Fifteen Years' Use of Patient-Reported Outcome Measures at the Group and Patient Levels: Trend Analysis

Since 2004, we have collected patient-reported outcome (PRO) data from several Danish patient populations for use at the group and patient levels. The aim of this paper is to highlight trends during the last 15 years with respect to patient inclusion, the methods for collection of PRO data, the processing of the data, and the actual applications and use of the PRO measurements. All PRO data have been collected using the AmbuFlex/WestChronic PRO system, which was developed by the author in 2004 and has been continuously updated since. The analysis of trends was based on a generic model applicable for any kind of clinical health data, according to which any application of clinical data may be divided into four processes: patient identification, data collection, data aggregation, and the actual data use. Data for analysis were generated by a specific application in the system and transferred for analysis to the R package. During the 15-year period, 78,980 patients within 28 different groups of chronic and malignant illnesses have answered 260,433 questionnaires containing a total of 13,538,760 responses. Several marked changes have taken place: (1) the creation of cohorts for clinical epidemiological research purposes has shifted towards cohorts defined by clinical use of PRO data at the patient level; (2) the development of AmbuFlex, where PRO data are used as the entire basis for outpatient follow-up instead of fixed appointments, has undergone exponential growth and the system is currently in use in 47 International Statistical Classification of Diseases and Related Health Problems groups, covering 16,000 patients and 94 departments throughout Denmark; (3) response rates (up to 92%) and low attrition rates have been reached in group level projects, and there are even higher response rates in AmbuFlex where the patients are individually referred; (4) The answering method has shifted, as while in 2005 a total of 66.5% of questionnaires were paper based, this is the case for only 4.3% in 2019; and (5) the approach methods for questionnaires and reminders have changed dramatically from letter, emails, and short message service text messaging to a national, secure electronic mail system through which 93.2% of the communication to patients took place in 2019. The combination of secure email and web-based answering has resulted in a low turnaround time in which half of responses are now received within 5 days. The demand for clinical use of PRO measurements has i