1284 could increase substantially the number of operations without additional staff. A rejected transplant subjects the patient to danger and unhappiness but the quality of life on dialysis leaves much to be desired, both diet and fluid intake being restricted, and the physical and psychological dependence on the machine has to be endured with fortitude by the patients and their relatives. A well-functioning transplant, however, restores the patient fully to the community. One important cause for the shortage of donor kidneys is apathy in the medical profession and this state of mind is apparently shared by you. centres
Department of Surgery, University of Cambridge Clinical School, Addenbrooke’s Hospital,
R. Y. CALNE
Cambridge CB2 2QQ
STATISTICS AND RENAL TRANSPLANTATION
SIR,-We agree with Dr Knapp’s comments (Nov. 19, p. 1068) about misleading statistics on the results achieved by dialysis and by transplantation in the treatment of chronic renal failure. With
few notable exceptions’ most series compare transand dialysis as alternatives, which essentially they are not. Most people now regard dialysis and transplantation as constituents of combined of chronic renal failure rather than as alternatives. Unfortunately, the statistical consequence of this is being learned only very slowly, so conclusions are still being drawn from faulty premises. Transplantation is regarded with suspicion as a life-shortening procedure while home dialysis is made the treatment of choice. The patient in end-stage renal failure with an endogenous creatinine clearance of 3 ml/min has to be treated by dialysis or transplantation. Artificial kidneys are more readily available than cadaver organs, so there is no real choice at the start of treatment. Such a choice does exist for the occasional patient for whom there is a live related donor, but in Europe, more than 85% of renal grafts are from cadavers. So long as donor kidneys are scarce most patients will be dialysed at first (D), transplanted later (T) if a suitable organ becomes available, and eventually dialysed again (D) after rejection (combined treatment, D-T-D). Some patients will be treated by dialysis alone (D) when there is a contraindication to transplantation or no organ available, so the true choice lies between D-T-D and D alone. In Marburg inclusion of transplantation in the management of chronic renal failure did improve the survival-rate over that in patients for whom transa
plantation
management
plantation was not available.2 We are confident that similar conclusions could be drawn from the vast European Dialysis and Transplant Association material if only it were analysed in the proper way, but the E.D.T.A. registry has still to produce the figures. Conventional statistical presentation of data within E.D.T.A. is invaluable as a means of comparison between different centres and should be continued, but for a realistic evaluation of transplantation and dialysis the statistical approach suggested above should be
adopted. Medical Clinic,
University of Marburg, 3550 Marburg, West Germany
H. LANGE R. A. HOFFMANN
MONITORING RENAL FUNCTION AFTER TRANSPLANTATION
SiR,-Dr Knapp and his colleagues (Dec. 3, p. 1183) do service 1. 2.
to
renal
a
transplantation by suggesting the use of serum-
Mathew, T. H., Marshall, V. C., Vibraman, P., Hill, A. V. L., Johnson, W., McOmish, D., Morris, P. J., Kincaid-Smith, P. Lancet, 1975, ii, 137. Lange, H., Claas, G., Hoffmann, R. A., Himmelmann, G., Rodeck, G. Aktuelle Urol. 1976, 7, 297.
creatinine plotted graphically in the assessment of renal-graft function. Graphical representation does allow one to follow trends in changes in renal function as assessed by serumcreatinine. However, I doubt whether plotting serum-creatinine on reciprocal (hyperbolic) graph paper will avoid the pitfalls of assessing renal function by serum-creatinine measurements. The particular area of dispute is the patient with a low serum-creatinine. Changes at this end of the scale are exaggerated by the logarithmic scale. Knapp et al. argue that such a change, which is seen to be significant when plotted logarithmically, indicates rejection or a change in renal function. However, it is with low levels of serum-creatinine that errors in biochemical determination can result in small changes of serum-creatinine which will be magnified by the logarithmic scale. Many of us have struggled over the decision as to whether to institute anti-rejection therapy when the serumcreatinine changes from, for example, 130 to 150 fLmol/l. Those of us who have been restrained from giving therapy have been rewarded by a value of 120 mol/1 the following day. Those who have started anti-rejection therapy have claimed beneficial results from that therapy when the serumcreatinine has fallen. In the example given by Knapp et al. no one would doubt the significance of a rise of serum-creatinine from 130 jjmol/1 on day 9 to 190 p.mol;1 on day 10 and 240 µmol/l on day 11, whether these results are plotted on ordinary graph paper, semilogarithmic graph paper, or simply observed as they are written down. I agree with Knapp et al. that the serum-creatinine should be measured again if there be a suspicious increase. Whether most clinical chemistry departments would agree to carry this out "several times daily" is something which could be put to the test. As a long-established plotter of renal function and hsematological measurements in renal-transplant patients, I support the principle of monitoring function in this way, but I think that Knapp et al. expect too much from the apparent simplification of the plot by the reciprocal (hyperbolic) scale. Nuffield Transplant Unit, Western General Hospital, Edinburgh EH4 2XU
J. L. ANDERTON
POVIDONE IODINE IN WOUND INFECTION
