Evaluation of the Patient-Specific Functional Scale for monitoring paediatric injury patients at a zonal referral hospital in Northern Tanzania.

Background: Injuries are a major cause of morbidity and mortality among paediatric populations in low- and middle-income countries (LMICs). The Patient-Specific Functional Scale (PSFS) is a commonly used tool to assess functional recovery. This study aims to evaluate the psychometric properties of the PSFS for monitoring paediatric injury patients at a zonal referral hospital in Northern Tanzania.

Methods: This retrospective cohort study used data from the Kilimanjaro Christian Medical Centre paediatric injury registry (November 2020 to June 2024) and included patients under 18 years treated for injuries at a zonal referral hospital in Northern Tanzania. Key outcomes were in-hospital mortality and injury-related morbidity, assessed using the PSFS and Glasgow Outcome Scale Extended Paediatric (GOS-E Ped). The PSFS's reliability was tested with Cronbach's alpha, its smallest meaningful change was calculated and its correlation with GOS-E Ped was analysed using Spearman's rank.

Results: Among 1000 paediatric injury patients, the mortality rate was 6.6%. PSFS mean scores improved from 4.3 at discharge to 6.5 at 2 weeks and 9.0 at 3 months post hospital discharge. The PSFS showed good reliability (Cronbach's alpha: 0.90). A moderate negative correlation was found between PSFS and GOS-E Ped at 3 months (Spearman's ρ: -0.74). The minimally clinically important difference was 2.7, with a sensitivity of 0.73, specificity of 0.72 and an area under the curve of 0.83.

Conclusion: The PSFS was found to be a valid, reliable and responsive tool for assessing functional changes in paediatric injury patients, demonstrating strong internal consistency. The findings support its use to measure morbidity in this population.