How Well Do Nigerian Heath Staff Interpret Weight Trajectory On Growth Charts In Children Under 6 Months?
Authors: Wright Charlotte M , Ezeofor Ifeyinwa , Garcia Ada 
Published: November 2023

Growth charts are widely used in developing countries to assess nutritional status over time in young infants, but little is known about how well they are interpreted.

Objectives

to test the extent to which health staff consider the pattern of weight gain over time, or just current weight centile and how this is affected by use of the usual Road to Health (RTH) chart or the new World Health Organization (WHO) chart format.

Method

Child Health staff in two teaching hospitals and 4 government health centres in Enugu, Nigeria completed a questionnaire on chart use, plotted sample weights on RTH and WHO charts and answered questions on 4 plotted charts, 2 in RTH and 2 WHO format. A factorial design was used so that each respondent rated 4 of 12 permutated charts, presented in one of 3 versions of the questionnaire. The permutatations comprised: 3 different weight trajectories between birth and age 6 months (slow=−2SD fall; average= SD unchanged; fast=1–2 SD rise) towards two attained weights (average=50th centile; small= 2nd–3rd centile) each presented on RTH and WHO format. No respondent viewed the same growth pattern more than once in either format. Responders were asked to rate each the weight pattern shown as slow, steady or rapid and whether it would cause them to increase monitoring or refer out (concern).

Results

Of 233 staff approached, 222 (95%) completed questionnaires. Most were hospital‐based (78%); 32% medical doctors, 13% nutritionists and 54% nurses; 46% had more than 10 years experience. Most respondents used charts often and confidently. Plotting accuracy was generally good and best on the more familiar RTH chart.

Respondents rated 856 charts. Rating of weight gain was generally poor, but varied significantly with size and chart type. On the RTH chart respondents were more likely to recognize slow weight gain in a small (35%) than an average child (19%) and more likely to recognize rapid weight gain in an average (53%) than a small child (18%), but overall their responses were not better than chance (p= 0.052 and 0.15).On the WHO charts slow weight gain was better recognised, though still more in a small (65%; p<0.001) than an average (40%; p=0.002) child. Recognition of fast weight gain was still poor: 53% also rated a rapidly gaining small child as having slow weight gain. In a binary logistic regression model, final size more strongly predicted a slow weight gain rating (OR=2.4; p<0.001) than an actual slow weight gain pattern (OR 1.8; p<0.001). Only a minority felt that any of the weight gain patterns merited concern; this was significantly related to the actual weight gain pattern on WHO, but not on the RTH charts.

Conclusion

Many health staff seemed unable to interpret weight trajectory or recognize slow weight gain and were more influenced by current weight than actual weight gain pattern, though the new WHO format improved recognition.

Support or Funding Information

Ifeyinwa Ezeofor was supported by a Ford Foundation scholarship