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.