Worsening of pain and function over 5 years in individuals with 'early' OA is related to structural damage: data from the Osteoarthritis Initiative and CHECK (Cohort Hip & Cohort Knee) study.
OBJECTIVE
To analyse the relation of joint damage on evolution of pain and physical functioning in two different cohorts of early phase of osteoarthritis (OA): Osteoarthritis Initiative (OAI) and Cohort Hip & Cohort Knee study (CHECK).


METHODS
Longitudinal data of 4-5 years follow-up (= medium term) of CHECK study and OAI were used. The Western Ontario and McMaster Universities of Osteoarthritis Index (WOMAC) was used to measure pain and physical functioning. For comparison with CHECK a subgroup of the OAI Incidence cohort was selected, Generalised estimating equations were used and all models were adjusted for gender, Body Mass Index, age, amount of working hours, racial background and hip pain at baseline. Finally, an interaction term was added to assess a possible differential effect of radiological progression on evolution of pain and function in the two cohorts.


RESULTS
At baseline, CHECK had less radiographic OA (K&L ≥2) compared with the OAI Incidence subgroup, but at follow-up CHECK had more radiographic change (51% vs 15% ≥1 K&L point increase; p<0.001). Over 4 years of follow-up, evolution of pain and physical functioning remained fairly stable in both cohorts, however, at different levels, OAI participants had less pain and less problems with physical functioning compared to CHECK participants. Both cohorts showed the same negative effect of rapid radiological change (K&L change of 2 points) on pain and physical function.


CONCLUSIONS
In participants with 'early symptomatic OA' rapid radiological change (change of ≥2 grades of K&L in 4 or 5 years) is related to worsening of pain and function.
Department of Rheumatology & Clinical Immunology, University Medical Center Utrecht, Utrecht, The Netherlands.
Janet
J
Wesseling
Department of General Practice, Erasmus MC-University Medical Center Rotterdam, Rotterdam, The Netherlands Department of Orthopedics, Erasmus MC-University Medical Center Rotterdam, The Netherlands.
Sita M A
SM
Bierma-Zeinstra
Department of Rheumatology and Department of Clinical Epidemiology, Leiden University Medical Centre, Leiden, The Netherlands.
Margreet
M
Kloppenburg
Department of Rheumatology, Wilhelmina Hospital Assen, Assen, The Netherlands.
Rik
R
Meijer
Department of Rheumatology & Clinical Immunology, University Medical Center Utrecht, Utrecht, The Netherlands.
Johannes W J
JW
Bijlsma
D000368:Aged; D015331:Cohort Studies; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000150:complications* / Q000000981:diagnostic imaging / Q000473:pathology*; D010146:Pain / Q000209:etiology; D011859:Radiography
Epidemiology; Knee Osteoarthritis; Osteoarthritis