Variations in Chronic Pain Intensity and Physical Function by Age and Sex for Patients with Knee Osteoarthritis

Objectives: Treatment-seeking behaviour, evaluation and management approach, as well as responsiveness to management by individuals with knee osteoarthritis (OA) could be hampered by variations of common confounding (constant) factors of knee OA; age and sex. Studies that integrate age and sex variations in clinical factors such as pain intensity and physical function are limited. The aim of this study was to determine age and sex variations in pain intensity and physical function among individuals with knee OA in Nigeria. Design/setting/participants/outcome measures: Eightynine consecutively sampled patients diagnosed with knee OA from three selected public (secondary and tertiary) hospitals in Enugu, South-East Nigeria, participated in this cross-sectional survey. Instruments used were Visual Analogue Scale (VAS) and Ibadan Knee or Hip Osteoarthritis Measure (IKHOAM). Data were analysed using Analysis of Variance (ANOVA) and Students’-test with Bonferroni correction. The level of significance was set at 0.05. Results: Significant variations of age in pain intensity between age groups of 20-39 and each of 40-59 years (MD = -3.68, p = 0.01) and 60-79 years (MD = -3.23, p = 0.04) as well as physical function between age groups of 60-79 and each of 20-39 years (MD = 20.85, p = 0.02) and 40-59 years (MD = 10.70, p = 0.03) were observed. There was a significant sex variation in physical function, (F = 9.57, p < 0.05) but not in pain intensity (F = 2.91, p = 0.09) on oneway ANOVA, with females reporting higher scores on pain intensity (5.29 ± 2.97) and lower scores on physical function (64.06 ± 17.26) than males (3.94 ± 2.29 and 78.77 ± 17.08 respectively). Conclusions: Age and sex should be considered by clinicians in management programs for knee OA to address the specific needs of each individual patient.