Background: Therapeutic drug monitoring of tacrolimus (Tac) is mandatory in solid organ transplant (SOT) recipients. Finger-prick microsampling is more flexible and tolerable during the therapeutic drug monitoring of tacrolimus and has been shown to be applicable in adult SOT recipients. In this study, a previously validated method applying volumetric absorptive microsampling (VAMS) to measure Tac in adults was cross-validated in a pediatric population. Methods: Patients with SOT scheduled for standard posttransplant follow-up visits were recruited. Blood samples were obtained by trained phlebotomists using standard venipuncture and capillary microsampling, before the morning dose of Tac as well as 2 and 5 hours after dosing. Tac concentrations were quantified using liquid chromatography–tandem mass spectrometry. Concordance between Tac concentrations obtained with venipuncture and VAMS was evaluated using Passing–Bablok regression, calculation of absolute and relative differences, and percentage of samples within ±20% and ±30% difference. Results: A total of 39 SOT patients aged 4–18 years (22 male) were included. The median (range) predose venous blood concentration was 4.8 (2.6–13.6) mcg/L, with a difference between VAMS and venous blood samples of −0.2 ± 0.7 mcg/L. The relative mean difference was −1.3% [95% confidence interval (CI), −5.9% to 3.4%]. Ninety-two percent and 97% of the sample pairs demonstrated differences within ±20% and ±30%, respectively. Postdose (2 hours and/or 5 hours, n = 17) median concentration in venous blood was 7.9 (4.8–19.2) mcg/L. The difference between VAMS and venous blood samples was 0.1 ± 1.0 mcg/L, with a relative mean difference of −2.5% (95% confidence interval, −8.8% to 3.8%). Eighty-eight percent of the postdose sample pairs were within ±20% difference, and all were within ±30% difference. Conclusions: Tac concentrations can be accurately measured using VAMS technology in pediatric SOT recipients. This makes home-based Tac monitoring feasible in the pediatric population.

Background. The transition from pediatric to young adult care is a vulnerable period for the renal transplant patient. We aimed to identify medication nonadherence (noninitiation, nonimplementation, and nonpersistence) and graft loss rates among adolescents and young adults and elucidate the influence of the transition phase on transplant outcomes. Methods. A retrospective nationwide cohort analysis of all renal transplantations in Norway from 2000 to 2020 was performed. Data were retrieved from the Norwegian Renal Registry, and adherence data from hospital charts. Patients transplanted aged <50 y, with functioning graft at 6 mo, were included. Recipients transplanted aged <26 y were compared with recipients transplanted aged 26–50 y. Graft loss, acute rejection, and development of de novo donor-specific antibodies were assessed in relation to the transition phase, defined as 14–26 y. Results. Data from 1830 kidney recipients were included: 371 (20%) transplanted <26 y (64% male, 68% living donor) versus 1459 transplanted 26–50 y (63% male, 44% living donor). There were 298 graft losses, 78 (21%) in the <26-y group versus 220 (15%) in the 26- to 50-y group. During the transition phase, 36 grafts were lost, 29 (81%) after transfer to the adult service. Medication nonadherence was the reason for 58% (21 of 36) of the losses during the transition phase, versus 12% (27 of 220) in the 26- to 50-y group ( P < 0.001). The 5-y graft survival rate was 89% (95% confidence interval, 85%-92%) and 94% (92%-95%), respectively ( P = 0.01). Conclusions. Nonadherence was verified as the main cause of kidney graft loss in the transition phase.

Background: Several studies have associated elevated C-reactive protein (CRP) levels to the occurrence of atrial fibrillation (AF). We sought to estimate the frequency and prognostic impact of AF in patients with bacteremia, and to study the possible association between AF and CRP as well as between AF and mortality in this population. Methods: We retrospectively evaluated patient charts of patients with bacteremia with Escherichia coli or Streptococcus pneumoniae admitted to the Aker University Hospital in Oslo between 1994 and 2004. Known cardiac risk factors for AF, signs and mode of conversion of AF, and, if applicable, date of death were registered, as were characteristics of infection, such as systemic inflammatory response syndrome and white blood cell count. Initial CRP values were categorized into 4 strata. Odds ratios of the 3 highest CRP categories compared with the lowest were obtained from logistic models adjusting for known cardiac risk factors for AF as well as possible factors that may have had an impact on the odds ratios for the different CRP levels. Cox regression analysis was used to compare new-onset AF and death during the first 2 weeks after hospitalization. Results: A total of 672 patient charts were studied; 104 patients (15.4%) had new-onset AF. Peak incidence of new-onset AF occurred on the day of admission. Peak CRP values were reached during the following 2 days. High CRP level at admission did not predict the occurrence of AF. The observed mortality was higher among patients with new-onset AF (p = 0.001) during the first 2 weeks after hospitalization, but this effect disappears when adjusted for relevant factors. Conclusions: The frequency of new-onset AF in bacteremia is substantial. Initial CRP levels or white blood cell count do not seem to predict new-onset AF, as opposed to systemic inflammatory response syndrome. On the other hand, in patients with bacteremia, new-onset AF should be viewed as an indicator of increased mortality and morbidity.