Table 4 Sources of discordance for diagnoses detected by chart review but not case finding algorithms

Coding

Diagnosis not coded due to multi-problem visit

-

1(3)

-

1(7)

13(12)

15(9)

Use of non-specific ICD-9 code

-

-

-

-

13(10)

13(8)

Formatting (e.g. missing decimal place)

-

-

-

-

4(4)

4(2)

Terminology

Alternate terminology used

-

-

-

1(7)

17(16)

18(11)

Access Limitations

Diagnosis record limited to free text fields

3(43)

15(48)

4(40)

6(43)

47(45)

75(45)

Diagnosis confirmed from inaccessible investigations or documents

2(29)

-

-

2(14)

14(13)

18(11)

Not detected from problem list

-

1(3)

-

-

2(2)

3(1)

Data missing after extraction/cleaning

-

6(19)

1(10)

-

30(29)

37(22)

Case Definition

Indicators excluded due to co-existing condition

2(29)

7(23)

-

4(29)

-

13(8)

Insufficient frequency of indicator (e.g. limited visits or labs)

-

-

5(50)

2(14)

-

7(4)

Medications

Medication not included in case definition

1(14)

9(29)

-

7(50)

-

17(10)

Validation Factors

Uncertainty of presence of diagnosis after abstraction

-

-

1(10)

-

-

1(1)

Total Discordant Cases (Chart Review +/CPCSSN-)*

7(100)

31(100)

10(100)

14(100)

105(100)

167(100)