International Paediatric Mitochondrial Disease Scale

Objective: There is an urgent need for reliable and universally applicable outcome measures for children with mitochondrial diseases. In this study, we aimed to adapt the currently available Newcastle Paediatric Mitochondrial Disease Scale (NPMDS) to the International Paediatric Mitochondrial Disease Scale (IPMDS) during a Delphi-based process with input from international collaborators, patients and caretakers, as well as a pilot reliability study in eight patients. Subsequently, we aimed to test the feasibility, construct validity and reliability of the IPMDS in a multicentre study. Methods: A clinically, biochemically and genetically heterogeneous group of 17 patients (age 1.6–16 years) from five different expert centres from four different continents were evaluated in this study. Results: The feasibility of the IPMDS was good, as indicated by a low number of missing items (4 %) and the positive evaluation of patients, parents and users. Principal component analysis of our small sample identified three factors, which explained 57.9 % of the variance. Good construct validity was found using hypothesis testing. The overall interrater reliability was good [median intraclass correlation coefficient for agreement between raters (ICCagreement) 0.85; range 0.23–0.99). Conclusion: In conclusion, we suggest using the IPMDS for assessing natural history in children with mitochondrial diseases. These data should be used to further explore construct validity of the IPMDS and to set age limits. In parallel, responsiveness and the minimal clinically important difference should be studied to facilitate sample size calculations in future clinical trials

Summary of available studies on the outcome of peritoneal dialysis after failed kidney allograft^b'*'.

Summary of available studies on the outcome of peritoneal dialysis after failed kidney allograftb'*'.</p

Peritoneal transport characteristics of the study population.

Comparison between the failed transplant and control groups: (A) dialysate-to-plasma ratios of creatinine at 4-hour (D/P4); and (B) mass transfer area coefficient (MTAC) of creatinine; and, within the failed transplant group, between patients who did and did not have peritoneal dialysis (PD) before transplant: (C) D/P4; and (D) MTAC creatinine. Data were compared by student’s t test.</p

STROBE statement—Checklist of items that should be included in reports of observational studies.

STROBE statement—Checklist of items that should be included in reports of observational studies.</p

Baseline biochemical characteristics of the study population.

Baseline biochemical characteristics of the study population.</p

Characteristics of the failed transplant group.

BackgroundThe result of published studies on the clinical outcome of peritoneal dialysis (PD) after kidney allograft failure is conflicting. There are also few published data on the outcome of patients who had PD before kidney transplant and then return to PD after allograft failure.MethodsWe reviewed 100 patients who were started on PD after kidney allograft failure between 2001 and 2020 (failed transplant group); 50 of them received PD before transplant. We compared the clinical outcome to 200 new PD patients matched for age, sex, and diabetic status (control group).ResultsThe patients were followed for 45.8 ± 40.5 months. the 2-year patient survival rate was 83.3% and 87.8% for the failed transplant and control groups, respectively (log rank test, p = 0.2). The corresponding 2-year technique survival rate 66.5% and 71.7% (p = 0.5). The failed transplant and control groups also had similar hospitalization rate and peritonitis rate. In the failed transplant group, there was also no difference in patient survival, technique survival, hospitalization, or peritonitis rate between those with and without PD before transplant. In the failed transplant group, patients who had PD before transplant and then returned to PD after allograft failure had substantial increase in D/P4 (0.585 ± 0.130 to 0.659 ± 0.111, paired t-test, p = 0.032) and MTAC creatinine (7.74 ± 3.68 to 9.73 ± 3.00 ml/min/1.73m2, p = 0.047) from the time before the transplant to the time after PD was resumed after failed allograft.ConclusionsThe clinical outcome of PD patients with a failed kidney allograft is similar to other PD patients. However, patients who have a history of PD before kidney transplant and then return to PD after allograft failure have increased peritoneal transport parameters.</div

Hospitalization of the study population.

Comparison between the failed transplant and control groups: (A) number of hospital admission; and (B) duration of hospitalization; and, within the failed transplant group, between patients who did and did not have peritoneal dialysis (PD) before transplant: (C) number of hospital admission; and (D) duration of hospitalization. Data were adjusted to per patient-year of follow up and compared by Mann-Whitney U test.</p

Patient and technique survival of the study population.

Kaplan Meier plots for (A) patient survival; and (B) technique survival of the failed transplant and control groups, and, within the failed transplant group, Kaplan Meier plot for (C) patient survival; and (D) technique survival for patients who did and did not have peritoneal dialysis (PD) before transplant. For patient survival, censoring events include conversion to long-term hemodialysis, kidney transplantation, transfer to other center, or loss to follow up. For technique survival, patient death and transfer to hemodialysis were taken as events, a second transplantation was treated as competing event, and censoring events include transfer to other center or loss to follow up. Data were compared by the log-rank test.</p

Demographic and clinical characteristics of the study population.

Demographic and clinical characteristics of the study population.</p

Peritonitis-free survival of the study population.

Kaplan Meier plots for (A) failed transplant versus control groups; and (B) patients who did and did not have peritoneal dialysis (PD) before transplant. Data were compared by the log-rank test.</p