The obese uremic patient: a newcomer in the nephrology clinic?

This issue of the journal contains a description of three cases of impaired renal function, associated with the use of the anti-obesity drug Xenical® (orlistat) [1]. This drug has been used for more than two decades and the safety profile of orlistat, which is only absorbed to about 1%, is very well established. However, as the authors point out, this is the reason to suspect that, in some rare cases, orlistat may be the underlying reason for the development of impaired renal function and, as also suggested by the authors, there are also plausible mechanisms to explain this unfortunate development. The problem is not new and has been addressed elsewhere [2, 3]. The association of a drug used for the treatment of obesity with the development of impaired renal function, opens for an inevitable discussion about the imminent arrival of the obese subject with uremia on the clinical stage. During recent years, obesity has emerged as an upcoming risk factor associated with chronic kidney disease. In the past, patients with endstage renal disease would generally be in a catabolic situation and weight problems were not an issue. However, with the exploding obesity epidemic all over the world, there is a welldocumented increase in the prevalence of type 2 diabetes, and in a subgroup of obese patients with type 2 diabetes, the associated cardiovascular complications will lead to not only myocardial infarction and stroke, but also to impairment of the renal function, eventually leading to uremia, dialysis and transplantation [4, 5]. This is a new clinical situation which nephrologists have to face and address. Over recent years, treatment of obesity in patients with chronic kidney disease has become an issue, which doctors have never been used to in the past. Just like other clinicians trying to develop strategies to fight obesity in general, nephrologists will be confronted, since it is well known that weight loss has marked positive effects on type 2 diabetes and may even cause reversal of the disease. However, the treatment modalities for obesity are unfortunately not well developed. The classical treatment programmes consisting of diet, exercise and behaviour modification have been tried and do work under certain conditions. Generally, the short-term effects are quite acceptable in the hands of capable therapists, but the long-term results are not too promising. Very low calorie diets (VLCD) have been tried in general populations and seem to offer an interesting alternative. In a recent programme in an outpatient setting, the weight loss after 1 year was quite impressive as was weight loss maintenance [6]. Clearly, there is a role for VLCD programmes in obese individuals and such individuals also with type 2 diabetes, and this opportunity has not been fully utilised in the primary health care sector. The VLCD programmes fill a void of treatment strategies between the standard diet exercise and behaviour modification programme and the most advanced form of obesity therapy, which is bariatric surgery. It is now well established that bariatric surgery will reduce mortality in severely obese patients and improve several of the associated risk factors [7]. The first impressive results were generally associated with the improvement in glycaemic control, which was maintained for several years after bariatric surgery. Weight loss after surgery would also result in blood pressure reduction and improved lipid control, but these risk factors would begin to reappear again a few years after surgery. Summarising the results after up to 18 years of follow-up, it can be said that bariatric surgery has reduced overall mortality