Prognosis of cryptogenic fibrosing alveolitis.

interpretation are just as great. In the extreme case, when the results of trials are still being hotly debated (as, for example, in the question of patients with myocardial infarction), the findings of cost-effectiveness studies could become too controversial to be useful. A distinction is usually drawn between cost-effectiveness and cost-benefit analysis. The former measures only the various effects of procedures, while the latter attempts to express the effects (benefits) in terms of money. It is at this stage that rarefied discussions of the value of life and health begin to dominate the reports. Though potentially useful frameworks have been developed,3 there is no agreement on how we should value the so-called "intangible" outputs of the Health Service.4 For this reason, cost-effectiveness analysis is the more practicable and useful procedure. Ross et al have published data on the effectiveness of cardiac surgery on the quality of life. Some 20 months after operation 68%1" of patients reported no limitation on activity, and 740,, of men were in full-time employment, compared with 12%o and 33% respectively before operation. So, given that these comparisons genuinely reflect effectiveness, we may ask if cardiac surgery is good value for money. The answer will depend on comparison with alternative ways of spending it. Unfortunately, because of the problems referred to, we have few comparable data for other procedures. Perhaps renal transplantation is one other technique for which we have the most comprehensive follow-up data, for virtually the whole European experience is recorded in the computer files of the European Dialysis and Transplant Association. As a result, we can say with confidence that the output of renal specialists varies between about £1000 per year of "good quality" life (for patients with a functioning transplant) and f 11 000 per year of "poorer quality" life (for patients treated with hospital dialysis). 6 Such confidence, however, is unusual. Bunker et al7 have collected a series of cost-effectiveness studies of surgery from America and Britain. All these have made the best of such data that exist, with the aid of simplifying assumptions. Sometimes the results of the analysis are convincing. For example, Neutra,8 extrapolating data from White" to the whole of America, estimated that careful observation and evaluation of all diagnostic information before appendicectomy could save 170 deaths, 6 million convalescent days, and $370m in averted treatment costs per year. Appendicectomy lends itself to measurement of costs because the expected benefits (such as lives saved and reduced number of days with disability) are easily assessable immediately after operation. Furthermore, the results of this study were clear cut because the greater the care taken before operation the greater the benefit. In many other cases the analysis can contribute little to any debate. Thus Bunker et al,7 considering the cost-effectiveness of elective hysterectomy, judged that the procedure had no significant effect on the expectation of life. So we have to alter the central question to the effect of the operation on the quality of life. But we then find no convincing data on benefits in these terms: on the one hand, the woman may lose her symptoms from fibroids or her menstrual discomfort; on the other hand, the operation itself may have unpleasant sequelae. A constant theme running through all the discussions on cost-effectiveness studies is how fragmentary are the data on which calculations have to be based. Moreover, few of the controlled evaluative trials that have been done can be compared with one another. There is a strong case for closer co-operation between clinicians and economists, especially in large and expensive multicentre trials. Not only would this ensure that trials generate useful data: it would also mean that these produce results that are sufficiently standardised to allow us to make true comparisons between the alternative ways of spending money in the NHS.