RESUMO
BACKGROUND: Individual illness perception is known to influence a range of outcome variables. However, little is known regarding illness perception in irritable bowel syndrome (IBS) and its relation to the use of the health care system. This study hypothesised a relationship between illness perception and inappropriate health care use (under-, over- and misuse). METHODS: An internet-based, cross-sectional study in participants affected by IBS symptoms was carried out (April - October 2019) using open questions as well as validated standardized instruments, e.g. the illness perception questionnaire revised (IPQ-R) and its subscales. Sub-group comparisons were done non-parametrically and effect sizes were reported. Potential predictors of (1) conventional health care utilisation and (2) utilisation of treatment approaches with lacking or weak evidence regarding effectiveness in IBS were examined with logistic regression analyses and reported as odds ratio (OR) and 95% confidence interval. RESULTS: Data from 513 individuals were available. More than one-third (35.7%) of participants were classified as high utilisers (> 5 doctor visits during the last year). Several indicators of inappropriate health care use were detected, such as a low proportion of state-of-the-art gynaecological evaluation of symptoms (35.0% of women) and a high proportion of individuals taking ineffective and not recommended non-steroidal antirheumatic drugs for IBS (29.4%). A majority (57.7%) used treatment approaches with lacking or weak evidence regarding the effectiveness in IBS (e.g. homeopathy). Being a high utiliser as defined above was predicted by the perceived daily life consequences of IBS (IPQ-R subscale "consequences", OR = 1.189 [1.100-1.284], p ≤ 0.001) and age (OR = 0.980 [0.962-0.998], p = 0.027). The use of treatment approaches with lacking or weak evidence was forecasted by the perceived daily life consequences (OR = 1.155 [1.091-1.223], p ≤ 0.001) and gender (reference category male: OR = 0.537 [0.327-0.881], p = 0.014), however effect sizes were small. CONCLUSIONS: Daily life consequences, perceived cure and personal control as aspects of individual disease perception seem to be related to individuals' health care use. These aspects should be a standard part of the medical interview and actively explored. To face inappropriate health care use patients and professionals need to be trained. Interdisciplinary collaborative care may contribute to enhanced quality of medical supply in IBS.