Abstract
Background
Complete and reliable outcome assessment is important for clinical quality control and research evidence. Online questionnaires offer the opportunity to perform follow-up at distance and desired frequency saving efforts and cost to patients and hospitals increasingly not reimbursed for this service. Patients in this unique study have been invited by mail (not at visit or by phone) and were asked to complete both methods (online, paper) instead of only one option. For the first time, response, completion and reliability of the HOOS, KOOS-PS and New-KSS, popular patient-reported outcomes (PROM's) in TJA were measured.
Methods
Patients (n=107) were invited pre-operative by mail to register at atriumproms.nl (Interactive Studios, Netherlands) and complete PROM's online, followed by a second invitation three days later to complete the same on paper. THA patients (n=48) completed EQ-5D-3L, VAS pain and HOOS. TKA (n=59) questionnaires consisted of KOOS-PS, VAS pain and New-KSS. Reliability was assessed using intraclass correlation coefficient (ICC). ICC was considered excellent >0.75 according to literature.
Results
Overall response rate was 77.6% (83/107) with no difference between THA (77.1%) and TKA (79.3%). Paper had a higher response rate (70.1% vs. 34.9%, p<0.01, Fisher Exact test). However, completion rate was higher online (95%) than on paper (54%, p<0.01). Age had a significant influence on online response rates (<70yrs: 43%, >=70yrs: 23%, p=0.03).
Reliability was excellent in the THA group (ICC: 0.84 – 0.95) except for the EQ-5D-3L (ICC: 0.72). The TKA group showed excellent reliability for VAS-pain (0.92). However, for New-KSS reliability was only good (0.60) or poor for KOOS-PS (0.39).
Conclusions
A high response rate shows patient cooperation making distance follow-up by mail feasible. Online PROM's were only half as popular as paper questionnaires but achieve twice the completion rate. Taking scores online has excellent reliability. Only when conversions are performed (KOOS-PS, EQ-5D) reliability suffers.
