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Predictive value of symptoms, signs and diagnostic tests in patients presenting with rectal bleeding in primary care: diagnostic accuracy systematic review in relation to colorectal cancer Olde Bekkink M, McCowan C, Falk G, Teljeur C, Van de Laar F, Fahey T. Marleen Olde Bekkink
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Predictive value of symptoms, signs and diagnostic tests in patients presenting with rectal bleeding in primary care: diagnostic accuracy systematic review in relation to colorectal cancerOlde Bekkink M, McCowan C, Falk G,Teljeur C, Van de Laar F,Fahey T. Marleen Olde Bekkink Erasmus student, clinical research fellow Dept of General Practice Radboud University Nijmegen Medical Centre, the Netherlands 27th February 2009
General population: < 1 per 10001 people 1st selection by patient General practice: 2-11 per 1001 patients 2nd selection by GP Secondary care: 36 per 1001referred patients Background Incidence of CRC in patients with rectal bleeding *1. Fijten GH et al. 1994 *Mant A. et al. 1988 Olde Bekkink M, McCowan C, Falk G, Teljeur C, Van de Laar F,Fahey T. 27-02-09 2
Methods - Study protocol • Inclusion criteria Population * Patients recruited from primary care population * Rectal bleeding and associated symptoms Study design * Observational cohort studies Reference standard and follow up *Colonoscopy *Flexible/ rigid sigmoidoscopy (and barium enema) *Questionnaire/ follow up only Outcome measures * Data must allow construction of 2x2 tables Olde Bekkink M, McCowan C, Falk G, Teljeur C, Van de Laar F,Fahey T. 27-02-09 3
Potentially relevant citations (n=1534) Excluded after scanning of citation or abstract (n=1470) Full text retrieved (n=64) Excluded (n=56) Reason for exclusion: Setting not in general practice (n = 23) Screening study (n = 5) Case control study (n = 5) Data not extractable from 2x2 table (n = 15) Other (n=8) Included studies (n=8) Methods – Inclusion of articles Olde Bekkink M, McCowan C, Falk G, Teljeur C, Van de Laar F,Fahey T. 27-02-09 4
Methods – Characteristics of the included studies • No of patients included: 2323 • Prior CRC Weighted average: 7.0 % Median : 8.1 % Eight included studies (1988 - 2006) Olde Bekkink M, McCowan C, Falk G, Teljeur C, Van de Laar F,Fahey T. 27-02-09 5
Methods – Quality assessment Olde Bekkink M, McCowan C, Falk G, Teljeur C, Van de Laar F,Fahey T. 27-02-09 6
Methods- Data extraction • Extraction in 2x2 tables to calculate LR+ Metcalf 1996 prior 8/99 Olde Bekkink M, McCowan C, Falk G, Teljeur C, Van de Laar F,Fahey T. 27-02-09 7
Results- Pooled positive likelihood ratios Olde Bekkink M, McCowan C, Falk G, Teljeur C, Van de Laar F,Fahey T. 27-02-09 8
Limitations of sub studies Reference standard ≠ gold standard Limitations of the review Internal validity Reference categories External validity Incidence of colorectal cancer Discussion Edited image (MO) Original: Mayo Foundation for Medical Education and Research Olde Bekkink M, McCowan C, Falk G, Teljeur C, Van de Laar F,Fahey T. 27-02-09 9
Conclusion Value of the review • Predictive value of rectal bleeding low-moderate • Alarm symptoms yield only moderate likelihood ratios • Further studies required calculating independent values using a multivariable analysis Olde Bekkink M, McCowan C, Falk G, Teljeur C, Van de Laar F,Fahey T. 27-02-09 10
Questions Thank you!