Optimising the use of electronic health records to estimate the incidence of rheumatoid arthritis in primary care: what information is hidden in free text?

Table 3 List of the most frequent Read codes used in conjunction with free text containing keywords

Read code	Frequency	Overall rank	Rheumatoid arthritis rank	Inflammatory arthritis rank	Positive RhF test rank	Synovitis rank
Letter from specialist	2576	1	1	1	1	1
Seen in rheumatology clinic	1979	2	2	2	2	2
Incoming mail NOS	770	3	4	3	4	3
Rheumatoid factor	592	4	3	10	3
Rheumatoid arthritis	546	5	6	11	5	6
Patient reviewed	482	6	9	5	7	5
Pain in joint - arthralgia	467	7	11	6	8	4
Had a chat to patient	345	8		17	6	7
Rheumatoid factor screening test	313	9	5		9
Incoming mail	253	10	13	9	13	8
History / symptoms	239	11	8		10
Seen by rheumatologist	215	12	14	8	15	9
Communication from:	208	13	12	19	14	10
Arthritis	197	14		4	11	12
Advice to patient - subject	191	15	7		20
MED3 - doctor’s statement	186	16	10	7	18
Telephone encounter	169	17	18	16	12
Arthralgia of unspecified site	90	18			17	13
Hand pain	90	19			16	14
Suspected condition	67	20	16	12
Nursing care blood sample taken	59	21			19
Seen in hospital out-pat.	56	22	20			17
R.A. latex test	53	23	15
Incoming mail processing	46	24		14		15
Serum rheumatoid antigen level	44	25	17
Letter from consultant	34	26	19
Synovitis or tenosynovitis NOS	30	27				11
Synovitis and tenosynovitis	25	28				16
Arthropathy NOS	21	29		13
Examination of patient	21	30				18
Wrist joint pain	18	31				19
Seen in orthopaedic clinic	18	32		15
Arthropathy NOS	17	33				20
MED3 issued to patient	15	34		18
Seronegative arthritis	13	35		20

ISSN: 1471-2288