Periprosthetic Joint Infection After Total Knee Arthroplasty With or Without Antibiotic Bone Cement.

Importance: Despite increased use of antibiotic-loaded bone cement (ALBC) in joint arthroplasty over recent decades, current evidence for prophylactic use of ALBC to reduce risk of periprosthetic joint infection (PJI) is insufficient. Objective: To compare the rate of revision attributed to PJI following primary total knee arthroplasty (TKA) using ALBC vs plain bone cement. Design, Setting, and Participants: This international cohort study used data from 14 national or regional joint arthroplasty registries in Australia, Denmark, Finland, Germany, Italy, New Zealand, Norway, Romania, Sweden, Switzerland, the Netherlands, the UK, and the US. The study included primary TKAs for osteoarthritis registered from January 1, 2010, to December 31, 2020, and followed-up until December 31, 2021. Data analysis was performed from April to September 2023. Exposure: Primary TKA with ALBC vs plain bone cement. Main Outcomes and Measures: The primary outcome was risk of 1-year revision for PJI. Using a distributed data network analysis method, data were harmonized, and a cumulative revision rate was calculated (1 - Kaplan-Meier), and Cox regression analyses were performed within the 10 registries using both cement types. A meta-analysis was then performed to combine all aggregated data and evaluate the risk of 1-year revision for PJI and all causes. Results: Among 2 168 924 TKAs included, 93% were performed with ALBC. Most TKAs were performed in female patients (59.5%) and patients aged 65 to 74 years (39.9%), fully cemented (92.2%), and in the 2015 to 2020 period (62.5%). All participating registries reported a cumulative 1-year revision rate for PJI of less than 1% following primary TKA with ALBC (range, 0.21%-0.80%) and with plain bone cement (range, 0.23%-0.70%). The meta-analyses based on adjusted Cox regression for 1 917 190 TKAs showed no statistically significant difference at 1 year in risk of revision for PJI (hazard rate ratio, 1.16; 95% CI, 0.89-1.52) or for all causes (hazard rate ratio, 1.12; 95% CI, 0.89-1.40) among TKAs performed with ALBC vs plain bone cement. Conclusions and Relevance: In this study, the risk of revision for PJI was similar between ALBC and plain bone cement following primary TKA. Any additional costs of ALBC and its relative value in reducing revision risk should be considered in the context of the overall health care delivery system.

Enhancing the data capture of periprosthetic joint infections in the Danish Knee Arthroplasty Registry: validity assessment and incidence estimation.

BACKGROUND AND PURPOSE: Revisions due to periprosthetic joint infection (PJI) are underestimated in national arthroplasty registries. Our primary objective was to assess the validity in the Danish Knee Arthroplasty Register (DKR) of revisions performed due to PJI against the Healthcare-Associated Infections Database (HAIBA). The secondary aim was to describe the cumulative incidences of revision due to PJI within 1 year of primary total knee arthroplasty (TKA) according to the DKR, HAIBA, and DKR/HAIBA combined. METHODS: This longitudinal observational cohort study included 56,305 primary TKAs (2010-2018), reported in both the DKR and HAIBA. In the DKR, revision performed due to PJI was based on pre- and intraoperative assessment disclosed by the surgeon immediately after surgery. In HAIBA, PJI was identified from knee-related revision procedures coinciding with 2 biopsies with identical microbiological pathogens. We calculated the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of revision due to PJI in the DKR (vs. HAIBA, within 1 year of TKA) with 95% confidence intervals (CI). Cumulative incidences were calculated using the Kaplan-Meier method. RESULTS: The DKR's sensitivity for PJI revision was 58% (CI 53-62) and varied by TKA year (41%-68%) and prosthetic type (31% for monoblock; 63% for modular). The specificity was 99.8% (CI 99.7-99.8), PPV 64% (CI 62-72), and NPV 99.6% (CI 99.6-99.7). 80% of PJI cases not captured by the DKR were caused by non-reporting rather than misclassification. 33% of PJI cases in the DKR or HAIBA were culture-negative. Considering potential misclassifications, the best-case sensitivity was 64%. The cumulative incidences of PJI were 0.8% in the DKR, 0.9% in HAIBA, and 1.1% when combining data. CONCLUSION: The sensitivity of revision due to PJI in the DKR was 58%. The cumulative incidence of PJI within 1 year after TKA was highest (1.1%) when combining the DKR and HAIBA, showing that incorporating microbiology data into arthroplasty registries can enhance PJI validity.

