Objectives <p>This study aimed to evaluate whether a brief pre-survey reminder prompting patients to reflect on their pre-illness health was associated with altered response patterns in cross-sectional patient-reported outcome measures (PROMs).</p> Methods <p>A cross-sectional study was conducted among 244 inpatients in a hepatobiliary surgery department. Participants were assigned to a control group (standard recall instructions for the EQ-5D-5L and EQ-HWB-9) or a reminder group (identical instructions, preceded by the reminder). Response distributions were compared descriptively, and adjusted ordered logistic regression models were used to assess the association between the reminder and reported problem severity.</p> Results <p>A total of 244 inpatients participated, with 123 in the control group and 121 receiving the pre-illness reminder. There were no missing data for the EQ-5D-5L or EQ-HWB-9 items, and EQ VAS data were missing for three participants only. The reminder group reported lower ceiling effects and higher problem severity across both instruments. In adjusted analyses, the reminder was associated with higher odds of reporting more severe problems across all EQ-5D-5L dimensions, with odds ratios ranging from 1.90 to 3.13, and across seven of the nine EQ-HWB-9 items, with odds ratios ranging from 1.94 to 5.43. The reminder group also reported a lower mean EQ VAS score than the control group: 78.23 versus 82.03, <i>p</i> = 0.002.</p> Conclusions <p>The brief reminder was associated with more severe and differentiated PROM responses. These findings suggest that a pre-illness reference reminder may influence respondents’ appraisal of current health in cross-sectional PROM assessment. However, without an objective benchmark for true health status, the findings should be interpreted as consistent with, but not definitive evidence of, a recalibration-related response process.</p>