The association between gout and radiographic hand, knee and foot osteoarthritis: a cross-sectional study.
BACKGROUND
Gout is the most common type of inflammatory arthritis and is largely managed in primary care. It classically affects the first metatarsophalangeal joint and distal peripheral joints, whereas the axial joints are typically spared. The reason for this particular distribution is not well understood, however, it has been suggested that osteoarthritis (OA) may be the key factor. One hypothesis is that there is an association between the disease states of gout and OA as the conditions share common risk factors. The objective of this study was to determine whether there is an association between gout and radiographic osteoarthritis (OA).


METHODS
A cross-sectional study was nested within three observational cohorts of people aged ≥ 50 years with hand, knee and foot pain. Participants with gout were identified through primary care medical records and each matched by age and gender to four individuals without gout. The presence and severity of radiographic OA were scored using validated atlases. Conditional logistic regression models were used to examine associations between gout and the presence, frequency and severity of radiographic OA at the hand, knee and foot and adjusted for BMI, diuretic use and site of joint pain.


RESULTS
Fifty-three people with gout were compared to 211 matched subjects without gout. No statistically significant associations were observed between gout and radiographic hand, knee or foot OA. However, individuals with gout had increased odds of having nodal hand OA (aOR 1.46; 95% CI 0.61, 3.50), ≥8 hand joints with moderate to severe OA (aOR 3.57; 95%CI 0.62, 20.45), foot OA (aOR 2.16; 95% CI 0.66, 7.06), ≥3 foot joints affected (aOR 4.00; 95% CI 0.99, 16.10) and ≥1 foot joints with severe OA (aOR 1.46; 95% CI 0.54, 3.94) but decreased odds of tibiofemoral (aOR 0.44; 95% CI 0.15, 1.29) or patellofemoral (aOR 0.70; 95% CI 0.22, 2.22) OA in either knee.


CONCLUSION
There was no association between gout and radiographic OA, however, people with gout appeared to be more likely to have small joint OA and less likely to have large joint OA.