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Foot pain increases the risk of symptomatic and radiographic knee osteoarthritis: Data from the osteoarthritis initiative
Abstracts / Osteoarthritis and Cartilage 24 (2016) S63eS534
145 FOOT PAIN INCREASES THE RISK OF SYMPTOMATIC RADIOGRAPHIC KNEE OSTEOARTHRITIS: DATA FROM OSTEOARTHRITIS INITIATIVE
AND THE
K.L. Paterson y, J. Kasza z, D.J. Hunter x, R.S. Hinman y, T.V. Wrigley y, H.B. Menz k, G. Peat ¶, K.L. Bennell y. y The Univ. of Melbourne, Melbourne, Australia; z Monash Univ., Melbourne, Australia; x The Univ. of Sydney, Sydney, Australia; k La Trobe Univ., Melbourne, Australia; ¶ Keele Univ., Keele, United Kingdom Purpose: A potential risk factor for knee osteoarthritis (OA) that has received limited attention is foot pain. Like knee OA, foot pain is very common in middle- and older-aged adults and is also highly debilitating. To date, the majority of previous studies investigating foot or knee pain have examined these problems in isolation. However, isolated joint pain is rare, and concurrent foot and knee pain is the most common multi-joint pain presentation. Furthermore, people with both symptomatic knee OA and foot pain report significantly worse general and knee OA specific health outcomes, and poorer physical function, than those
S93
with knee OA but without foot pain. Despite the strong association between pain at these two sites, a temporal sequence has not been evaluated. The aims of this study were to investigate whether foot pain is associated with increased risk of developing (i) persistent knee symptoms and; (ii) symptomatic and radiographic knee OA. Methods: This was a prospective multicentre cohort study using data from the Osteoarthritis Initiative. 3306 participants (1951F (59%), 1355M (51%); mean age 61.3yrs ± 9.2; mean BMI 28.1kg/m2 ± 4.7kg/ m2) who did not have symptomatic radiographic knee OA, but who were at an increased risk of developing the disease, were included. Participants were asked about the presence and laterality of foot pain at baseline, defined as pain, aching or stiffness in the foot and/or ankle on more than half of the days during the past 30 days. The main outcomes were (i) development of persistent knee symptoms, defined as symptomatic pain, aching or stiffness in and around the knee on most days of the month for at least one month in the previous year and; (ii) the development of persistent knee symptoms and radiographic (Kellgren and Lawrence [KL] grade >2) knee OA. People with persistent knee symptoms in one or both knees at baseline were excluded for the first aim, and those with knee symptoms and KL>2 at baseline were excluded for the second aim. Outcomes were obtained during annual visits over the subsequent four years, and were required to be present for at least two consecutive visits during the follow up period. Association between foot pain and the development of study outcomes within the follow-up period were assessed using logistic regression models fitted using generalized estimating equations to account for the correlation between left and right knees within participants. Models were adjusted for baseline age, sex, BMI, knee pain at baseline, race and depression. Results: Of the 2244 participants without symptomatic knee OA at baseline, 13.2% (n ¼ 296) had foot pain in at least one foot. Of these, 7.5% (n ¼ 127) had bilateral foot pain and 5.7% (n ¼ 169) had pain in one foot only. Baseline pain in any foot was associated with a significantly increased risk of developing knee symptoms in the subsequent four years (adjusted OR 1.45, 95% CI 1.09 to 1.93) (Table 1). Additional analyses of foot and knee pain laterality showed that bilateral foot pain had the highest odds for developing knee symptoms (adjusted OR 1.56, 95% CI 1.02 to 2.39), whilst foot pain that was contralateral to the study knee also increased the risk of this outcome (adjusted OR 1.51, 95% CI 1.01 to 2.27). Of the 1020 participants without symptomatic or radiographic knee OA at baseline, 13.0% (n ¼ 133) had foot pain in at least one foot. Of these, 5.4% (n ¼ 55) had bilateral foot pain and 7.6% (n ¼ 78) had pain in one foot only. Baseline pain in any foot was associated with a significantly increased risk of developing both symptomatic and radiographic knee OA in the follow up period (adjusted OR 2.54, 95% CI 1.06 to 6.08) (Table 1). Subgroup analyses based on foot pain laterality suggested larger odds for bilateral foot pain (adjusted OR 4.09, 95% CI 1.42 to 11.75), however few cases developed the outcome. Conclusions: Pain in either or both feet was found to increase the risk of developing both persistent knee symptoms, and symptomatic and radiographic knee OA, within four years in people at risk of the disease. Bilateral foot pain demonstrated the strongest odds for developing these outcomes, although contralateral foot pain was also associated with developing knee symptoms. These findings add support to previous cross-sectional studies demonstrating strong associations between symptoms at the foot and knee, and they provide the first longitudinal evidence of a new, and potentially modifiable, risk factor for the development of knee OA.
