In our large binational cohort of children with CKD, we found a direct association between CKD stage, school absences, and sport participation. Children treated with KRT were less likely to participate in sport activities, with children on dialysis and with kidney transplants participating in approximately 40% and 25% fewer sports than children with mild to moderate stage CKD, respectively. The impact of CKD stage on school attendance was modified by the duration of CKD diagnoses, with children treated with KRT who had a prolonged duration of CKD diagnosis reporting more days of school absences compared to their peers with shorter duration of CKD diagnosis.

The observed findings for sport reflect reduced levels of physical activity seen in children with CKD, particularly amongst children with advanced stage kidney disease. A cross-sectional survey of children with kidney transplants found lower levels of physical activity compared to their peers, with only 30% participating in organised sport in the past year [14]. Children with kidney transplants also took fewer steps per day and fewer minutes per day engaged in physical activity compared to children without CKD [15]. Other studies have also found lower levels of physical activity in children with earlier stages of CKD. In the United States, only 13.4% of children with CKD 3–5 met the national weekly physical activity recommendations of 60 min of physical activity daily for seven days compared to 25% of children in the general population. Additionally, the median number of team sports played in the past 12 months was one (IQR 0–2) which was similar to the median number of sports played by the participants in our cohort [10].

The sports played amongst children with CKD mirrored the popular sports played by school-aged children in the general population in Australia and New Zealand where the most popular sports are swimming, soccer, rugby/football, dance, and basketball [16, 17]. Aside from rugby/football which was played less frequently amongst children with a kidney transplant, the types of sports engagement did not differ by CKD stages. Fears about transplant kidney injury were the predominant reason for limitation in physical activity listed by children with a kidney transplant in one single centre study, where two thirds of children received counselling about restricting contact sports such as rugby and touch football [14]. This concern likely accounts for the lower participation rates of rugby/football amongst transplant recipients in our study. Whilst sport participation is reduced amongst children with CKD, particularly for those treated with KRT, our study illustrates that the types of sports played are relatively similar to the general population [16, 17].

There are many reasons for reduced sports participation amongst children on dialysis or with a kidney transplant. Prior studies have found cardiorespiratory fitness, as measured by peak oxygen consumption and muscle strength, in children on dialysis was substantially below the normal range when compared to their age-matched peers [18, 19]. Although studies have found some improvement in cardiorespiratory fitness post-transplant, it remains poorer when compared to the general population [18]. Other barriers to sport participation may include lower perceptions of sport competence amongst kidney transplant recipients, symptoms such as fatigue, medical treatments such as placement of dialysis catheters, and also concerns about potential damage to the kidney transplant [8, 15]. Patients also report issues around self-esteem, and social anxiety about peer judgement also contribute to reduced participation in sport. We hypothesise that cost constraints also likely contribute to reduced sport participation for children receiving KRT, as well as reduced time for extracurricular activities due to demands from medical treatments and attendance at hospital, and finally parental anxiety about possible injury may contribute.

Poor school attendance amongst children with CKD has been previously characterised, with 17% of children with CKD stages 1–4 missing greater than 18 days of school a year in North America, compared to 3% of the general population [9]. School absenteeism remains higher amongst children post-kidney transplant, with a mean school attendance of 85%, compared to 94% amongst peers. Frequent hospital attendance and admission were considered the major contributors to school absences [20]. We found a differential effect of CKD stage on school attendance, based on the duration of CKD. The duration of reduced kidney function over time had a profound impact on the ability to attend school. For children with kidney transplants and on dialysis, the number of missed school days increased with longer duration of CKD diagnoses. Children with CKD 1–2 missed less school if they had CKD for a longer period of time, suggesting adaptation over time. In contrast, school absences in children on dialysis were high, with little change with duration of CKD. Although children with a kidney transplant did not appear to miss more school compared to children with CKD 1–2, the amount of school they missed increased with longer duration of CKD. Taken overall, we hypothesise this suggests a cumulative effect of chronic kidney disease amongst those who progress to kidney failure. Ongoing and augmented support is needed to improve school attendance such as enhanced school liaison, assistance with transport and minimisation, and coordination of hospital visits. Previous studies have shown chronic school absence in children with CKD 1–4 is associated with enuresis and needing catheterisation, higher medication burden, hospitalisation, and presentation to the emergency department [9]. Reasons for school absenteeism reported by children with CKD stages 1–4 and their caregivers include feeling chronically unwell, having a relentless number of medical appointments, and being bullied by other students at school and extra-curricular activities [21]. Qualitative studies also suggest fatigue, illness, discomfort, and medical treatments as contributors to poor school attendance [8]. Future research is necessary to comprehensively assess the reasons behind reduced school attendance in children across all stages of CKD, which will help identify strategies to improve school attendance.

Our study has several strengths. We have, for the first time, evaluated the two key aspects of life participation in a large cohort of children with CKD spanning all stages of CKD through to KRT. Our cohort is broadly representative of school-age children with CKD in Australia and New Zealand, with representation from diverse ethnic groups and across levels of SES. Our study also has several limitations. We have not captured data on preschool-aged children and acknowledge that reduced life participation may be evident even in early childhood in children with CKD. Our measure of school absenteeism is restricted to the four weeks prior to when the questionnaire was undertaken and could be skewed by a single prolonged illness or hospitalisation. Furthermore, comparison to a general population measure of school attendance rate over a calendar year is limited. The interpretation of days of school absent was left to parents and carers, and we are unable to differentiate between full or partial day absences for children in the study. There was a higher proportion of missing school attendance data amongst children on dialysis, with comments suggesting that this was due to having high levels of school absence. This may mean we have underestimated the effect of dialysis on school attendance. We did not have granular data on physical activity such as minutes and steps per day or the setting and intensity of participation in sport. We also did not have comparative data on sport participation in children without CKD. We did not collect data on parent and caregiver participation in sport, and acknowledge this may have had a confounding effect on child sport participation. We also did not specify a time frame for sport participation in our questionnaire. Children treated with dialysis may experience more interruptions in sports activities, whilst those with early to moderate stage CKD and with stable transplants may participate in sports activities (irrespective of the types of sports) more consistently because they are less burdened by their illnesses. The other important domain of life participation identified by patients and their families was the ability to participate in social activities [8]. Whilst we asked broadly about hobbies in our questionnaires, we did not collect information about their ability to interact socially and capacity to keep up with their peers without CKD. This is important as to be fully engaged in all aspects of life participation and to have optimal psychological wellbeing the ability to form meaningful social relationships is critical. Furthermore, participation in other hobbies and activities may reduce children’s participation in sport and may partially account for the lower rates of sport participation seen in children on dialysis and with a kidney transplant.

In conclusion, findings from this large observational study highlight that life participation, evaluated by the number and types of sports played and the number of school absences, is significantly reduced amongst children with CKD, and the influence of CKD is heightened considerably amongst children treated with KRT. Children with CKD face immense challenges associated with their illness affecting all aspects of their daily lives. Healthcare professionals and policy makers may have neglected this crucial element of a child’s life with CKD. Further research is warranted to identify the barriers and solutions to improve life participation and engagement in our children with CKD. Active collaborations between healthcare providers, caregivers, and schools are needed to ensure our children have opportunities to thrive and participate in life more fully.