OBJECTIVES - Little is known about the impact of OIC and treatments for OIC on health state utility. Studies often focus on collecting data on changes in OIC status. The objective of this paper is to examine if the utility impact of treatment is driven by change in OIC status, and what the magnitude of the change in utility associated with changes in OIC status is. METHODS - 1352 patients with non-malignant OIC were allocated to one of two, phase III, 12 week randomised controlled trials to study naloxegol. These trials were pooled and prospective analyses on these data were undertaken.  Both trials collected the three level EQ-5D at baseline, week 4 and week 12. EQ-5D scores were converted into estimates of utility using a tariff generated based on UK general population preferences. A repeated measure mixed model (RMMM) regression analysis was conducted to identify the impact of the following factors on utility: age, gender, race, BMI, duration of opioid use, treatment (naloxegol 12.5mg, 25mg or placebo), baseline utility and OIC status (OIC or non-OIC). RESULTS - Baseline utility across all patients was 0.559. The regression demonstrated that baseline utility score (β=-0.532, SE=0.023) and OIC status (β=0.032, SE=0.012) were the only significant predictors of change in utility score (p<0.0001and p=0.008 respectively).  Further univariate analyses examined the effect of OIC status in patient subgroups that had different experiences of laxative treatment. OIC status had an increased and meaningful impact on patients who had previously responded inadequately to laxatives. CONCLUSIONS - OIC status is a significant factor on the impact of treatment on patient’s utility. Furthermore the impact of OIC status is increased in patients who had previously responded inadequately to laxatives.