Table 1 Risk of developing frequent knee symptoms or symptomatic and radiographic knee OA Risk for frequent knee symptoms
y
Risk for symptomatic ROA P Total Adjusted OR for risk of frequent knee symptoms value number y of knees (95% CI)
Laterality of Total foot pain number of knees
No/infrequent Frequent knee symptoms knee N (%) symptoms N (%)
No pain (ref) 3864 Any side 574 Ipsilateral 162 Contralateral 162 Bilateral 250 OA, osteoarthritis; ROA,
3357 (87.9) 507 (81.5) 1 1738 459 (12.0) 115 (18.5) 1.45 (1.09 to 1.93) 0.011 240 134 (3.5) 28 (4.5) 1.23 (0.79 to 1.91) 0.359 68 129 (3.4) 33 (5.3) 1.51 (1.01 to 2.27) 0.045 68 196 (5.1) 54 (8.7) 1.56 (1.02 to 2.39) 0.041 104 radiographic knee osteoarthritis; OR, odds ratios; CI, confidence intervals.
Adjusted for age, sex, BMI, baseline knee pain, race and depression.
No symptomatic ROA N (%)
Symptomatic Adjusted OR for risk of ROA N (%) symptomatic radiographic knee OA (95% CI)y
1720 (88.1) 232 (11.9) 67 (3.4) 67 (3.4) 98 (5.0)
18 (69.2) 8 (30.8) 1 (3.9) 1 (3.9) 6 (23.1)
2.54 1.27 1.19 4.09
(1.06 (0.16 (0.19 (1.42
to to to to
6.08) 9.82) 7.32) 11.75)
P value
0.036 0.818 0.854 0.009
145 FOOT PAIN INCREASES THE RISK OF SYMPTOMATIC RADIOGRAPHIC KNEE OSTEOARTHRITIS: DATA FROM OSTEOARTHRITIS INITIATIVE
AND THE
K.L. Paterson y, J. Kasza z, D.J. Hunter x, R.S. Hinman y, T.V. Wrigley y, H.B. Menz k, G. Peat ¶, K.L. Bennell y. y The Univ. of Melbourne, Melbourne, Australia; z Monash Univ., Melbourne, Australia; x The Univ. of Sydney, Sydney, Australia; k La Trobe Univ., Melbourne, Australia; ¶ Keele Univ., Keele, United Kingdom Purpose: A potential risk factor for knee osteoarthritis (OA) that has received limited attention is foot pain. Like knee OA, foot pain is very common in middle- and older-aged adults and is also highly debilitating. To date, the majority of previous studies investigating foot or knee pain have examined these problems in isolation. However, isolated joint pain is rare, and concurrent foot and knee pain is the most common multi-joint pain presentation. Furthermore, people with both symptomatic knee OA and foot pain report significantly worse general and knee OA specific health outcomes, and poorer physical function, than those
S93
with knee OA but without foot pain. Despite the strong association between pain at these two sites, a temporal sequence has not been evaluated. The aims of this study were to investigate whether foot pain is associated with increased risk of developing (i) persistent knee symptoms and; (ii) symptomatic and radiographic knee OA. Methods: This was a prospective multicentre cohort study using data from the Osteoarthritis Initiative. 3306 participants (1951F (59%), 1355M (51%); mean age 61.3yrs ± 9.2; mean BMI 28.1kg/m2 ± 4.7kg/ m2) who did not have symptomatic radiographic knee OA, but who were at an increased risk of developing the disease, were included. Participants were asked about the presence and laterality of foot pain at baseline, defined as pain, aching or stiffness in the foot and/or ankle on more than half of the days during the past 30 days. The main outcomes were (i) development of persistent knee symptoms, defined as symptomatic pain, aching or stiffness in and around the knee on most days of the month for at least one month in the previous year and; (ii) the development of persistent knee symptoms and radiographic (Kellgren and Lawrence [KL] grade >2) knee OA. People with persistent knee symptoms in one or both knees at baseline were excluded for the first aim, and those with knee symptoms and KL>2 at baseline were excluded for the second aim. Outcomes were obtained