Cross-validation of comorbidity items in two national databases in a sample of patients with end-stage kidney disease.

BACKGROUND: The use of national medico-administrative databases for epidemiological studies has increased in the last decades. In France, the Healthcare Expenditures and Conditions Mapping (HECM) algorithm has been developed to analyse and monitor the morbidity and economic burden of 58 diseases. We aimed to assess the performance of the HECM in identifying different conditions in patients with end-stage kidney disease (ESKD) using data from the REIN registry (the French National Registry for patients with ESKD). METHODS: We included all patients over 18 years of age who started renal replacement therapy in France in 2018. Five conditions with a similar definition in both databases were included (ESKD, diabetes, human immunodeficiency virus [HIV], coronary insufficiency, and cancer). The performance of each SNDS algorithm was assessed using sensitivity, specificity, positive predictive values (PPVs), negative predictive values (NPVs), and Cohen's kappa coefficient. RESULTS: In total 5,971 patients were included. Among them, 81% were identified as having ESKD in both databases. Diabetes was the condition with the best performance, with a sensitivity, specificity, PPV, NPV, and Kappa coefficient all over 80%. Cancer had the lowest level of agreement with a Kappa coefficient of 51% and a high specificity and high NPV (94% and 95%). The conditions for which the definition in the HECM included disease-specific medications performed better in our study. CONCLUSION: The HECM showed good to very good concordance with the REIN database information overall, with the exception of cancer. Further validation of the HECM tool in other populations should be performed.

A methionine-free diet associated with nitrosourea treatment down-regulates methylguanine-DNA methyl transferase activity in patients with metastatic cancer.

BACKGROUND: Methionine (MET) depletion used in association with chemotherapy improves the therapeutic index in animal models. This potentiating effect may be due to tumor cell sensitization to chloroethylnitrosoureas through their MET dependency and the down-regulation of O6- methylguanine-DNA methyltransferase (MGMT). Our purpose was to evaluate the impact of the association of a dietary MET restriction with nitrosourea treatment on MGMT activity in peripheral blood mononuclear cells (PBMCs). PATIENTS AND METHODS: Six patients with metastatic cancer (melanoma and glioma) received 4 cycles of a MET-free diet with cystemustine (60 mg/m2). RESULTS: MGMT activity in PBMCs decreased by an average of 13% from 553+/-90 fnol/mg before the diet to 413+/-59 fmol/mg after the diet + chemotherapy period (p=0.029). The decrease of MGMT activity was not affected by the duration of the MET-free diet period but seems to be correlated to the plasma MET depletion induced by the MET-free diet.

Phase II trial of the association of a methionine-free diet with cystemustine therapy in melanoma and glioma.

BACKGROUND: In a previous phase I clinical trial of dietary methionine (MET) restriction with cystemustine treatment for melanoma or glioma, we determined the optimal MET-free diet duration to be 1 day. On this basis, a phase II clinical trial was initiated to evaluate safety and efficacy of this combination. PATIENTS AND METHODS: Twenty-two patients (20 with metastatic melanoma and 2 with recurrent gloma) received a median of 4 cycles of the association of a 1-day MET-free diet with cystemustine (60 mg/m(2)) every two weeks. RESULTS: This association was well tolerated (toxicity and nutritional status). Toxicity remained mainly hematological and consisted of WHO grade 3-4 thrombocytopenia, leucopenia and neutropenia in 36, 27 and 27% of patients respectively. The median disease-free survival was 1.8 months and the median survival was 4.6 months, with 2 long-duration stabilizations. The plasmatic MET depletion obtained was of 40 + or - 31%.

[Methionine dependency of cancer cells: a new therapeutic approach?]. / Dépendance en méthionine des cellules cancéreuses: une nouvelle approche thérapeutique?

Metabolic abnormalities of tumor cells offer opportunities of therapeutic targeting. In contrast to normal cells, tumor cells have absolute requirement for methionine (Met), an essential amino acid. Many molecular mechanisms have been considered to explain Met dependency. Several approaches have been used To reduce Met in vivo. As the main Met source was food, synthetic Met free diet were widely used. Alternatively, Met restriction was archived by the use of Met analogs or enzymatic degradation by methioninase. In animal models, Met restriction permit to limit tumor growth and to reduce tumor volume. However, interruption of Met restriction induce the regrowth of tumor. Moreover Met restriction induce several cells modifications suggesting its use in association with conventional chemotherapy. Preclinical studies have shown synergistic effect of the association of Met restriction and different cytostatic agents. Currently, few clinical investigations have been realised to test this therapeutic strategy.

Optimal methionine-free diet duration for nitrourea treatment: a Phase I clinical trial.

In animal models, methionine (MET) restriction in association with chloroethylnitrosoureas led to a substantial improvement. On this basis, we initiated a Phase I clinical trial of dietary MET restriction in association with chloroethylnitrosourea (cystemustine) treatment for patients with recurrent glioma or metastatic melanoma. Our purpose was 1) to determine the optimal MET-free diet duration for a maximum depletion of plasma MET and 2) to evaluate the feasibility of this association. A total of 10 patients received 4 cycles of 2 wk of an association of a MET-free diet of 1, 2, 3, or 4 consecutive days and cystemustine (60 mg/m(2)). For each cycle, plasma MET concentrations, nutritional status (weight, albumin, prealbumin) and toxicity were measured. Conversely, fed-state concentrations of plasma MET (12 AM) were reduced by dietary MET restriction, with an optimal depletion of 41% at the 1st day of MET-free diet without effect of the extending MET-free diet period. Indeed, we demonstrated the feasibility, that is, good diet acceptability and good tolerance (nutritional status and toxicity), of the association of a MET-free diet and cystemustine treatment. Based on these results, a Phase II clinical trial has been initiated to test the activity of the association of a 1-day MET-free diet with cystemustine treatment.