Association of trigger thumb with congenital malformations and developmental milestones among children in a nationwide birth cohort.

Despite extensive research on pediatric trigger thumb, nationwide data on patient characteristics, coexisting birth defects, and development remain limited. This cohort study, using Korean National Health Insurance data, analyzed 1.9 million births (2009-2012) followed to age 6. We identified 10,167 trigger thumb cases and matched them 1:10 by sex and birth year with controls. Baseline features, congenital malformations (International Classification of Disease-10, Q00-Q89), and development at ages 4-6 (Korean Developmental Screening Test) were compared. Conditional logistic regression assessed comorbidity risk, expressed as odds ratio (OR), while generalized estimating equations evaluated the association between trigger thumb and developmental outcomes. The trigger thumb group (average diagnosis age: 31.3 months, 46.6% male) had 32.6% of surgery rate at an average age of 43 months. Trigger thumb group had significantly higher rates of renal agenesis and other reduction defects of kidney (OR 2.95, 95% CI 1.63-5.37), cleft palate (OR 1.79, 95% CI 1.19-2.70), and circulatory system malformations (OR 1.65, 95% CI 1.10-2.49) compared to controls. However, assessment using the Korean Developmental Screening Test revealed no significant delays in development, including gross and fine motor skills. Pediatric trigger thumb is linked to increased congenital malformations but doesn't seem to hinder development. Screening for coexisting conditions and reassuring parents about development are crucial.