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Evaluation of predictive models for six minute walk test among children with pulmonary hypertension
Sonali S Patel1, Julie C Fernie2, Amy L Taylor2
1Heart Institute, Children's Hospital Colorado, Aurora, CO, United States; University of Colorado School of Medicine, Aurora, CO, United States.
Insights
Existing six minute walk distance (6MWD) prediction equations are inaccurate for children with pulmonary hypertension (PH). A new, validated equation is presented for better medical care and management of pediatric PH patients.
Area of Science:
- Pediatric Cardiology
- Pulmonary Hypertension Research
- Clinical Assessment Tools
Background:
- Existing six minute walk distance (6MWD) prediction equations are based on healthy children and have small sample sizes.
- Children with pulmonary hypertension (PH) often have smaller stature, making current pediatric 6MWD equations a poor fit.
- There is a lack of validated 6MWD prediction equations specifically for children with PH.
Purpose of the Study:
- To assess the accuracy of five existing pediatric 6MWD prediction equations in children with PH, stratified by World Health Organization (WHO) functional class.
- To develop and validate a new predictive equation for 6MWD tailored to children with PH.
Main Methods:
- Retrospective analysis of 711 six minute walk tests (6MWTs) in children aged 4-18 years with PH.
- Evaluation of existing pediatric 6MWD prediction equations against actual patient data.
- Development and validation of a novel 6MWD prediction equation using an additional 65 6MWTs.
Main Results:
- Existing pediatric 6MWD prediction equations significantly overestimated walk distance in children with PH.
- The discrepancy between predicted and actual 6MWD increased with higher WHO functional classes (III and IV).
- The newly developed prediction equation demonstrated a superior goodness of fit across all WHO classes compared to existing equations.
Conclusions:
- Current 6MWD prediction equations for healthy children are unreliable for pediatric PH populations, especially in advanced disease stages.
- The new prediction equation offers a validated reference for the medical care and management of children with PH (WHO classes I-IV).
- This validated equation is crucial for accurate functional capacity assessment in pediatric PH.
Background:
Existing six minute walk distance (6MWD) prediction equations were developed using healthy children and include relatively small sample sizes. Children with congenital heart disease and pulmonary hypertension (PH) are often small-for-age, so the existing pediatric prediction equations are likely a poor fit for children with PH. Currently, there are no equations for 6MWD among children with PH.
Objectives:
Evaluate the validity of five existing pediatric prediction equations among the 6MWD of children with PH, including for each World Health Organization (WHO) class. Develop a validated predictive equation for use in children with PH.
Methods/Results:
The 6MWDs from 711 six minute walk tests (6MWTs) of children aged four through 18years with PH were analyzed retrospectively and were evaluated against existing pediatric prediction equations. Existing pediatric prediction equations overestimated the walk distance among our population. The predicted distances versus actual distances were significantly different for each WHO class, with higher class associated with greater difference. A new prediction equation for 6MWD among children with PH was developed and validated with 65 additional 6MWTs. Our prediction equation demonstrates higher goodness of fit for all WHO classes than the preexisting pediatric equations.
Conclusions:
Existing prediction equations for 6MWD among healthy children are not accurate for children with PH, particularly for children with more advanced stages of the disease (WHO classes III and IV). We present a new prediction equation for children with PH (WHO classes I through IV) that provides reference for medical care and management.
