Case records of children and adolescents between 5-18 years of age presenting to the pediatric endocrine clinic of our hospital with short stature from January 2015 to December 2018 were reviewed after institutional ethics committee approval. Height was measured using a portable stadiometer (Model 213, Seca scale, Germany) up to an accuracy of 1 mm. Subjects were asked to stand on the platform with heels together, toes apart and back of the occiput, shoulder blades, buttocks and heels in contact with the backboard. Readings were taken in triplicate and averaged. The stadiometer was calibrated daily with Seca Calibration Rod. Weight was measured using Seca Scale till 100 grams which was calibrated daily.

The anthropometric parameters were converted to Z-score using WHO Anthroplus software, and macros derived from IAP 2007, and IAP 2015 growth charts. Children with height Z-score less than -2 as per WHO criteria were evaluated for etiology of short stature as per institutional protocol. The work-up included a comprehensive clinical examination and screening tests (complete blood count, alanine aspartate transferase, creatinine, free T4, thyroid stimulating hormone, tissue transglutaminase antibody, and serum electrolytes) in all and further work-up as required (karyotype in girls, growth hormone stimulation test, genetic tests, venous blood gas, etc.). Subjects with normal work-up and growth velocity over a six-month period were diagnosed as physiological short stature. Children short by WHO but normal by IAP 2007 and 2015 criteria were excluded from the study if their weight SDS was below -2 as per the IAP 2007 or 2015, indicating the need for evaluation irrespective of height. A sample size of 340 was required considering a prevalence of pathological short stature of 33% [10], 95% confidence and a standard error of 0.05.

Data were analyzed using the IBM Statistical Package for Social Sciences (SPSS version 25.0, SPSS, Inc) for Macintosh, and expressed as mean (standard deviation) and frequency (percentage). Sensitivity, specificity, positive predictive value, negative predictive values and likelihood ratio of IAP 2015, IAP 2007 criteria were calculated. P value less than 0.05 was considered significant.

Seven hundred and forty children (377 boys) presented with a concern of short stature to our clinic during the study period. Forty children with incomplete data and 190 with normal stature were excluded. The WHO, IAP 2007 and IAP 2015 criteria labelled 510 (72.6%), 410 (58.2%) and 331 (47%) subjects short, respectively. Ten subjects labelled short by WHO, and normal by IAP 2007 and IAP 2015 were excluded as their weight z-score was below -2 by IAP 2007 or IAP 2015 criteria. The final analysis was performed in 500 subjects (266 boys) with mean (SD) age of 11.8 (3.1) years. The height z-score was above -2 in 90 (18%), between -2 to -3 in 245 (49%), and below -2 in 165 (33%) as per IAP 2015 criteria.

A pathological cause of short stature was identified in 218 (43.6%) and included celiac disease (83, 16.6%), growth hormone deficiency (78, 15.6%), hypothyroidism (33, 6.6%), Turner syndrome (8, 1.6%), chronic illness (8, 1.6%) and other syndromes (8, 1.6%). Among the 218 subjects, 216 (99%) were short by IAP 2015 and 178 (81.6%) by IAP 2007 criteria. Ninety subjects short by WHO criteria had normal stature as per IAP 2015. A pathological cause was identified in 38 of the 79 subjects (48.1%) short as per both WHO and IAP 2015 but normal by the IAP 2007 criteria. The sensitivity, specificity, negative predictive value and positive predictive value specificity of IAP 2015 and 2007 in identifying pathological short stature are shown in Table I. Identification of one child with pathological cause would have required evaluation of 45 subjects short by WHO but normal by IAP 2015.