Improvement in BMI z-score following adenotonsillectomy in adolescents aged 12-18 years: a retrospective cohort study.

BACKGROUND: Characteristics of obstructive sleep apnea (OSA) changes with age. Infants, toddlers and prepubertal children with OSA are usually underweight and may suffer from failure to thrive (FTT). Adenotonsillectomy (T&A) is the first line of treatment for OSA in childhood. In adults OSA is commonly associated with obesity and the metabolic syndrome. The change in body mass index (BMI) in adolescents with OSA following T&A was only sporadically studied. Thus, we peruse to examine the BMI z-score change following T&A in adolescents. METHODS: Clalit Health Services is the largest health care organization in Israel with the largest patient registry (more than 50% of the population). Two hundred and forty two adolescents aged 12-18 who underwent T&A between 2006 and 2015 were identified in the Clalit registry and their characteristics including height and weight were retrieved. The BMI z-score of these adolescents at baseline (up to 3 months prior to T&A) and during the consecutive 3 years after T&A were analyzed and compared. RESULTS: Changes in BMI Z-score were observed to all directions following T&A with overall small increase, not statistically significant (P = 0.26) from a median of 0.79 prior to T&A to a median of 0.835 after it. There was a minimal trend toward BMI z-score reduction in overweight children (n = 74) from 1.508 to 1.48 following T&A (p = NS), and in obese children (n = 33) from 2.288 to 2.000 (P = 0.06, 2 tailed). Interestingly thin individuals (n = 6) increased their BMI z-score following T&A from - 2.4 to - 0.59 (p = 0.046). CONCLUSIONS: Adolescents show variable changes in their BMI z-score following T&A. In this aspect their BMI z-score change is closer to the change seen in adults treated for OSA and not that of young children. The changes observed show a trend toward normalization of the BMI z-score such that overweight children tend to decrease their BMI z-score while thin individuals tend to increase it.