Mortality in patients with incident rheumatoid arthritis and depression: a Danish cohort study of 11 071 patients and 55 355 comparators.

OBJECTIVES: In patients with RA, the association between mortality and depression has been investigated only in patients with prevalent RA. In this study, we estimated the mortality risk associated with depression, defined as the first filling of a prescription for antidepressants, in patients with incident RA and background population comparators. METHODS: From 2008 to 2018, we identified patients with incident RA in the nationwide Danish rheumatologic database, DANBIO. For each patient, we randomly selected five comparators. Participants were not treated with antidepressants or diagnosed with depression 3 years prior to the index date. From other registers we collected data on socioeconomic status, mortality and cause of death using unique personal identifiers. Using Cox models, we calculated hazard rate ratios (HRR) with 95% CI. RESULTS: In depressed patients with RA vs patients without depression, adjusted HRR for all-cause mortality was 5.34 (95% CI 3.02, 9.45) during 0-2 years and 3.15 (95% CI 2.62, 3.79) during the total follow-up period, and highest in patients <55 years with HRR 8.13 (95% CI 3.89, 17.02). In comparators with depression vs comparators without depression, the association with mortality was similar to that in patients with RA. There were no unnatural causes of death among depressed patients with RA. The most frequent natural causes of death were cancer, cardiovascular disease, stroke and pneumonia. CONCLUSION: In patients with RA, depression was a predictor of death but with a strength similar to that in matched comparators.

Any infection among patients with hip fracture: Predictive ability of Charlson, Elixhauser, Rx-Risk, and Nordic comorbidity indices.

BACKGROUND: In studies on infection after hip fracture surgery, a common and serious complication, it remains unknown which comorbidity index is best for case-mix confounder adjustment. We evaluated the predictive ability of Charlson Comorbidity Index (CCI), Elixhauser Comorbidity Index (ECI), Rx-Risk Index (Rx-Risk), and Nordic Multimorbidity Index (NMI) for any infection up to 1 year from discharge after hip fracture surgery. METHODS: Using Danish medical registries, we included 92,600 patients (mean age 83 years) surgically treated for hip fracture between 2004 and 2018. Comorbidity-index scores were calculated using prevalence of diagnosis codes, prescription codes, or both. Lookback periods of 1, 5, and 10 years were applied. Logistic regression was used to calculate c-index to assess discrimination of comorbidity indices individually and in combination with a base model of age and sex. Outcome was any infection (not only surgical site infection) in-hospital and 1 year after discharge. RESULTS: At 10-year lookback period, the c-index for individual comorbidity indices for in-hospital infections varied from 0.53 to 0.56, similar to base model alone (0.56). The predictive ability of comorbidity indices in combination with base model varied from 0.56 to 0.57. Within 1 year after discharge, NMI in combination with base model had best predictive ability for infection (c-index = 0.62), followed by CCI and ECI (c-index = 0.60) and Rx-Risk (c-index = 0.58). Discrimination was similar for all lookback periods. CONCLUSIONS: Comorbidity indices have low predictive ability for any infection up to 1 year after hip fracture surgery, similar to that of age and sex alone. For case-mix adjustment, evaluated comorbidity indices are of equal value.

Temporal trends in revision rate due to knee periprosthetic joint infection: a study of 115,120 cases from the Danish Knee Arthroplasty Register.

