Validation of a Dehydration Scoring System
Condition: Dehydration
MeSH terms: Dehydration
Study type: Observational

Summary: 
      This is a study to evaluate the validity, reliability, and clinical usefulness of a new
      dehydration scoring system (DSS).
    

Detailed description: 
      RESEARCH DESIGN AND METHODS

      Objectives:

      Objective 1: Validity; Objective 2: Reliability; Objective 3: To obtain preliminary data in
      determining the effectiveness of the Dehydration Scoring System in predicting resource
      utilization and disposition.

      Study Design:

      This will be a prospective study of patients presenting to the Emergency Department (ED) with
      clinical signs of dehydration. All previously healthy children aged 1 month (mo) up to 16
      years of (yo) age with vomiting, diarrhea, or poor oral (PO) intake from presumed
      gastroenteritis will be eligible for inclusion after obtaining informed consent and assent if
      applicable. Exclusion criteria will include a history of cardiac or renal disease, diabetes
      mellitus (DM), malnutrition or failure to thrive (FTT), and any malabsorptive disorder or
      short gut syndrome . Children will further be excluded if they are clinically unstable,
      requiring immediate life saving interventions or if no parent or legal guardian is available
      for consent.

      Clinical measures:

      Upon obtaining informed consent, a data sheet will be started to gather study weights,
      dehydration scores at specified intervals, patient demographics and key clinical findings, as
      well as resource utilization (none, oral rehydration therapy (ORT), intravenous (IV) therapy,
      observation status, admission to the hospital). Information regarding whether the patients
      have received the rotavirus vaccine and how many doses will also be collected.

      As part of standard of care, patients will be weighed using either a single infant or
      pediatric scale located in triage at presentation to the Pediatric ED (PED) (Time 0) (age
      appropriate infant scale versus standing stadiometer in Triage). Infants will be weighed
      naked and older children in a hospital gown. Change in weight at discharge or follow up
      (f/u), compared to baseline is an adequate measure of dehydration that has been used
      standardly in studies of this nature.

      Emergency department nurses will obtain a dehydration score when the patient is transferred
      to a treatment room (time 0). Prior to initiation of treatment, and as close to the nurse's
      Dehydration Score as is possible, a clinician (Faculty, fellow, nurse practitioner or
      physician assistant) will also score the patient as they arrive into the treatment area prior
      to initiation of treatment. Clinicians will be masked to the initial Dehydration Score as
      scored by the nurse. Subjects will continue to receive Dehydration Scores every hour after
      the initiation of treatment until a disposition has been determined (i.e. discharge home or
      admit to hospital) (Times T1,2,3…). At discharge, or at time decision to admit has been made,
      the children will be weighed on the same scale as initially used. Subjects will be asked to
      return in 1 week (+/- 3 days) for wellness (dehydration) score, repeat weight (same scale),
      and further continuation of historical and physical examination findings. Research or
      clinical nurse will obtain the final follow-up Dehydration Score.

      STATISTICAL METHODS

      Statistical Analysis

      Objective 1: The validity of the scale, in comparison to the gold standard of change in
      weight, will be assessed by comparing the ratio of the change in dehydration score (discharge
      minus baseline) to the ratio change in weight (discharge minus baseline) for all subjects. A
      comparison will also be made between the ratio change in score and ratio change in weight
      using the measurements at follow-up. Lin's concordance correlation coefficient will be
      estimated for both comparisons. This method of measuring correlation is preferred over
      Pearson's correlation coefficient, which is limited to estimating the degree of linearity
      between the two tests and not the accuracy.

      Objective 2: Repeatability of the Dehydration Scale by different raters (nurse and clinician
      at baseline) will be tested by obtaining a concordance correlation coefficient.

      Objective 3: Correlation between Dehydration Score and resource utilization/disposition
      outcomes. We will characterize the mean dehydration scores across treatments (i.e. resource
      utilization), and roughly identify cut-points (natural or by clinical significance) and
      estimate predictive values.

      Sample size calculation: The primary aim of the proposed study is to evaluate the validity of
      the dehydration scale compared to the gold standard of change in weight. The hypothesis is
      that the correlation of the two measures will produce a correlation of at least 0.95,
      exceeding the 0.75 cut-off to demonstrate an 'excellent' correlation. To detect this
      difference at 80% power (alpha=0.05), 54 subjects will be sufficient. Assuming a significant
      loss to follow-up at one week (~40-50%), a total of 100 subjects will be targeted for
      enrollment to ensure that 54 subjects are available to test the hypothesis of a correlation
      between change in score and weight at follow-up. This estimated sample size will further be
      sufficient to evaluate interobserver reliability and obtain a concordance correlation
      coefficient.
    

Intervention name(s): weight; weight and dehydration score
Intervention type(s): Other; Other
Intervention description(s): weight and dehydration scores; weight and dehydration score
Other intervention name(s): weight and dehydration
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Dehydrated children