RESUMEN
Vitamin D was investigated as a prognostic biomarker in COVID-19, in relation to both disease susceptibility and outcomes in infected individuals. Patients admitted to the hospital with a confirmed COVID-19 diagnosis were included if they had a vitamin D measurement prior to hospitalization. Using age- and sex-matched controls, vitamin D levels were investigated for an association with COVID-19 related hospitalizations. Further, vitamin D levels were investigated for an association with 30-day mortality in hospitalized COVID-19 patients. Additionally, three meta-analyses were conducted, investigating the association of vitamin D with the following outcomes: Having a positive SARS-CoV-2 test, hospitalization with COVID-19, and mortality in COVID-19 patients. A total of 685 hospitalized COVID-19 patients were included in the single-center study. Compared to controls, they had higher vitamin D levels. Unadjusted analysis of these 685 cases found higher vitamin D levels associated with increased 30-day mortality. This association disappeared after adjusting for age. In the fully adjusted model, no association between vitamin D and 30-day mortality was found. The meta-analyses found significant associations between lower vitamin D and having a positive SARS-CoV-2 test, and mortality among hospital-admitted COVID-19 patients. The relationship between lower vitamin D and COVID-19 related hospital admissions trended towards being positive but was not statistically significant. Many factors seem to influence the associations between vitamin D and COVID-19 related outcomes. Consequently, we do not believe that vitamin D in and of itself is likely to be a clinically useful and widely applicable predictor for the susceptibility and severity of COVID-19 infections.
Asunto(s)
COVID-19 , Deficiencia de Vitamina D , Humanos , Vitamina D , Prueba de COVID-19 , Pronóstico , SARS-CoV-2 , Vitaminas , Biomarcadores , Estudios RetrospectivosRESUMEN
BACKGROUND: Infliximab (IFX) is a monoclonal antibody used to treat patients with inflammatory bowel disease (IBD). For IFX therapeutic drug monitoring (TDM), the most commonly used analysis is enzyme-linked immunosorbent assays (ELISA) which do not allow results to be provided in real-time. The aim of this study was to compare the in-house ELISA (Promonitor IFX) with the much faster assay Quantum Blue® IFX (QB) for quantification of serum IFX concentration among IBD patients in maintenance IFX therapy. METHODS: We studied 30 serum samples from outpatients in IFX maintenance therapy at Copenhagen University Hospital Hvidovre, Denmark. Samples were used to compare IFX measurements from Promonitor IFX with QB. Therapeutic intervals of <3⯵g/mL, 3-7⯵g/mL and >7⯵g/mL were equally covered. Differences were evaluated using Bland-Altman plots and Student t-test. Correlation was evaluated using x,y-plot and Pearson's correlation coefficient. The intermediate imprecision (CV%) of QB was measured at two levels (3⯵g/mL and 7⯵g/mL). For qualitative comparison, weighted kappa statistics (κ) were determined after stratification of results by therapeutic interval. RESULTS: Promonitor IFX and QB were strongly correlated (râ¯=â¯0.92, pâ¯<â¯0.001). The mean difference between Promonitor IFX and QB was -0.57⯵g/mL (pâ¯=â¯0.2). The CV% of QB was 16.3% at 3⯵g/mL and 16.7% at 7⯵g/mL. Classification of results according to therapeutic interval showed almost perfect agreement (κâ¯=â¯0.81). CONCLUSIONS: QB is a suitable alternative to Promonitor IFX for TDM in patients treated with IFX for IBD. The results revealed a strong correlation between methods, in particular at lower IFX concentrations, representing the most interesting clinical range. When the samples were stratified according to the therapeutic interval, an almost perfect agreement between the methods was observed.
Asunto(s)
Monitoreo de Drogas/métodos , Ensayo de Inmunoadsorción Enzimática/métodos , Fármacos Gastrointestinales/sangre , Enfermedades Inflamatorias del Intestino/sangre , Infliximab/sangre , Sistemas de Atención de Punto , Dinamarca , Fármacos Gastrointestinales/uso terapéutico , Hospitales Universitarios , Humanos , Enfermedades Inflamatorias del Intestino/tratamiento farmacológico , Infliximab/uso terapéutico , Investigación CualitativaRESUMEN
BACKGROUND: Deviation in blood collection procedures is a central source of preanalytical variation affecting overall analytical and diagnostic precision. The procedure of venous blood collection for ionized calcium is hypothesized to affect analytical results. Here, we evaluate the effect of blood collection with and without a discard tube, and storage duration on results of P-Ionized Calcium (pH adjustedâ¯=â¯7.4). METHODS: We collected 100 paired venous blood tubes from randomly selected outpatients using a winged blood collection. No discard tube was drawn before the first tube. The samples were divided in five subsamples, stored at 4°-6⯰C at 24 (nâ¯=â¯20), 48 (nâ¯=â¯20), 72 (nâ¯=â¯20), 96 (nâ¯=â¯20) and 120â¯h (nâ¯=â¯20) after venipuncture, and analyzed for P-Ionized Calcium (pH adjustedâ¯=â¯7.4) on Konelab 60i (Thermo Scientific, Finland). Differences between first and second tubes were evaluated for all samples (nâ¯=â¯100) and for subsamples divided by storage duration, using Bland-Altman plot and Wilcoxon's rank-sum test. RESULTS: P-Ionized Calcium (pH adjustedâ¯=â¯7.4) results ranged from 1.13 to 1.37â¯mmol/L. We observed no statistical significant differences between the first and the second tube when comparing all samples. Dividing samples by storage duration, a statistically significant difference was found (pâ¯=â¯.0068) after 120â¯h, but the difference of individual samples was not clinically relevant. CONCLUSIONS: Our study has shown no significant difference between P-Ionized Calcium (pH adjustedâ¯=â¯7.4) values for the first and second tubes. Hence, the use of a discard tube is not required. A statistically significant difference was found on samples stored 120â¯h but was not considered clinically relevant.