1. Dipstick Screening for Urinary Tract Infection in Febrile Infants Journal Club Tuesday 15 th July 2014 Charlotte Elder

3. Background SBI occurs in 10-15% 1-90 day olds UTI commonest cause SBI Utah –Neonates – FSS and empirical Abx –>28/7 – screen tests and ? admit NICE –Infants <3/12 – urine testing –Urgent M+C for infants <3/12 –Dipstick for children >3yrs

4. SCH guideline (7.1) “Children younger than 2 years of age: –Urgent microscopy and culture preferred method for diagnosing UTI –Dipstick analysis may be unreliable”

5. Nitrites –Urinary micro-organisms reduce nitrate to nitrite –Nitrate needs to be in contact with bacteria for “some time” –Not all bacteria –Too quick in under 2s? Leucocytes (LE) –LE enzyme contained in WBC –UTI not the only cause of pyuria Evidence base?

6. Systematic review 6 studies Dipstick signif less good in < 2yrs LR –+LR 38.5 vs 7.6 –-LR 0.13 vs 0.34 Mori et al. Acta paediatrica 2010;99:581-584

7. The Clinical Question PopulationChildren less than 2 years with suspected UTI InterventionDipstick urine testing or urine microscopy ComparisonUrine culture OutcomeAccurate diagnosis of UTI

9. Aim Comparing performance of urine dipstick alone with urine microscopy and with both tests combined as a screen for UTI in febrile infants aged 1 - 90 days.

10. Methods Retrospective observational study July 2004 – December 2011 (7.5 yrs) Multi-centre (23 hospitals) Same diagnostic equipment and database Patients identified from database –Febrile infants and age –Reason for visit –Admitting diagnosis –ICD-9 and coding

11. Methods Age 1-90 days Catheterised urine – 10mls –Dipstick –Microscopy of centrifuged urine –Culture Medical records r/v if UTI but dipstick negative for outcome (29-90 days)

12. Definitions - cultures Positive for UTI –≥1 pathogen –≥50,000 CFU/ml (half the “classic” definition) Negative for UTI –No bacterial growth –Growth of contaminant only <10 5 CFU/ml common skin GU flora –Multiple bacteria each <10 5 CFU/ml Equivocal –Urine pathogens 10,000-49,000 CFU/ml –Excluded from analysis

13. Definitions – dip/micro/combo Positive for UTI - dipstick –LE positive –Nitrite positive –≥ trace Positive for UTI - microscopy –>10 WBC per hpf –≥ 1 bacteria per hpf Positive UTI – combined –Positive dipstick OR –Positive microscopy

14. Results

15. Study flow chart

16. Results 6394 febrile infants 770 UTI (12%)5624 no UTI 1745 (27%) neonates 4649 (73%) 29-90 days old 6394 febrile infants

18. p = <0.001 Sensitivity = true positives

19. p = <0.001 Specificity = true negatives

20. p = <0.001

25. Example Prevalence in 29-90 day old infants = 11.9% 1000 febrile infants –119 culture positive UTI –Dipstick alone 90.4% true positive pick up (108/119) – 9.6% false negative 6.2% false positive rate (55 of 881) –Combined urinalysis 94.8% true positive pick up (113/119) – 5.2% false negative 10.9% false positive rate (96 of 881) 8 treated who don’t have UTI for every 1 infant missed

26. Critical appraisal Does the study address a clearly focused question? Did the study use valid methods to address the Qu? Are the valid results of the study important? Are the valid, important results applicable to our local population? Were all clinically important outcomes considered? Are the benefits worth the harms/risks/costs?

27. Summary and Conclusion Good to rule out UTI CLINICAL BOTTOM LINE Can dip infants’ urine?