SIR,-Contrary to the statement by Mr Galland and his colleagues (Nov. 19, p. 1048) povidone iodine has been shown significantly to reduce wound infection in general surgical practice. Sanderson and 11 found that interparietal installation of povidone iodine resulted in a significant reduction in wound in a wide variety of abdominal procedures infection (p
Department of Surgery, University of Cambridge Clinical School, Addenbrooke’s Hospital,
R. Y. CALNE
Cambridge CB2 2QQ
STATISTICS AND RENAL TRANSPLANTATION
SIR,-We agree with Dr Knapp’s comments (Nov. 19, p. 1068) about misleading statistics on the results achieved by dialysis and by transplantation in the treatment of chronic renal failure. With
few notable exceptions’ most series compare transand dialysis as alternatives, which essentially they are not. Most people now regard dialysis and transplantation as constituents of combined of chronic renal failure rather than as alternatives. Unfortunately, the statistical consequence of this is being learned only very slowly, so conclusions are still being drawn from faulty premises. Transplantation is regarded with suspicion as a life-shortening procedure while home dialysis is made the treatment of choice. The patient in end-stage renal failure with an endogenous creatinine clearance of 3 ml/min has to be treated by dialysis or transplantation. Artificial kidneys are more readily available than cadaver organs, so there is no real choice at the start of treatment. Such a choice does exist for the occasional patient for whom there is a live related donor, but in Europe, more than 85% of renal grafts are from cadavers. So long as donor kidneys are scarce most patients will be dialysed at first (D), transplanted later (T) if a suitable organ becomes available, and eventually dialysed again (D) after rejection (combined treatment, D-T-D). Some patients will be treated by dialysis alone (D) when there is a contraindication to transplantation or no organ available, so the true choice lies between D-T-D and D alone. In Marburg inclusion of transplantation in the management of chronic renal failure did improve the survival-rate over that in patients for whom transa
plantation
management
plantation was not available.2 We are confident that similar conclusions could be drawn from the vast European Dialysis and Transplant Association material if only it were analysed in the proper way, but the E.D.T.A. registry has still to produce the figures. Conventional statistical presentation of data within E.D.T.A. is invaluable as a means of comparison between different centres and should be continued, but for a realistic evaluation of transplantation and dialysis the statistical approach suggested above should be
adopted. Medical Clinic,
University of Marburg, 3550 Marburg, West Germany
H. LANGE R. A. HOFFMANN
MONITORING RENAL FUNCTION AFTER TRANSPLANTATION
SiR,-Dr Knapp and his colleagues (Dec. 3, p. 1183) do service 1. 2.
to
renal
a
transplantation by suggesting the use of serum-
Mathew, T. H., Marshall, V. C., Vibraman, P., Hill, A. V. L., Johnson, W., McOmish, D., Morris, P. J., Kincaid-Smith, P. Lancet, 1975, ii, 137. Lange, H., Claas, G., Hoffmann, R. A., Himmelmann, G., Rodeck, G. Aktuelle Urol. 1976, 7, 297.
creatinine plotted graphically in the assessment of renal-graft function. Graphical representation does allow one to follow trends in changes in renal function as assessed by serumcreatinine. However, I doubt whether plotting serum-creatinine on reciprocal (hyperbolic) graph paper will avoid the pitfalls of assessing renal function by serum-creatinine measurements. The particular area of dispute is the patient with a low serum-creatinine. Changes at this end of the scale are exaggerated by the logarithmic scale. Knapp et al. argue that such a change, which is seen to be significant when plotted logarithmically, indicates rejection or a change in renal function. However, it is with low levels of serum-creatinine that errors in biochemical determination can result in small changes of serum-creatinine which will be magnified by the logarithmic scale. Many of us have struggled over the decision as to whether to institute anti-rejection therapy when the serumcreatinine changes from, for example, 130 to 150 fLmol/l. Those of us who have been restrained from giving therapy have been rewarded by a value of 120 mol/1 the following day. Those who have started anti-rejection therapy have claimed beneficial results from that therapy when the serumcreatinine has fallen. In the example given by Knapp et al. no one would doubt the significance of a rise of serum-creatinine from 130 jjmol/1 on day 9 to 190 p.mol;1 on day 10 and 240 µmol/l on day 11, whether these results are plotted on ordinary graph paper, semilogarithmic graph paper, or simply observed as they are written down. I agree with Knapp et al. that the serum-creatinine should be measured again if there be a suspicious increase. Whether most clinical chemistry departments would agree to carry this out "several times daily" is something which could be put to the test. As a long-established plotter of renal function and hsematological measurements in renal-transplant patients, I support the principle of monitoring function in this way, but I think that Knapp et al. expect too much from the apparent simplification of the plot by the reciprocal (hyperbolic) scale. Nuffield Transplant Unit, Western General Hospital, Edinburgh EH4 2XU
J. L. ANDERTON
POVIDONE IODINE IN WOUND INFECTION
SIR,-Contrary to the statement by Mr Galland and his colleagues (Nov. 19, p. 1048) povidone iodine has been shown significantly to reduce wound infection in general surgical practice. Sanderson and 11 found that interparietal installation of povidone iodine resulted in a significant reduction in wound in a wide variety of abdominal procedures infection (p
