing the cut-proof socks in patients with a history of tears. With the assumed injury rate (above) we would have expected to see about 3.5 tears over the period of the study: a higher rate of injury would have been expected in this very high risk population. In the event there was one minor (7mm) tear, 28.5% of the expected number (equivalent to a reduction of 71.5%).

The table below is based on the assumptions outlined above and shows the estimated annual costs of treatment for 1,000 patients using the socks for a range of reductions in the incidence of injury.

 

Without cut-proof socks With cut proof socks
75% reduction in injury 50% reduction in injury 25% reduction in injury
Number of injuries 1,700 425 850 1,275
Days 51,100 12,775 25,550 38,325
Prevalence 14% 3.5% 7% 10.5%
Treatment costs £538,287 £134,572 £269,144 £403,716
Sock costs £  60,000 £  60,000 £  60,000
Total costs £538,287 £194,572 £329,144 £463,716
Estimated saving £343,715 £209,143 £ 74,571

 

With the assumptions discussed above, the use of the cut proof socks will result in a saving to the NHS even when 25% of the injuries is prevented.

The estimates are based on conservative assumptions of the prevalence, incidence and costs of skin tears in the population with fragile skin who would use the socks. It is, nevertheless, possible to explore the sensitivity of the estimated savings to the assumptions that have been made to derive them. If the cut-proof socks only prevent 16% of the injuries the NHS costs would be the same whether cut-proof socks were used or not.  In the estimates above, the costs of treatment have been estimated using minimal assumptions about the severity of the tear and the development of complications to the injury. Using these assumptions, the average cost of treating a tear is £316.64. However, this estimate is based on best practice guidelines which may not reflect actual practice [5]. If the cut-proof socks prevent 25% of injuries, the cost point at which NHS costs would be equal whether the socks were used or not is £180.00. Finally, we have assumed an average of 1.7 injuries per person per year.  This is a low estimate for the population with fragile skin, however, if the average rate of injury was 0.758 the NHS costs would be the same whether cut-proof socks were used or not if they prevent 25% of the injuries.

[1] All Wales Tissue Viability Forum The Prevention and Management of Skin Tears the assessment and management of skin tears. 2011 MA Healthcare Ltd, 2011.

[2] Payne RL, Martin ML (1993) Defining and classifying skin tears: need for a common language. 1993 Ostomy Wound Manag. 39(5): 16–26

[3] Personal Social Services Research Unit (compiled Curtis L.) Unit costs of health and Social Care 2010 University of Kent.

[4] McErlean B, Sandison S, Muir D, Hutchinson B & Humphreys W. Skin tear prevalence and management at one hospital. Primary Intention 2004; 12(2): 83-86, 88

[5] Stephen-Haynes J, Callaghan R, Bethell E, Greenwood M The assessment and management of skin tears in care homes British Journal of Nursing, 2011 (Tissue Viability Supplement), Vol 20, No 11

2011©C.W.Pritchard