The access to and outcomes of elective hip and knee replacement surgery for patients with comorbidities: a study using PROMs and administrative data

Background: Joint replacement surgery is one of the most cost-effective interventions leading to considerable improvements in function and quality of life. The rise in multimorbidity in the UK is leading to an increasing number of patients with long-term conditions (LTCs) undergoing joint replacement surgery. Financially stretched commissioners of health services are seeking to restrict access to routine elective surgery, including hip and knee replacements, despite a lack of evidence to support these decisions. It is therefore important to understand the factors that limit the safety and effectiveness of surgery and how LTCs might have an impact on access to and outcomes of joint replacement. Methods: In this thesis, national patient-level datasets and both quantitative and qualitative research methods were used to investigate the access to and outcomes of hip and knee replacement surgery for patients with 11 different comorbidities. This involved three components: a literature review, methodological work, and empirical work. The literature review explored the outcomes for patients with different comorbidities. The methodological work assessed the agreement between patient-report and administrative data derived comorbidities. Finally, the empirical work explored the severity of joint problems before surgery and the safety and effectiveness outcomes for patients with comorbidities. Semi-structured interviews with healthcare professionals that are involved in the referral and selection of patients for joint replacement surgery were undertaken to provide insight into the factors that influence the access to surgery for patients with comorbidities. Results: The systematic review on outcomes to hip and knee replacement surgery showed that there was limited evidence of the impact of comorbidities on patient-reported outcomes related to effectiveness of joint replacement surgery. Patients with comorbidities reported more severe joint problems before surgery compared to patients without comorbidities, suggesting that patients with comorbidities may be undergoing hip and knee replacement surgery later in the course of their joint disease. This was further supported by the findings from the qualitative study that patients with comorbidities who were considered unsuitable for surgery were ‘lost to the system’ and left to self-manage their comorbidities before being reconsidered for joint replacement surgery. With regards to outcomes, patients with comorbidities have a moderately increased risk of adverse outcomes after hip and knee replacement surgery but benefit almost to the same extent as patients without comorbidities. Patients with comorbidities reported only slightly smaller improvements in severity of joint problems and no difference in quality of life after surgery compared to patients without comorbidities. Patients with multiple comorbidities (two or more comorbidities) reported more severe joint problems before surgery and a slightly higher increased risk of adverse outcomes but nevertheless benefitted considerably from the surgery. Conclusions: This thesis demonstrates that patients with comorbidities may experience inequalities in access to hip and knee replacement surgery even though they benefit almost as much as patients without comorbidities. This finding indicates that the restriction of access to joint replacement surgery based on the presence of comorbidities alone is difficult to justify considering the beneficial impact of the surgery on patients’ lives.