Effect of obesity on self-reported pain and functional disability in patients with knee osteoarthritis in Zaria, North Western Nigeria

Abstract

Introduction: Osteoarthritis (OA) is the most common causes of arthritis in human, with the knee joint being the most commonly affected. Knee OA patients often present with knee pain and varying degree of functional limitation in activities of daily living. The incidence and prevalence of knee OA increases with age and is poised to increase even further in tandem with an expected increase in life expectancy, rise in population age, and increased prevalence of obesity. Obesity is associated with the occurrence and severity of knee OA, and it is perhaps the most amenable of all knee OA risk factors. The contribution of obesity to pain and functional limitation in Nigerian knee OA patients is not well elucidated. This study aims at ascertaining the burden of obesity in Nigerian knee OA patients with regards to its prevalence, effects on pain, and functional disability. Materials and Methods: Between January 2010 and February 2011, 140 consenting knee OA patients were recruited consecutively, as they presented to the Rheumatology Clinic of Ahmadu Bello University Teaching Hospital, Zaria. Knee OA was diagnosed in patients using American College of Rheumatology clinicoradiographic criteria. Information was collected from patient using a pretested interviewer-administered structured question. Pain, stiffness, and functional disability were determined using Likert version of Western Ontario McMaster Universities Osteoarthritis index (WOMAC). Patients were grouped based on body mass index (BMI) into obese (BMI > 30 kg/m2) and nonobese (BMI