Arthritis of the first metatarsophalangeal joint is not always gout: a prospective cohort study in primary care patients.
OBJECTIVE
Arthritis of the first metatarsophalangeal joint has been considered pathognomonic for gout, but it is unknown how frequently other forms of arthritis occur in this joint. The aims were to determine the validity of the general practitioner's clinical diagnosis using joint fluid analysis as the reference test, the prevalence of other diagnoses than gout, and the signs and symptoms that discriminate between gout and non-gout patients.


METHODS
This prospective cohort study comprised primary care patients with monoarthritis of the first metatarsophalangeal joint. After patient recruitment by general practitioners, patients' characteristics were collected by a rheumatologist. Joint fluid was analyzed for the presence of monosodium urate-crystals. If crystals were absent, patients entered a follow-up period of 6 years, or until a definite diagnosis. If during follow-up crystals were identified, the patient was classified as already having gout at baseline assessment.


RESULTS
One hundred and fifty-nine primary care patients were included. At baseline the clinical diagnosis was gout in 98%. The positive and negative predictive values of the diagnosis of gout were 0.79 and 0.75, respectively. After follow-up 77% had gout, 8% had another rheumatic disease, and 15% had a transient unspecified monoarthritis. Gout patients had discriminating signs and symptoms from non-gout patients.


CONCLUSIONS
Gout is an important but certainly not an exclusive cause of arthritis of the first metatarsophalangeal joint.
Department of Rheumatology, Rijnstate Hospital, Arnhem, PO Box 8, 6880 AA, Velp, The Netherlands. Electronic address: lkienhorst@rijnstate.nl.
Laura B E
LB
Kienhorst
Department of Primary and Community Care, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands; Department of Clinical Research, Rijnstate Hospital, Arnhem, PO Box 8, 6880 AA, Velp, The Netherlands.
Hein J E M
HJ
Janssens
Department of Rheumatology, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands.
Jaap
J
Fransen
Department of Primary and Community Care, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands.
Eloy H
EH
van de Lisdonk
Department of Rheumatology, Rijnstate Hospital, Arnhem, PO Box 8, 6880 AA, Velp, The Netherlands.
Matthijs
M
Janssen
D000368:Aged; D001168:Arthritis / Q000175:diagnosis*; D005260:Female; D006073:Gout / Q000175:diagnosis; D006801:Humans; D008297:Male; D008683:Metatarsophalangeal Joint; D008875:Middle Aged; D011320:Primary Health Care; D011446:Prospective Studies; D012216:Rheumatic Diseases / Q000175:diagnosis; D013582:Synovial Fluid / Q000737:chemistry; D014527:Uric Acid / Q000032:analysis
D014527:Uric Acid
Arthritis; First metatarsophalangeal joint; Gout; Monosodium urate-crystals; Synovial fluid