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Systematic review and meta-analysis on diagnostic accuracy of signs & symptoms predicting uncomplicated urinary tract infection in women Giesen LGM Erasmus student Sept – Dec 2009 RCSI, Dublin Cousins G, Dimitrov BD , Van de Laar FA, Fahey T
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Page 1: Systematic review and meta-analysis on diagnostic accuracy of signs & symptoms predicting uncomplicated urinary tract infection in women Giesen LGM Erasmus.

Systematic review and meta-analysis on diagnostic accuracy of signs & symptoms

predicting uncomplicated urinary tract infection in women

Giesen LGMErasmus student Sept – Dec 2009 RCSI, Dublin

Cousins G, Dimitrov BD , Van de Laar FA, Fahey T

Page 2: Systematic review and meta-analysis on diagnostic accuracy of signs & symptoms predicting uncomplicated urinary tract infection in women Giesen LGM Erasmus.

Outline

• Background/ Rationale

• Methods

• Results

• Conclusion

Page 3: Systematic review and meta-analysis on diagnostic accuracy of signs & symptoms predicting uncomplicated urinary tract infection in women Giesen LGM Erasmus.

Background

• Prevalence– 5% asymptomatic– 50% symptomatic

• Pathogens

• Reference standard– Midstream urine culture– Thresholds >10², >10³, >105 CFU/ml

Page 4: Systematic review and meta-analysis on diagnostic accuracy of signs & symptoms predicting uncomplicated urinary tract infection in women Giesen LGM Erasmus.

Diagnosis UTI

Diagnosis

Dipstick testing Culture urineSigns & symptoms

Page 5: Systematic review and meta-analysis on diagnostic accuracy of signs & symptoms predicting uncomplicated urinary tract infection in women Giesen LGM Erasmus.

Diagnosis UTI

Diagnosis

Dipstick testing Culture urineSigns & symptoms

Page 6: Systematic review and meta-analysis on diagnostic accuracy of signs & symptoms predicting uncomplicated urinary tract infection in women Giesen LGM Erasmus.

Rationale

• Bent 2002– Meta-analysis of 9 studies

– Reference standard > 104 CFU/ml

– Significant symptoms & signs

• What can we add?– 9 additional studies

– European guidelines

– Consideration of heterogeneity

Page 7: Systematic review and meta-analysis on diagnostic accuracy of signs & symptoms predicting uncomplicated urinary tract infection in women Giesen LGM Erasmus.

Diagnostic accuracy signs & symptoms

Reference test :

Urine culture

> 10² CFU/ml

>10³ CFU/ml

>105 CFU/ml

Signs & symptoms

Dysuria

Frequency

Urgency

Hematuria

Fever

Flank pain

Absence vaginal discharge

& irritation

Page 8: Systematic review and meta-analysis on diagnostic accuracy of signs & symptoms predicting uncomplicated urinary tract infection in women Giesen LGM Erasmus.

Participants Healthy women with symptoms of UTI

Setting Primary care

Index test Signs & symptoms

Reference test Urine culture (> 10², >103, >105 CFU/ml)

Outcome measure 2x2 tables

Methods – Identification of studies

Page 9: Systematic review and meta-analysis on diagnostic accuracy of signs & symptoms predicting uncomplicated urinary tract infection in women Giesen LGM Erasmus.

Methods

• Quality assessment (QUADAS)

• Meta-analysis 1. Derivation of summary statistics of each study (2x2

tables)

2. Pooling the summary statistics across studies

3. Examine the pattern of variability (heterogeneity) observed in the results

Page 10: Systematic review and meta-analysis on diagnostic accuracy of signs & symptoms predicting uncomplicated urinary tract infection in women Giesen LGM Erasmus.

Derivation of summary statistics

Little (2006)      

  UTI No UTI Total

Frequency 185 94 279

No frequency 69 60 129

Total 254 154 408

Sensitivity:

185/254 = 72.8%

Specificity: 60/154 = 39.0%

+ LR = sens/ (1- spec) =

72.8/ (1-39.0) = 1.19

Page 11: Systematic review and meta-analysis on diagnostic accuracy of signs & symptoms predicting uncomplicated urinary tract infection in women Giesen LGM Erasmus.