BACKGROUND AND PURPOSE: We aimed to examine the temporal trends in periprosthetic joint infection (PJI) revision incidence after knee arthroplasty (KA) from 1997 through 2019. PATIENTS AND METHODS: 115,120 primary KA cases from the Danish Knee Arthroplasty Register were followed until the first PJI revision. We computed cumulative incidences and adjusted hazard ratios (aHRs) of PJI revision by calendar periods and several patient- and surgical-related risk factors. Results were analyzed from 0-3 months and from 3-12 months after KA. RESULTS: The overall 1-year PJI revision incidence was 0.7%, increasing from 0.5% to 0.7% (1997 through 2019). The incidence of PJI revision within 3 months increased from 0.1% to 0.5% (1997 through 2019). The adjusted hazard ratio (aHR) within 1 year of primary KA was 5.1 comparing 2017-2019 with 2001-2004. The PJI revision incidence from 3-12 months of KA decreased from 0.4% to 0.2%, with an aHR of 0.5 for 2017-2019 vs. 2001-2004. Male sex, age 75-84 (vs. 65-74), and extreme obesity (vs. normal weight) were positively associated with the risk of PJI revision within 3 months, whereas only male sex was associated from 3-12 months. Partial knee arthroplasty (PKA) vs. total KA was associated with a lower risk of PJI revision both within 3 months and 3-12 months of KA. CONCLUSION: We observed an increase in PJI revision within 3 months of KA, and a decrease in PJI revision incidence from 3-12 months from 1997 through 2019. The reasons for this observed time-trend are thought to be multifactorial. PKA was associated with a lower risk of PJI revision.

Current Trends in Comorbidity Prevalence and Associated Mortality in a Population-Based Cohort of Hip Fracture Patients in Denmark.

Background and Purpose: Patients with hip fractures often have comorbidities, but detailed data on comorbidity and its impact on prognosis are lacking. We described the current trends in the prevalence of comorbidity and the magnitude of the associated mortality. Patients and Methods: From the Danish Multidisciplinary Hip Fracture Registry we included 31,443 hip fracture patients (diagnosed in 2014-2018). We calculated the prevalence of individual diseases and comorbidity measured with the Charlson Comorbidity Index (CCI), the Elixhauser Index, and the Rx-Risk Index. We calculated sex and age-adjusted odds ratios (aORs) for 30-day mortality and hazard ratios (aHRS) for one-year mortality with 95% confidence intervals (CI). Results: The most common diseases identified with the CCI were cerebrovascular diseases (18%), malignancies (17%), chronic pulmonary disease (14%), and dementia (11%). Using the Elixhauser Index, hypertension (37%), cardiac arrhythmias (21%), and fluid and electrolyte disorders (15%) were most prevalent, while ischemic heart disease (42%), hypertension (39%), and use of antiplatelets (37%) were most prevalent when using the Rx-Risk Index. Using the Rx-Risk Index, only 28% of patients had no comorbidity compared to 38% for CCI and 44% for the Elixhauser Index, and the prevalence was stable through the years. Compared to patients with no comorbidity, patients with very severe comorbidity had an aORs for 30-day mortality of 2.6 (CI: 2.4-2.9) using CCI, 2.6 (CI: 2.4-3.1) using the Elixhauser Index, and 3.1 (CI: 2.7-3.4) using the Rx-Risk Index. Interpretation: More than 50% of the patients with hip fractures have moderate to very severe comorbidity, with considerable variation between indices. The prevalence of individual diseases varies considerably. All indices had comparable dose-response associations with mortality. These results are relevant for clinicians to amend prevention and target care, and for researchers to decide which comorbidity measure to use depending on the research question.

Increasing risk of revision due to infection after primary total hip arthroplasty: results from the Nordic Arthroplasty Register Association.

