Towards evidence based referral criteria for growth monitoring

Abstract

Aims: To evaluate the performance of growth monitoring in detecting diseases. Turner's syndrome (TS) is taken as the target disease.

Methods: Case-control simulation study. Three archetypal screening rules are applied to longitudinal growth data comparing a group with TS versus a reference group from birth to the age of 10 years. Main outcome measures were sensitivity, specificity, and median referral age.

Results: Clear differences in performance of the rules were found. The best rule takes parental height into account. Combining rules could improve diagnostic accuracy.

Conclusion: Growth monitoring is useful to screen for TS. A combined rule that takes absolute height SDS, parental height, and deflection in height velocity into account is the best way to do this. Similar research is needed for other diseases, populations, and ages, and the results should be synthesised into evidence based referral criteria.

Figure 1

Father's height plotted against mother's height in the reference sample. (A) Observed data from group in which both parental heights are known (n = 203). (B) Imputed (artificial) data for cases where at least one parental height is missing (n = 286). The reference line indicates the location of equal parental heights.

Figure 2

ROC plot of different scenarios under three archetypal rules. Each scenario is labeled by its parameter values according to table 1. For example, the label "(-3, -2)" in the left plot indicates the scenario with a = -3 and b = -2. Only scenarios with p = q = r = 3 (cf table 1) are plotted.

Figure 3

Median referral age of girls with TS as a function of sensitivity and specificity under each rule. Every dot corresponds to a scenario.