FRI0410 PREVALENCE AND FACTORS ASSOCIATED WITH CHRONIC PAIN WITH NEUROPATHIC CHARACTERISTICS IN PATIENTS WITH KNEE OSTEOARTHRITIS IN CAMEROON, SUB-SAHARAN AFRICA

Abstract

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 <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 < 0.01) than patients without neuropathic pain (DN4 < 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<0.05). 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 Table 1Frequency of items in the DN4 questionnaireDN4 itemsFrequency, n (%)Interview of the patientQuestion 1Burning58 (38.4)Painful cold8 (5.3)Electric shocks50 (33.1)Question 2Tingling62 (41)Pins and needles89 (58.9)Numbness68 (45)Itching14 (9.2)Examination of the patientQuestion 3Hypoesthesia to touch16 (10.6)Hypoesthesia to pinprick8 (5.3)Question 4Brushing22 (14.5) Table 2Univariate and multivariate logistic regression analysis of factors associated with neuropathic painVariablesCateLgoryUnadjusted OR95% CIpAdjusted OR95% CIPAge, year<400.20-2.20.3740-651.40.1-2.90.43>650.50.2-1.10.14SexFemale2.20.7-6.20.18Male1OccupationStudent1.30.1-15.31Employed3.11.3-6.90.0081.40.3-4.40.54Unemployed2.61.2-5.40.010.90-2.80.87Retired1.10.4-2.91EducationPrimary0.590.2-1.30.27Secondary1.50.7-3.10.34University0.10-0.50.020.20-90.05Illiterate0.530.1-20.56BMINormal1.60.6-4.10.39Overweight1.80.8-4.20.2Obesity0.70.3-1.40.49ComorbiditiesHypertension0.60.3-1.40.38Diabetes0.40.1-1.20.2Low back pain0.50.3-10.1Joint effusion1.10.5-2.90.96Pain, VASMild pain3.10.8-110.1Moderate pain1.60.7-3.30.25Severe pain0.20.1-0.6<0.010.40.2-0.90.03DisabilityModerate handicap0.50.2-1.40.32Severe handicap1.30.7-2.90.48Very severe handicap0.30.1-0.6<0.010.30.1-0.70.04Kellgren – Lawrence radiographic gradingGrade 21.70.8-3.50.19Grade 30.640.3-1.30.32Grade 40.60.2-1.90.35