BACKGROUND AND PURPOSE: The incidence of periprosthetic joint infection after total hip arthroplasty (THA) may be increasing. We performed time-trend analyses of risk, rates, and timing of revision due to infection after primary THAs in the Nordic countries from the period 2004-2018. PATIENTS AND METHODS: 569,463 primary THAs reported to the Nordic Arthroplasty Register Association from 2004 to 2018 were studied. Absolute risk estimates were calculated by Kaplan-Meier and cumulative incidence function methods, whereas adjusted hazard ratios (aHR) were assessed by Cox regression with the first revision due to infection after primary THA as primary endpoint. In addition, we explored changes in the time span from primary THA to revision due to infection. RESULTS: 5,653 (1.0%) primary THAs were revised due to infection during a median follow-up time of 5.4 (IQR 2.5-8.9) years after surgery. Compared with the period 2004-2008, the aHRs for revision were 1.4 (95% confidence interval [CI] 1.3-1.5) for 2009-2013, and 1.9 (CI 1.7-2.0) for 2014-2018. The absolute 5-year rates of revision due to infection were 0.7% (CI 0.7-0.7), 1.0% (CI 0.9-1.0), and 1.2% (CI 1.2-1.3) for the 3 time periods respectively. We found changes in the time span from primary THA to revision due to infection. Compared with 2004-2008, the aHR for revision within 30 days after THA was 2.5 (CI 2.1-2.9) for 2009-2013, and 3.4 (CI 3.0-3.9) for 2013-2018. The aHR for revision within 31-90 days after THA was 1.5 (CI 1.3-1.9) for 2009-2013, and 2.5 (CI 2.1-3.0) for 2013-2018, compared with 2004-2008. CONCLUSION: The risk of revision due to infection after primary THA almost doubled, both in absolute cumulative incidence and in relative risk, throughout the period 2004-2018. This increase was mainly due to an increased risk of revision within 90 days of THA. This may reflect a "true" increase (i.e., frailer patients or more use of uncemented implants) and/or an "apparent" increase (i.e., improved diagnostics, changed revision strategy, or completeness of reporting) in incidence of periprosthetic joint infection. It is not possible to disclose such changes in the present study, and this warrants further research.

Long-Term Temporal Trends in Survival Among Danish Patients with Advanced Cutaneous Melanoma: A Nationwide Follow-Up Study.

Introduction: Population-based data on survival trends over time among patients with advanced cutaneous melanoma are lacking. We examined changes in mortality for patients diagnosed from 1980 to 2011 in a nationwide historical follow-up study using population-based medical registries from Denmark. Material and Methods: The study population included all Danish patients with an incident diagnosis of advanced (metastatic or unresectable stage IIIA, IIIB, IIIC, or IV) cutaneous melanoma (ie, initial diagnosis for melanoma at stage III/IV) between 1980-2011 and who were followed-up until 2013. For each patient, we randomly matched 100 individuals from the general population on sex and year of birth. Age-standardized mortality rates were calculated by calendar year of diagnosis overall, 30 days after diagnosis, and during 31 to 364 days and 0-10 years after diagnosis. Stratified Cox's proportional hazards regression was used to compute hazard ratios. Results: We identified a total of 1236 patients and 123,600 comparison cohort members. We observed that the standardized mortality rates of patients with advanced melanoma dropped from the 1980s onwards, but remain high (eg, 74.3 and 248.4 per 1000 person-years in 0-30 days and 31-364 days after diagnosis, respectively, for patients diagnosed during 2008-2011). Compared with the general population, patients with advanced melanoma had a 10.4-fold increased hazard of death during 0-10 years of follow-up. The highest relative mortality was found for the first year following melanoma diagnosis. No improvements in survival compared to the general population were observed in the most recent years of the study period, thus in 2004-2007 and 2008-2011. Discussion and Conclusion: Survival of patients with advanced cutaneous melanoma in Denmark improved between 1980 and 2013 but appears to have leveled off in the years leading up to more widespread introduction of newer immuno-oncology therapies.

Does choice of bearings influence the survival of cementless total hip arthroplasty in patients aged 20-55 years? Comparison of 21,594 patients reported to the Nordic Arthroplasty Register Association dataset 2005-2017.

