A61: Prevalence of Streptococcal Antibodies in Pediatric Non‐Rheumatic Fever Syndromes in Areas of Low Rheumatic Fever Incidence

Background/Purpose: Streptococcus pyogens infect an estimated 5 million children in United States/year. Various syndromes are attributed to elevated Streptococcal antibody titer (SAT) & are treated with prophylactic penicillin therapy (PPT). We hypothesize the elevated SAT has no diagnostic & PPT has no therapeutic significance in pediatric non‐Rheumatic Fever Syndromes in areas of Low Rheumatic Fever Incidence. Methods: A cross‐sectional retrospective electronic chart review was conducted. Patients who met the criteria had tics, chronic pain syndrome (CPS) or joint symptoms as presenting complaints, had streptococcal antibody titers (SAT) performed & were seen by pediatricians in past 5 years at Women's and Children's Hospital . Patients were classified into 3 subgroups. Group 1: 184 presented with joint pain with or without (w/o) swelling, Group 2: 105 presented with tics & Group 3: 324 presented with CPS. Reference lab values were: Antistreptolysin O (ASO);0–1 yr:0–200 IU/mL, 2–12 yrs: 0–240 IU/mL, 13 yrs & older: 0–330 IU/mL & DNAse‐B Ab; 0–6 yrs: Less than 250 U/mL, 7–17yrs:Less than 310 U/mL, 18 yrs & older: Less than 260 U/mL. Elevation of titers by ≥1.5 times for age was considered abnormal for research purposes. Results: Six hundred and thirteen charts were reviewed. Chi‐square test was used to identify proportion of abnormal ASO & DNAse‐B Ab among the 3 diagnostic groups ranged from 26% (JS) to 35% (TICS), and 25.5% to 26.7% respectively; the difference in the abnormal ASO & DNAse‐B Ab in the 3 groups was not significant (ASO p = 0.25, DNAse‐B Ab p = 0.97). An exact Pearson chi‐square test compared the proportion of abnormal ASO & DNAse‐B Ab on patients w/o PPT. The proportion of abnormal results w/o PPT were 5.88% (8/136) & 10.87% (5/46) for ASO & 5.88% (8/136) & 4.35% (2/46) for DNAse‐B Ab, which was not statistically significant (p = 0.74 for ASO, p = 0.32 for DNAse‐B Ab). McNemar's test revealed that the proportion of abnormal ASO results (178/613 = 29.04%) was significantly higher (P‐value = 0.0002) than of DNAse‐B Ab (158/613 = 25.77%). For both ASO & DNAse‐B Ab, odds of abnormal results in males were about 1.73 times higher than in females (CI = 95%, OD = 1.19, 2.51); the highest probability of abnormal results occurred around 129 months. Mean Ab test costs for CPS was $426, JS was $377 & Tics was $556. While 137 patients received PPT, 47 received no therapy; there was no difference in abnormal SAT in both groups at 6 months. Conclusion: In low Rheumatic Fever Incidence areas, abnormal SAT in Pediatric non‐rheumatic fever syndromes have poor diagnostic & therapeutic value; repeat testing adds cost without treatment value.