Table 1

Studies giving a PPV of ≥5% in one or more strata of rectal bleeding for colorectal cancer.

							Stratification with PPV ≥5%
Study and NOQAS star rating	Type	Data source	Follow-up	Age, years	Sex	Symptom	Sex	Age, years	Number with symptom	PPV, % (95% CI)
Jones et al, 200712 (9 stars)	Retrospective cohort	Routinely recorded computer codes	3 years	≥15	All	Rectal bleeding computer codes	M	75–84	633	7.7 (5.8 to 10.1)

								≥85	157	5.1 (2.2 to 9.8)

							F	75–84	930	7.2 (5.6 to 9.1)

Parker et al, 200713 (7 stars)	Retrospective cohort	Routinely recorded computer codes	2 years	≥25	All	First ever consultation with rectal bleeding computer code	M+F	75–84	Number with cancer 173	5.5 (4.7 to 6.3)

Lawrenson et al, 200614 (9 stars)	Retrospective cohort	Routinely recorded computer codes	1 year	40–89	All	Rectal bleeding computer codes	M	60–69	Not given	6.0^a

								70–79	Not given	7.7^a

								80–89	Not given	9.1^a

Wauters et al, 200015 (6 stars)	Retrospective cohort	Routinely registered	18–30 months	All	All	Cases of rectal bleeding	M+F	60–69	71	11.2 (5.0 to 21.0)

								70–79	66	21.2 (12.0 to 33.0)

								≥80	51	5.8 (1.2 to 16.2)

Du Toit et al, 200616 (6 stars)	Prospective cohort	Specifically registered	Not given	≥45	All	New onset rectal bleeding	M+F	65–74	63	9.5 (4.4 to 19.3)

								≥75	76	7.9 (3.7 to 16.2)

Heintze et al, 200517 (7 stars)	Prospective cohort	Specifically registered	Not given	≥15	All	Cases rectal bleeding	M+F	≥50	268	5.6 (3.4 to 9.0)

Ellis and Thompson, 200518 (6 stars)	Prospective cohort	Specifically registered	18 months	>34	All	Primary complaint rectal bleeding	M+F	≥60	155	5.2 (2.6 to 9.9)

Nørrelund and Nørrelund, 199619 (3 stars)	Prospective cohort	Specifically registered	22–57 months	≥40	All	First episode or change in rectal bleeding pattern	M+F	≥40	364	14.8 (11.6 to 18.9)

Metcalf et al, 199620 (5 stars)	Prospective cohort	Specifically registered	Not given	≥40	All	Rectal bleeding of recent onset	M+F	≥40	99	8.1 (4.2 to 15.1)

Mant et al, 198922 (5 stars)	Prospective cohort	Specifically registered	Not given	≥40	All	Rectal bleeding <6 months onset	M+F	≥40	145	11.0 (6.9 to 17.2)

Fijten et al, 199521 (6 stars)	Prospective cohort	Specifically registered	Mean 20 months SD 5 months	18–75	All	Overt rectal bleeding reason for encounter or history of rectal blood loss visible to the patient in the previous 3 months	M	18–75	118	5.9 (2.9 to 11.7)

							M+F	60–75	40	20.0 (10.5 to 34.8)

↵a Not possible to calculate confidence intervals (author contacted, original data not available). F = female. M = male. NOQAS = Newcastle-Ottawa Quality Assessment Scales. PPV = positive predictive value. SD = standard deviation.