Risk factors for pain exacerbation in hip osteoarthritis

Abstract

A primary and debilitating symptom of hip osteoarthritis (OA) is pain around the hip joint. At present, however, the aetiology and risk factors for the intermittent pain or pain exacerbations in people with hip OA are largely unknown. The primary objective of this thesis is to identify the risk factors for pain exacerbations in people with hip OA. In this thesis, an internet-based case-crossover study was designed to assess the relation of potential risk factors to the risk of hip pain exacerbation in people with symptomatic hip OA. Eligible participants with symptomatic hip OA were instructed to complete online questionnaires every ten days over a 90-day follow-up period. In addition, they were required to complete the questionnaire whenever they perceived they were experiencing a hip pain exacerbation. Hip pain exacerbation was defined as an increase of two points in pain intensity compared with baseline on an 11-point numeric rating scale (NRS, 0-10). Among the 252 participants recruited, more than 130 participants had at least one pain exacerbation during the follow-up. Hip injury, episodes of hip “giving way”, poor sleep quality, greater fatigue and daily temperature variation were related to pain exacerbation in people with symptomatic hip OA. Wearing shoes with heel height ≥ 2.5 cm and a longer duration wearing such shoes in the past 24 hours may be protective against hip pain exacerbations. Analgesic medication use during the past seven days was associated with pain exacerbations in people with hip OA but not dietary supplements. The use of multivitamin/mineral supplement, vitamin C, vitamin E, and magnesium was inversely associated with pain exacerbation. Both pain catastrophizing and pain self-efficacy beliefs were associated with pain exacerbations. Whether a causal relationship exists between these risk factors and pain exacerbations should be further validated using additional longitudinal cohort studies to confirm our findings.