Sensitivity and Specificity of Visual Clinical Assessment as Compared to WHO 2006 Standard and NCHS 1977 Reference in Measuring the Growth Status of Malaysian Infants

Abstract

Objective: To study the validity of the visual clinical assessment of weight relative to length and length relative to age as compared to the World Health Organization (WHO) 2006 standard and National Center for Health Statistics (NCHS) 1977 reference in asssessing the physical growth of children younger than 1 year.

Materials and Methods: A prospective cohort study was carried out among 684 infants attending goverment health clinics in 2 states in Malaysia. Body weight, length, and clinical assessment were measured on the same day for 9 visits, scheduled every month until 6 months of age and every 2 months until 12 months of age. All of the 3 z-scores for weight for age (WAZ), length for age (HAZ), and weight for length (WHZ) were calculated using WHO Anthro for Personal Computers software.

Results: The average sensitivity and specificity for the visual clinical assessment for the detection of thinness were higher using the WHO 2006 standard as compared with using NCHS 1977. However, the overall sensitivity of the visual clinical assessment for the detection of thin and lean children was lower from 1 month of age until a year as compared with the WHO 2006 standard and NCHS 1977 reference. The positive predictive value (PPV) for the visual clinical assessment versus the WHO 2006 standard was almost doubled as compared with the PPV of visual clinical assessment versus the NCHS 1977 reference. The overall average sensitivity, specificity, PPV, and negative predictive value for the detection of stunting was higher for visual clinical assessment versus the WHO 2006 standard as compared with visual clinical assessment versus the NCHS 1977 reference.

Conclusion: The sensitivity and specificity of visual clinical assessment for the detection of wasting and stunting among infants are better for the WHO 2006 standard than the NCHS 1977 reference.

Key words::

• validity
• NCHS 1977 growth reference
• WHO 2006 growth standard
• visual clinical assessment
• nutritional status

ACKNOWLEDGMENTS

This study was financially supported by the Ministry of Health, Malaysia. We would like to thank the Director General of Health, Ministry of Health Malaysia, for his permission to publish this article. We are also indebted to all the technical committee members, enumerators, and state coordinators (Ms Zahariah Mohd Nordin, Ms Rafidah Yusof, and Ms Norliza Zainal Abidin) for their support and commitment to this study. Finally, we would like to thank the parents who agreed to participate in this study.

Table 1. Characteristics of the Respondents at Baseline

Table 2. Nutritional Status of Infants Based on WAZ, WHZ, and HAZ Using the WHO 2006 Standard and NCHS 1977 Reference at Several Points of Visits

Table 3. SN, SP, PPV, NPV, and Likelihood Ratio for the Detection of Thin and Lean by Clinical Assessment as Compared with the WHO 2006 Standard and NCHS 1977 Reference at Several Visits

Table 4. SN, SP, PPV, NPV, and Likelihood Ratio for the Detection of Stunting by Clinical Assessment as Compared with the WHO 2006 Standard and the NCHS 1977 Reference at Several Visits

Notes

Author disclosures: The authors declare that they have no conflict of interests. There is also no personal financial interest in the work.