Results: 16 studiesQuality assessment

Time period index and reference test

Blinding

Contamination reported

Pt selected consecutively

Data included 95%CI

Page 12: Systematic review and meta-analysis on diagnostic accuracy of signs & symptoms predicting uncomplicated urinary tract infection in women Giesen LGM Erasmus.

Results: Meta-analysis (> 102)

Symptom (# studies) Sens (95%CI) Spec (95%CI) + LR (95%CI)

Frequency (13) 0.88 (0.83-0.92) 0.20 (0.14-0.28) 1.10 (1.04-1.16)

Dysuria (14) 0.80 (0.74-0.86) 0.38 (0.31-0.46) 1.30 (1.20-1.41)

Hematuria (7) 0.25 (0.21-0.29) 0.85 (0.81-0.89) 1.72 (1.30-2.27)

Nocturia (6) 0.59 (0.50-0.68) 0.55 (0.49-0.61) 1.30 (1.08-1.56)

Urgency (9) 0.67 (0.52-0.80) 0.45 (0.31-0.60) 1.22 (1.11-1.34)

Vaginal discharge (6) 0.15 (0.08-0.26) 0.77 (0.62-0.88) 0.65 (0.51-0.83)

Page 13: Systematic review and meta-analysis on diagnostic accuracy of signs & symptoms predicting uncomplicated urinary tract infection in women Giesen LGM Erasmus.

Pretest & posttest probability

Pretest Probability =

50%

Posttest Probability

Frequency LR+ = 1.10

Hematuria LR+ = 1.72

Dysuria LR+ = 1.30

Nocturia LR+ = 1.30

Urgency LR+ = 1.22

Vaginal discharge LR+ = 0.65

52,4%

56.5%

63.2%

55.0%

39.4%

56.5%

Page 14: Systematic review and meta-analysis on diagnostic accuracy of signs & symptoms predicting uncomplicated urinary tract infection in women Giesen LGM Erasmus.

Heterogeneity - threshold effect (> 102)Symptom (# studies) Correlation P-value Present

Frequency (13) 0.698 0.008 X

Dysuria (14) 0.679 0.008 X

Hematuria (7) -0.714 0.071

Nocturia (6) 0.257 0.623

Urgency (9) 0.933 0.000 X

Vaginal discharge (6) 1.000 0.000 X

Page 15: Systematic review and meta-analysis on diagnostic accuracy of signs & symptoms predicting uncomplicated urinary tract infection in women Giesen LGM Erasmus.

Heterogeneity frequency - threshold effect

Frequency (# studies) Correlation P-value Present

> 102 CFU/ml (13) 0.698 0.008 X

> 103 CFU/ml (11) 0.673 0.023 X

> 105 CFU/ml (6)0.486 0.329

Page 16: Systematic review and meta-analysis on diagnostic accuracy of signs & symptoms predicting uncomplicated urinary tract infection in women Giesen LGM Erasmus.

Heterogeneity 102 CFU/ml 103 CFU/ml

Figures: sensitivity frequency

I-square = 84.9% I-square = 85.2% I-square = 68.1%

105 CFU/ml

Page 17: Systematic review and meta-analysis on diagnostic accuracy of signs & symptoms predicting uncomplicated urinary tract infection in women Giesen LGM Erasmus.

Conclusions

• 5 symptoms increase the probability of UTI when

present (frequency/ dysuria/ hematuria/ nocturia/

urgency)– Vaginal discharge decreased probability of UTI

• However only modest ability to ‘rule in’ or ‘rule out’ UTI– High pre-test probability

Page 18: Systematic review and meta-analysis on diagnostic accuracy of signs & symptoms predicting uncomplicated urinary tract infection in women Giesen LGM Erasmus.

Conclusions

• Importance of considering heterogeneity– Variations in diagnostic threshold– Patient selection/ setting

• Future directions– Combinations of symptoms – clinical prediction rule– Severitiy of symptoms


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