BACKGROUND AND PURPOSE: The bearings with the best survivorship for young patients with total hip arthroplasty (THA) should be identified. We compared hazard ratios (HR) of revision of primary stemmed cementless THAs with metal-on-metal (MoM), ceramic-on-ceramic (CoC), and ceramic-on-highly-crosslinked-polyethylene (CoXLP) with that of metal-on-highly-crosslinked-polyethylene (MoXLP) bearings in patients aged 20-55 years with primary osteoarthritis or childhood hip disorders. PATIENTS AND METHODS: From the Nordic Arthroplasty Register Association dataset we included 1,813 MoM, 3,615 CoC, 5,947 CoXLP, and 10,219 MoXLP THA in patients operated on between 2005 and 2017 in a prospective cohort study. We used the Kaplan-Meier estimator for THA survivorship and Cox regression to estimate HR of revision adjusted for confounders (including 95% confidence intervals [CI]). MoXLP was used as reference. HRs were calculated during 3 intervals (0-2, 2-7, and 7-13 years) to meet the assumption of proportional hazards. RESULTS: Median follow-up was 5 years for MoXLP, 10 years for MoM, 6 years for CoC, and 4 years for CoXLP. 13-year Kaplan-Meier survival estimates were 95% (CI 94-95) for MoXLP, 82% (CI 80-84) for MoM, 93% (CI 92-95) for CoC, and 93% (CI 92-94) for CoXLP bearings. MoM had higher 2-7 and 7-13 years' adjusted HRs of revision (3.6, CI 2.3-5.7 and 4.1, CI 1.7-10). MoXLP, CoC, and CoXLP had similar HRs in all 3 periods. The 7-13-year adjusted HRs of revision of CoC and CoXLP were statistically non-significantly higher. CONCLUSION: In young patients, MoXLP for primary cementless THA had higher revision-free survival and lower HR for revision than MoM bearings. Longer follow-up is needed to compare MoXLP, CoC, and CoXLP.

Genome-wide association study of osteonecrosis of the jaw in Danish patients receiving antiresorptive therapy for osteoporosis: A case-control study.

Background: Prior studies of the pharmacogenomics of osteonecrosis of the jaw (ONJ) have had various methodological limitations, including using candidate gene selection as their sole strategy, a small number of ONJ cases, or a study population based on an oncology setting. Objectives: The aim of our case-control study was to evaluate previously reported associations between genetic factors and ONJ, which were based on either genome-wide association studies (GWAS) or candidate gene approaches. Furthermore, we aimed to identify genetic risk factors for ONJ by using GWAS to determine single-nucleotide polymorphisms (SNPs) with statistically significant differences in frequency between ONJ patients and osteoporosis controls. Methods: Patients with medically confirmed ONJ and who were registered in the Scandinavian Cohort of ONJ patients were included. Controls from the general population were matched on age (±5 years), sex, and cumulative antiresorptive drug exposure. The ONJ diagnosis date for cases corresponded to the index date for matched controls. DNA isolation, genotyping, and data analyses were performed by Q2/EA Genomics using standard protocols and best practices. Blood or tissue samples for 55 ONJ cases and 125 controls were collected. Due to the low quality of the tissue samples, final analyses were based on blood samples of 40 ONJ cases and 124 controls. Results: We detected no significant genome-wide associations. Of the 43 SNPs with ONJ association in prior studies, none were replicated in our study. Conclusions: Even though our study sample is the largest to date, we had limited statistical power for GWAS but adequate power for replication analyses. Our study provides no evidence for any genetic predisposition to ONJ. Future studies could increase their statistical power by combining ONJ GWAS datasets and by performing a meta-analysis or pursuing a sequencing strategy in order to identify rare variants.

Association between duration of anticoagulant thromboprophylaxis and revision rate in primary total hip arthroplasty: a Danish and Norwegian nationwide cohort study.

BACKGROUND AND PURPOSE: There are concerns that bleeding following primary total hip arthroplasty (THA) contributes to prolonged wound drainage and prosthetic joint infection (PJI). We examined whether short (1-5 days), medium (6-14 days), and extended (≥ 15 days) duration of thromboprophylaxis is associated with the 5-year revision rate after THA due to osteoarthritis. PATIENTS AND METHODS: We performed a cohort study based on data from hip arthroplasty and administrative registries in Denmark and Norway (2008-2014). The outcome was revision surgery due to PJI, aseptic loosening or any cause, and patient mortality. Adjusted cause-specific hazard ratios (HRs) were analyzed with Cox regression analyses. RESULTS: Among 50,482 THA patients, 8,333 received short, 17,009 received medium, and 25,140 received extended thromboprophylaxis. The HRs for revision due to PJI within 5 years were 1.0 (95%CI 0.7-1.3) and 1.1 (CI 0.9-1.3) for short and extended vs. medium treatment, whereas HR for extended vs. medium prophylaxis was 1.5 (CI 1.2-2.0) within 3 months. The HRs for revision due to aseptic loosening within 5 years were 1.0 (CI 0.7-1.4) and 1.1 (CI 0.9-1.4) for short and extended vs. medium treatment. The HRs for any revision within 5 years were 0.9 (CI 0.8-1.1) and 0.9 (CI 0.8-1.0) for short and extended vs. medium treatment. Extended vs. medium prophylaxis was associated with a decreased 0-3 month mortality. The absolute differences at 5 years were ≤ 1%. CONCLUSION: Our data suggests no association between duration of anticoagulant thromboprophylaxis and revision rate within 5 years of primary THA. The extended thromboprophylaxis might be associated with early increased revision rate due to PJI but also with lower mortality; however, the clinical relevance of this finding requires further research.

