High Rate of Charcot Foot Attacks Early After Simultaneous Pancreas???Kidney Transplantation

Simultaneous pancreas–kidney transplantation (SPK) is a frequently used therapeutic option for patients with diabetes presenting with end-stage renal disease (1–3). As a result of an advanced stage of complications as polyneuropathy and peripheral vascular disease, most patients will be at high risk for foot complications in the early years after transplantation (4–7). Charcot arthropathy is among the most serious complications, its etiology remaining unclear (8–13). Although a high incidence and prevalence of fractures in the foot and ankle after SPK are reported, formal cases of Charcot foot (CF) are never mentioned (14–17). The aim of this study was to evaluate the prevalence of CF in SPK patients transplanted in our institution and get insight into possible predisposing factors. We performed a retrospective survey of the medical records of all patients with type 1 diabetes who underwent a SPK at our institution from 1992 until 2004 (n=66). Data collected included various parameters as date of diagnosis of diabetes mellitus and of nephropathy, mean HbA1c, mean posttransplant C-peptide, retinopathy, and number of treated acute rejection episodes. The criteria to diagnose CF met those later described by Gazis et al. (12), with the exception that an isolated fracture of the metatarsals was included. To compare patients with and without CF, a univariate analysis (Wilcoxon or Cox regression) has been performed. P values less than 0.05 were considered significant. Demographic and transplant- related characteristics are listed in Table 1. No patients had CF before transplantation. Eight of 66 patients (12%) developed CF, four of them within the first year after transplantation (summary statistics of all eight patients: 1.8±1.9 [1.2, 0.3–5.5] years). Four patients developed bilateral involvement (mean interval 1.4±2.2 [0.6, 0–4.7] years). No new CF attacks in the previously affected foot were recorded during follow up. Comparisons between patients with and without CF are shown in Table 1. Only mean pretransplant HbA1c showed a statistical significant difference with a poorer glycemic control in the CF group. Impressive was the high mortality rate in patients with CF (38 vs. 19%), also found in other CF populations (11–13). Furthermore, a higher proportion of patients with CF (75%) experienced at least one rejection episode as compared with the patients without CF (48%).TABLE 1: Demographic and transplant-related characteristics compared between patients with and without Charcot footThe prevalence of CF in our study is much higher as reported earlier in diabetic populations (8, 9). Various reasons can account for this difference. Longstanding diabetes mellitus, high HbA1c values, and nephropathy are all reported to increase the possibility to develop CF (8, 9, 11, 12) as present in the majority of our patients. The role of immunosuppressive therapy remains controversial and should sometimes be expected to be protective and beneficial rather than causal (8–10, 14–19). Several limitations of this study are evident: the retrospective design of our study, the fact that only medical records were examined, the limited number of patients included, and the lack of a group of matched patients with similar glycemic control but without SPK. Morbidity and mortality after CF presentation necessitates prompt diagnosis and treatment. Awareness of all healthcare providers is necessary, and in case of suspicion, referral to a multidisciplinary diabetic foot clinic is mandatory. Giovanni A.