National PROMs data and the National Joint Registry. A report on the data quality and completeness

Aims:

Since April 2009, patients receiving NHS funded primary elective hip or knee replacements (THR or TKR) should be invited to complete Patient Reported Outcome Measures (PROMs). The aim of this descriptive study was to use National Joint Registry (NJR) data to identify patient and demographic differences between those with complete versus those with missing PROMs.

Methods:

Patients undergoing publicly funded elective primary THR or TKR between April 2009 and December 2018 recorded in the NJR were eligible. NJR data was linked to the English Hospital Episode Statistics (HES), and PROMs data. Oxford Hip/Knee scores (OHS/OKS) were eligible for inclusion if recorded up to 18 weeks preoperatively (Q1) and 6-12 months postoperatively (Q2). Proportions were used to describe the completeness of PROMs data. The following variables were assessed to determine associations with PROM data completeness: age, gender, ASA grade, body mass index, socioeconomic deprivation, baseline (Q1) OHS/OKS, hospital trust. 

Results:

Of 570,449 eligible TKRs and 507,962 eligible THRs, complete preoperative and postoperative PROMs were available for 229,794 TKRs (40.3%) and 210,929 THRs (41.5%). No differences were observed in patient and demographic factors between those with and without complete PROMs. Patients with complete PROMs had a higher preoperative PROMs score (less pain and functional limitations) than those with preoperative but no postoperative PROMs (TKR: median OKS=19 versus 15; THR: median OHS=17 versus 14). For Q2 PROMs the median trust-level completeness was 71% OKS (60%-76%) and 72% OHS (62%-77%), with little variation between high and low volume trusts. In contrast, Q1 completeness varied between trusts (69% high volume centres vs. 57% low). 

Conclusion:

Up to 60% of patients did not have complete preoperative and postoperative PROMs. However, these patients were similar to those with complete PROMs in terms of patient and demographic factors as well as revision and mortality outcomes. PROMs that are collected are likely generalisable to the wider eligible THR and TKR population.