Patient factors and health outcomes associated with illness perceptions in people with gout

Abstract

Objective: Illness perceptions are views and beliefs formed in response to a health threat, and they may influence self-management behaviours and chronic disease outcomes. Despite effective medication, sub-optimal outcomes in gout are common. This study aimed to quantitatively investigate illness perceptions in gout to examine how illness perceptions relate to health outcomes.

Methods: Data were obtained from a randomized controlled trial in which people with gout (n = 493) completed surveys measuring illness perceptions [Brief Illness Perception Questionnaire (B-IPQ)], gout flares, medication adherence, health-related quality of life, health-care utilization, and productivity, alongside serum urate blood tests at baseline, and at 6- and 12-month follow-ups. Multivariable linear regression identified patient factors independently associated with each B-IPQ item score. Logistic and linear regression, adjusted for age and sex, determined whether baseline B-IPQ items could predict current and future health outcomes.

Results: Younger individuals and those with severe gout were more likely to experience pessimistic illness perceptions at baseline. Optimistic illness perceptions were associated with lower odds of having had at least one flare in the preceding 6 months. Every 1-point increase in B-IPQ treatment control, indicating an increasingly optimistic view that gout is treatable, decreased the odds of a recent flare prior to baseline by 33% [odds ratio (OR): 0.67; 95% CI: 0.53, 0.85; P < 0.001] and prior to the 12-month follow-up by 15% (OR: 0.85; 95% CI: 0.76,0.96; P = 0.01). Pessimistic illness perceptions also predicted poorer medication adherence, health-related quality of life, and productivity, but not serum urate levels.

Conclusion: Modifying pessimistic illness perceptions, including, but not limited to, patient education, may promote prudent self-management behaviours and better outcomes in gout.

Trial registration: Australian New Zealand Clinical Trials Registry; https://www.anzctr.org.au/, ACTRN12616000455460.

Keywords: B-IPQ; gout; illness perceptions; medication adherence; patient-reported outcomes; serum urate.