Arising from: Kallenberg CGM and Bijl M (2008) Why rheumatologists should be involved in the treatment of lupus nephritis. Nat Clin Pract Nephrol [doi:10.1038/ncpneph0696]

The dispute between nephrologists and rheumatologists about the care of patients with lupus nephritis is a deep-rooted problem in many academic and non-academic units. As mentioned in the Viewpoint by Kallenberg and Bijl in the current issue of Nature Clinical Practice Nephrology, non-renal manifestations—with or without concomitant renal disease—are common presenting features of systemic lupus erythematosus (SLE). SLE is the prototypical autoimmune disease, and is commonly encountered in rheumatology clinics. If rheumatologists routinely refer lupus patients with nephritis to nephrologists who then take over the care of the patients, they will ultimately lose up to 80% of their SLE patients. Conversely, if nephrologists care only for patients presenting with renal symptoms, they will experience less than 10% of all cases of SLE. Both of these situations are unhealthy, especially for nephrology and rheumatology trainees who should be exposed to the whole spectrum of clinical manifestations of SLE.

Many medical units in my region of Hong Kong run joint lupus nephritis clinics that involve both rheumatologists and nephrologists. Regular renal biopsy conferences are also held with histopathologists who are experienced in the renal pathology of lupus, to discuss and reach a consensus about the clinical management of individual patients. Research studies in lupus nephritis can be performed with combined efforts of the rheumatologists, nephrologists and pathologists. Patients with lupus nephritis are best treated by a specialist who has considerable experience and expertise in the disease. This specialist might be the rheumatologist or the nephrologist, depending on the referral pattern and the rapport between patients and doctors. If such a team approach is undertaken, the practical issues raised by Bargman in her original Viewpoint,1 such as recognition of inadequate collection of urine, misinterpretation of urinary sediments and overtreatment of inactive lupus nephritis, will be easily conveyed to all the rheumatologists and nephrologists who attend the combined clinics, as well as to their fellows and trainees.

Finally, the incidence of renal disease, as defined by the American College of Rheumatology criteria, can be up to 31% at first presentation of SLE in some ethnic groups such as the Chinese.2 This figure is already an underestimation because, as mentioned in Kallenberg and Bijl's Viewpoint, the criteria exclude patients with subclinical renal disease (e.g. microscopic hematuria alone or a milder degree of proteinuria). One third of patients belonging to this category will eventually develop overt renal disease at a median of 14 months after onset of SLE.2 The figure of 3–6% quoted by Kallenberg and Bijl as the prevalence of renal disease at diagnosis of SLE probably refers to more severe renal manifestations such as nephrotic syndrome with peripheral edema, acute nephritic syndrome or impaired renal function. This subset of patients will usually be seen by a nephrologist at their first presentation. Concomitant non-renal SLE manifestations are, interestingly, rather infrequent in these patients.