Group A Streptococcal Infections Are Associated With Increased Risk of Pediatric Neuropsychiatric Disorders: A Taiwanese Population-Based Cohort Study.

OBJECTIVE: This study evaluated the association between group A streptococcal (GAS) infections and the risks of developing tic disorders, obsessive-compulsive disorder (OCD), and attention-deficit/hyperactivity disorder (ADHD).
METHODS: We conducted a follow-up cohort study in 2014 using Taiwan's National Health Insurance Research Database. The study cohort consisted of patients younger than 18 years with newly diagnosed GAS infection (ICD-9-CM codes 034 [streptococcal sore throat and scarlet fever] and 482.31 [pneumonia due to Streptococcus, group A]) from 2001 to 2010. All patients having GAS infection codes between 1996 and 2000 were excluded. We assessed the patients' risks of developing tic disorders, OCD, and ADHD (ICD-9-CM codes 300.3 [obsessive-compulsive disorders], 301.4 [obsessive-compulsive personality disorder], 307.2 [tic disorder, unspecified], and 314 [attention deficit disorder]) and compared these risks with those of a control cohort. The primary outcomes of this study were the overall neuropsychiatric disorder occurrence and the occurrence of separate subtypes.
RESULTS: We examined 2,596 patients and 25,960 controls. The incidence of neuropsychiatric disorders in the GAS infection cohort (60.42 per 10,000 person-years) was significantly higher than that in the comparison cohort (49.32 per 10,000 person-years) (hazard ratio [HR] = 1.22; 95% CI, 1.00-1.49). The largest increased risk was for tic disorders (HR = 1.63; 95% CI, 1.02-2.62). Patients hospitalized for GAS infection had a 1.96-fold higher risk of neuropsychiatric disorders than did people without GAS infection (HR = 1.96; 95% CI, 1.23-3.12), and there was no difference in risk between outpatients with GAS infection and people without GAS infection (HR = 1.14; 95% CI, 0.92-1.41). Patients with moderate or high frequencies of GAS infection-related clinic visits had much higher risks of developing a neuropsychiatric disorder and, specifically, tic disorders and ADHD (all P values for trend < .05). These risks were not increased in patients with a low frequency of clinic visits.
CONCLUSIONS: Our results confirmed an association between previous group A streptococcal infection and neuropsychiatric disorders. © Copyright 2016 Physicians Postgraduate Press, Inc.