Reliability of patient-reported functional outcome in a joint replacement registry. A comparison of primary responders and non-responders in the Danish Shoulder Arthroplasty Registry.
OBJECTIVE
Patient-reported outcome measures (PROMs) are used by some arthroplasty registries to evaluate results after surgery, but non-response may bias the results. The aim was to identify a potential bias in the outcome scores of subgroups in a cohort of patients from the Danish Shoulder Arthroplasty Registry (DSR) and to characterize non-responders.


METHODS
Patient-reported outcome of 787 patients operated in 2008 was assessed 12 months postoperatively using the Western Ontario Osteoarthritis of the Shoulder (WOOS) index. In January 2012, non-responders and incomplete responders were sent a postal reminder. Non-responders to the postal reminder were contacted by telephone. Total WOOS score and WOOS subscales were compared for initial responders (n = 509), responders to the postal reminder (n = 156), and responders after telephone contact (n = 27). The predefined variables age, sex, diagnosis, geographical region, and reoperation rate were compared for responding and non-responding cohorts.


RESULTS
A postal reminder increased the response rate from 65% (6% incomplete) to 80% (3% incomplete) and telephone contact resulted in a further increase to 82% (2% incomplete). We did not find any statistically significant differences in total WOOS score or in any of the WOOS subscales between responders to the original questionnaire, responders to the postal reminder, and responders after telephone contact. However, a trend of worse outcome for non-responders was found. The response rate was lower in younger patients.


CONCLUSIONS
Non-responders did not appear to bias the overall results after shoulder replacement despite a trend of worse outcome for a subgroup of non-responders. As response rates rose markedly by the use of postal reminders, we recommend the use of reminders in arthroplasty registries using PROMs.
Department of Orthopaedic Surgery, Herlev University Hospital, Denmark. anne.polk@hotmail.com
Anne
A
Polk
Jeppe V
JV
Rasmussen
Stig
S
Brorson
Bo S
BS
Olsen
D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019643:Arthroplasty, Replacement / Q000523:psychology* / Q000706:statistics & numerical data; D015982:Bias; D003718:Denmark; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D012042:Registries; D017010:Reminder Systems; D012189:Retrospective Studies; D057566:Self Report; D012785:Shoulder Joint / Q000601:surgery; D011795:Surveys and Questionnaires; D016896:Treatment Outcome; D055815:Young Adult