Cognitive outcome in congenital central hypothyroidism: a systematic review with meta-analysis of individual patient data.

Objective: To provide an overview of cognitive and motor outcome, and quality of life (QoL) in patients with congenital central hypothyroidism (CH-C).
Design: Systematic review with individual patient data (IPD) meta-analysis.
Methods: OVID MEDLINE, EMBASE and PsycInfo were searched from inception to June 11th, 2019. Studies in patients with CH-C, either isolated or with multiple pituitary hormone deficiency (MPHD), were included if CH-C patients could be separated from any additional patient groups. Primary outcomes were full-scale intelligence quotient (FSIQ) and motor outcome; secondary outcome was QoL. Following data-extraction, one-stage IPD meta-analysis was performed, fitting a linear mixed model with FSIQ as dependent variable. Random intercepts were fitted for each study.
Results: Six studies measuring FSIQ were eligible for meta-analysis, comprising 30 CH-C patients (20 males; 27 MPHD patients). FSIQ range was wide (64-123). Mean weighted FSIQ was 97 (95% CI: 88-105). Twenty-seven percent had an FSIQ below 85 (≥1 s.d. below norm score), and 10% below 70 (≥2 s.d. below norm score). There was no significant association between FSIQ and sex or age. Age at treatment initiation was available from three studies only, thus impeding a reliable analysis of this parameter. Motor outcome and QoL were each studied in one study; no quantitative analyses could be performed for these outcomes.
Conclusion: A wide range in FSIQ scores was observed in CH-C patients. Results should be interpreted with caution, because included patients mainly had MPHD and age at treatment initiation was unknown for the majority of patients.