An analysis of missing items in real-world electronic patient reported outcomes data: implications for clinical care.

The frequency of missingness was highest for functional items, like attending a paid job, suggesting that some respondents (e.g., retirees without a paid job) skipped questions that were less applicable to them. More universal issues for cancer patients, such as emotional well-being, had much lower frequencies of missingness. This suggests differential item completion that warrants further study to understand the inherent drivers. Identifying causes of missingness could improve the clinical utility of ePROs and highlight opportunities to personalize care.