Multicentre randomised control trial comparing real time teledermatology with conventional outpatient dermatological care: societal cost-benefit analysis

British Medical Journal, May 6, 2000 by R Wootton, S E Bloomer, R Corbett, D J Eedy, N Hicks, H E Lotery, C Mathews, J Paisley, K Steele, M A Loane

(*) See table 2.

([dagger]) See Results section.

([double dagger]) See table 4. Purchase of capital equipment usually incurs a standard interest charge of 6%. The normal time for depreciating electronic equipment in the NHS is seven years (NHS Executive).

Sensitivity analysis

In our trial, the break even round trip distance at which teledermatology became as cheap as conventional dermatology was 205.8 km. The main factors affecting the cost of the teledermatology consultation were additional general practitioner time, cost of purchasing equipment and depreciation, telecommunication costs, and use of equipment. The savings were reducing referrals, training benefits, reduced patient travel, and reduced patient time.

We conducted a sensitivity analysis to examine the effect of these six main factors on the comparative costs of teledermatology. If all other factors were held equal, replacing the general practitioner with a nurse practitioner made teledermatology more expensive and caused the break even round trip distance to increase to 378.9 km; using current prices for equipment caused the break even round trip distance to decrease to 131.8 km and depreciating equipment over five years instead of seven decreased the break even distance to 170.7 km; halving the telecommunications costs (both rental and call charges) caused the break even round trip distance to decrease to 177.1 km; increasing use from 0.5 patient per week to one session per week (12 patients) caused the break even distance to decrease to 77.7 km; halving the training benefits (non-referrals reduced to 10%, three equivalent training days) caused the break even distance to increase to 304.2 km.

More efficient use of the teledermatology system almost halved the costs (that is, if each health centre had one morning telemedicine session per week. With current equipment prices and keeping all the other variables exactly the same as observed in the trial, the net cost of the teledermatology consultation falls from 132 [pounds sterling] to 98 [pounds sterling]. Further details of the sensitivity analysis are available on the BMJ's website.

Discussion

We found that there were no major differences in clinical outcome between teledermatology and conventional outpatient dermatology care. The dermatologist was more likely to recommend general practice follow up of patients seen by telemedicine than conventionally, which may indicate some caution. Almost half of those who were recommended to return for a general practice follow up visit failed to do so. This implies that the videolink management advice was effective and that a return visit was deemed unnecessary by the patient. The review of patient records showed that the teledermatology patients had a lower level of reattendance to both their general practitioner and the dermatology outpatient department compared with patients seen conventionally. This is consistent with results from a randomised control trial that showed that patients make fewer return visits to a general practitioner after a joint consultation with an orthopaedic specialist.[14] However, despite the apparent clinical effectiveness, the cost of the teledermatology consultation was considerably higher per patient compared with conventional care. We examined both the costs and benefits accrued by the health service and the patient. In some ways the trial did not reflect a real life situation as the health centres were deliberately chosen because they were near the hospital. This was done to minimise patient inconvenience and encourage participation.