during annual visits over the subsequent four years, and were required to be present for at least two consecutive visits during the follow up period. Association between foot pain and the development of study outcomes within the follow-up period were assessed using logistic regression models fitted using generalized estimating equations to account for the correlation between left and right knees within participants. Models were adjusted for baseline age, sex, BMI, knee pain at baseline, race and depression. Results: Of the 2244 participants without symptomatic knee OA at baseline, 13.2% (n ¼ 296) had foot pain in at least one foot. Of these, 7.5% (n ¼ 127) had bilateral foot pain and 5.7% (n ¼ 169) had pain in one foot only. Baseline pain in any foot was associated with a significantly increased risk of developing knee symptoms in the subsequent four years (adjusted OR 1.45, 95% CI 1.09 to 1.93) (Table 1). Additional analyses of foot and knee pain laterality showed that bilateral foot pain had the highest odds for developing knee symptoms (adjusted OR 1.56, 95% CI 1.02 to 2.39), whilst foot pain that was contralateral to the study knee also increased the risk of this outcome (adjusted OR 1.51, 95% CI 1.01 to 2.27). Of the 1020 participants without symptomatic or radiographic knee OA at baseline, 13.0% (n ¼ 133) had foot pain in at least one foot. Of these, 5.4% (n ¼ 55) had bilateral foot pain and 7.6% (n ¼ 78) had pain in one foot only. Baseline pain in any foot was associated with a significantly increased risk of developing both symptomatic and radiographic knee OA in the follow up period (adjusted OR 2.54, 95% CI 1.06 to 6.08) (Table 1). Subgroup analyses based on foot pain laterality suggested larger odds for bilateral foot pain (adjusted OR 4.09, 95% CI 1.42 to 11.75), however few cases developed the outcome. Conclusions: Pain in either or both feet was found to increase the risk of developing both persistent knee symptoms, and symptomatic and radiographic knee OA, within four years in people at risk of the disease. Bilateral foot pain demonstrated the strongest odds for developing these outcomes, although contralateral foot pain was also associated with developing knee symptoms. These findings add support to previous cross-sectional studies demonstrating strong associations between symptoms at the foot and knee, and they provide the first longitudinal evidence of a new, and potentially modifiable, risk factor for the development of knee OA.
Table 1 Risk of developing frequent knee symptoms or symptomatic and radiographic knee OA Risk for frequent knee symptoms
y
Risk for symptomatic ROA P Total Adjusted OR for risk of frequent knee symptoms value number y of knees (95% CI)
Laterality of Total foot pain number of knees
No/infrequent Frequent knee symptoms knee N (%) symptoms N (%)
No pain (ref) 3864 Any side 574 Ipsilateral 162 Contralateral 162 Bilateral 250 OA, osteoarthritis; ROA,
3357 (87.9) 507 (81.5) 1 1738 459 (12.0) 115 (18.5) 1.45 (1.09 to 1.93) 0.011 240 134 (3.5) 28 (4.5) 1.23 (0.79 to 1.91) 0.359 68 129 (3.4) 33 (5.3) 1.51 (1.01 to 2.27) 0.045 68 196 (5.1) 54 (8.7) 1.56 (1.02 to 2.39) 0.041 104 radiographic knee osteoarthritis; OR, odds ratios; CI, confidence intervals.
Adjusted for age, sex, BMI, baseline knee pain, race and depression.
No symptomatic ROA N (%)
Symptomatic Adjusted OR for risk of ROA N (%) symptomatic radiographic knee OA (95% CI)y
1720 (88.1) 232 (11.9) 67 (3.4) 67 (3.4) 98 (5.0)
18 (69.2) 8 (30.8) 1 (3.9) 1 (3.9) 6 (23.1)
2.54 1.27 1.19 4.09
(1.06 (0.16 (0.19 (1.42
to to to to
6.08) 9.82) 7.32) 11.75)
P value
0.036 0.818 0.854 0.009