FRI0410 PREVALENCE AND FACTORS ASSOCIATED WITH CHRONIC PAIN WITH NEUROPATHIC CHARACTERISTICS IN PATIENTS WITH KNEE OSTEOARTHRITIS IN CAMEROON, SUB-SAHARAN AFRICA
Authors: F. Kemta Lekpa, A. Tidjong Kamkui, D. S. Nsagha, H. Namme Luma, S. P. Choukem
Journal: Annals of the Rheumatic Diseases (2020)

Background: Recent studies suggest that pain in osteoarthritis (OA) is not only nociceptive, but also has neuropathic characteristics (1). To our knowledge, no study has been carried out in sub-Saharan Africa to assess the neuropathic pain associated with knee OA. Objectives: To determine the prevalence of chronic pain with neuropathic characteristics and associated factors in patients with knee OA in Cameroon. Methods: We performed a cross-sectional study at the Douala General Hospital from December 2018 to April 2019. Patients over the age of 21 with a diagnosis of knee OA (ARA, 1986; Kellgren–Lawrence radiographic grading ≥ 2) were included. The intensity of the pain was measured using the visual analog scale. Neuropathic pain was detected using the DN4 questionnaire with a cut-off at DN4 ≥ 4 (2) and functional impairment assessed using the Lequesne algofunctional index. Logistic regression analysis was used to assess the association between patients’ characteristics and DN4. The p &lt;0.05 was considered significant. Results: We included 151 patients (120 women) with knee OA, mean age at 59.8 ± 12.8 years (31 to 86) years, with a mean duration of knee OA at 38 ± 44.9 months and a mean BMI at 30.4 ± 6.2 kg/m2. The mean DN4 score was 2.5±2. It was higher in women compared to men (2.7 ± 2 vs. 1.9 ± 1.7; p = 0.04). Tingling (58.9%) was the most frequently encountered item in the DN4 questionnaire (Table 1). A DN4 ≥ 4 was found in 41 patients (27.1%). Patients with neuropathic pain (DN4 ≥ 4) were older (63.7 ± 10.6 years vs. 58.4 ± 13.2; p = 0.02) and had higher VAS pain (6.17 ± 1.6 vs. 5.02 ± 1.5; p &lt; 0.01) than patients without neuropathic pain (DN4 &lt; 4). In multivariate analysis, only the intensity of pain ≥ 70mm (OR = 2.1, 95%CI: 1.1–5.5; p = 0.02) and a Lequesne index ≥ 11 (OR = 2.4, 95% CI: 1.1–6.7; p = 0.04) were associated with neuropathic pain. Patient’s age at diagnosis, sex, occupation, monthly income, radiological characteristics, BMI, joint effusion, duration of illness, and the existence of comorbidities such as low back pain, diabetes, or hypertension were not associated with the diagnosis of neuropathic pain (p&lt;0.05). Table 1. Frequency of items in the DN4 questionnaire DN4 items Frequency, n (%) Interview of the patient Question 1 Burning 58 (38.4) Painful cold 8 (5.3) Electric shocks 50 (33.1) Question 2 Tingling 62 (41) Pins and needles 89 (58.9) Numbness 68 (45) Itching 14 (9.2) Examination of the patient Question 3 Hypoesthesia to touch 16 (10.6) Hypoesthesia to pinprick 8 (5.3) Question 4 Brushing 22 (14.5) Table 2. Univariate and multivariate logistic regression analysis of factors associated with neuropathic pain Variables CateLgory Unadjusted OR 95% CI p Adjusted OR 95% CI P Age, year &lt;40 0.2 0-2.2 0.37 40-65 1.4 0.1-2.9 0.43 &gt;65 0.5 0.2-1.1 0.14 Sex Female 2.2 0.7-6.2 0.18 Male 1 Occupation Student 1.3 0.1-15.3 1 Employed 3.1 1.3-6.9 0.008 1.4 0.3-4.4 0.54 Unemployed 2.6 1.2-5.4 0.01 0.9 0-2.8 0.87 Retired 1.1 0.4-2.9 1 Education Primary 0.59 0.2-1.3 0.27 Secondary 1.5 0.7-3.1 0.34 University 0.1 0-0.5 0.02 0.2 0-9 0.05 Illiterate 0.53 0.1-2 0.56 BMI Normal 1.6 0.6-4.1 0.39 Overweight 1.8 0.8-4.2 0.2 Obesity 0.7 0.3-1.4 0.49 Comorbidities Hypertension 0.6 0.3-1.4 0.38 Diabetes 0.4 0.1-1.2 0.2 Low back pain 0.5 0.3-1 0.1 Joint effusion 1.1 0.5-2.9 0.96 Pain, VAS Mild pain 3.1 0.8-11 0.1 Moderate pain 1.6 0.7-3.3 0.25 Severe pain 0.2 0.1-0.6 &lt;0.01 0.4 0.2-0.9 0.03 Disability Moderate handicap 0.5 0.2-1.4 0.32 Severe handicap 1.3 0.7-2.9 0.48 Very severe handicap 0.3 0.1-0.6 &lt;0.01 0.3 0.1-0.7 0.04 Kellgren – Lawrence radiographic grading Grade 2 1.7 0.8-3.5 0.19 Grade 3 0.64 0.3-1.3 0.32 Grade 4 0.6 0.2-1.9 0.35 Conclusion: Neuropathic pain exists during knee OA. We found it in 27.1% of patients followed in a hospital in Cameroon. It is associated with the severity of pain and functional disability. References: [1]French HP, et al. 2017. [2]Bouhassira D, et al. 2005. Disclosure of Interests: None declared