The risk of dying following total hip replacement (THR) is low and has declined over the last decades. The influence of comorbidities and worse physical status on mortality leads to the idea that patient-reported health status may also be a predictor of mortality. Although this has not been demonstrated in THR surgery, some studies in other fields have reported an association. The aim of this study was to investigate the relationship between patient-reported health status before THR and the risk of dying up to 5 years post-operatively.

The Swedish Hip Arthroplasty Register runs a nationwide PROMs program including the EQ-5D questionnaire to routinely monitor patients undergoing THR in Sweden. For these analyses, we used register data on 42,862 patients with hip osteoarthritis operated with THR between 2008 and 2012. Relative survival ratio was calculated by dividing the observed survival in the patient group by age- and gender-adjusted expected survival of the general population. Multivariable modelling proceeded with time-transformed Cox proportional hazards. Pre-operative responses to the five EQ-5D dimensions along with age, gender, education status, year of surgery, and hospital type were used as independent variables.

As a group THR patients had a better survival than the general population. Broken down by the five EQ-5D dimensions we observed differentiated survival patters. For all dimensions, those reporting moderate problems (level 2) had higher mortality than those reporting no problems (level 1) and those reporting extreme problems (level 3) had higher mortality than those reporting level 1 or 2.

Worse health status according to the EQ-5D before THR is associated with higher mortality up to five years after surgery. The complexity of the interactions between different patient-factors associated with outcomes complicates accurate assessments of risks and expected benefits for individual patients. EQ-5D responses may be useful in a multifactorial individualized risk assessment before THR.

Prospectively collected data is an important source of information subjected to change over time. What surgeons were doing in 1999 might not be the case anymore in 2016 and this change in time also applies to a number of factors related to the performance and outcome of total hip replacement. We evaluated the evolution of factors related to the patient, the surgical procedure, socio-economy and various outcome parameters after merging the databases of the Swedish Hip Arthroplasty Register, Statistics Sweden and the National Board of Health and Welfare.

Data on 193,253 THRs (164,113 patients) operated between 1999 and 2012 were merged with databases including general information about the Swedish population and about hospital care. We studied the evolution of surgical volume, patient demographics, socio-economic factors, surgical factors, length of stay, mortality rate, adverse events, re-operation and revision rates and PROMs.

Most patients were operated because of primary osteoarthritis and this share increased further during the period at the expense of decreasing number of patients with inflammatory OA and hip fracture. Comorbidity and ASA scores increased for each year. The share of all cemented implants has dropped from 92% to 68% with a corresponding increase of all uncemented from 2% to 16%.

Length of stay decreased with about 50 percent to 4.5 days in 2012. The 30- and 90-day mortality rate dropped to 0.4% and 0.7%. Re-operation and revision rates at 2 years were lower in the more recent years. The postoperative PROMs are improving despite the preoperative pain scores getting worse.

Even in Sweden, always been considered as a very conservative country with regards to hip replacement surgery, the demographics of the patients, the comorbidities and the primary diagnosis for surgery are changing. Despite these changes the outcomes like mortality, re-operations, revisions and PROMs are improving.