The association between socioeconomic status and the 90-day risk of cardiovascular events after total hip arthroplasty - registry-based study of 103,286 patients.

BACKGROUND AND PURPOSE: Patients receiving a total hip arthroplasty (THA) are subsequently at an increased risk of cardiovascular disease (CVD). Further, socioeconomic status (SES) has an effect on CVD. We evaluated whether low SES is associated with a higher risk of readmission due to CVD after THA within 90 days in a setting with universal tax-supported healthcare. PATIENTS AND METHODS: We performed a nationwide population-based cohort study using Danish health registries from 1995 to 2017. Individual-based information on SES markers (cohabitation, education, income, and liquid assets) was obtained for all participants. The outcome was any hospital-treated CVD. The data was transformed using the pseudo-observation method to enable an estimation of the adjusted risk ratios (RRs) with 95% confidence intervals (CI) for each marker using generalized linear regression. RESULTS: Among 103,286 THA patients, 452 were hospitalized with CVD within 90 days after surgery. Low SES seemed to be associated with a small increased risk of CVD, as the RRs for any CVD were 1.1 (95% CI 0.7-1.7) for patients living alone vs. cohabiting, 1.3 (CI 0.7- .3) for low education vs. high, 1.4 (CI 0.8-2.6) for low income vs. high, and 1.3 (CI 0.8-2.1) for low liquid assets vs. high. CONCLUSION: Living alone, low education, low income, and low liquid assets seem to be associated with a small increased risk of readmission due to CVD 90 days after THA. Wide confidence intervals in risk should be considered when interpreting the study results.

Risk of reoperation due to surgical site infection in 74,771 hip fracture patients: a Danish nationwide cohort study.

BACKGROUND AND PURPOSE: Surgical site infection (SSI) after hip fracture surgery is a feared condition. We examined the trend in incidence of reoperation due to SSI up to 1 year following hip fracture surgery from 2005 to 2016 and risk factors of SSI by age, sex, comorbidity, type of fracture, and surgery. PATIENTS AND METHODS: We conducted a population-based, nationwide cohort study using data from the Danish Multidisciplinary Hip Fracture Register (DMHFR). We included 74,771 patients aged 65 and up who underwent surgery from 2005 to 2016 for all types of hip fracture. We calculated net risk of reoperation using Kaplan­Meier method, and, with Cox regression, adjusted hazard ratios (HRs) with a 95% confidence interval (CI) for reoperation due to SSI. RESULTS: Overall, the 1-year net risk of reoperation due to SSI was 1.6%. The HR was higher for patients undergoing total/hemiarthroplasty surgery versus internal fixation (HR = 1.5; 95%CI 1.3­1.8) and lower for patients with per-/subtrochanteric fracture versus femoral neck fracture (HR = 0.6; CI 0.6­0.7). The risk of reoperation due to SSI decreased over time; HR was 0.7 (CI 0.5­0.8) for 2015­2016 compared with 2005­2006. Risk of reoperation decreased with increasing age; the HR was 0.8 (CI 0.7­1.0) in the more than 85-year-olds compared with 65­74-year-old patients. Charlson Comorbidity Index of ≥ 3 was associated with a higher risk of reoperation due to SSI, HR was 1.3 (CI 1.1­1.6). INTERPRETATION: The net risk of reoperations due to SSI in our study was lower than previously assumed. We identified several risk factors for increased risk of reoperation due to SSI, most noticeably treatment with arthroplasty vs. internal fixation, as well as younger age, high comorbidity burden, and femoral neck fracture diagnosis.

The Interaction Effect Between Previous Stroke and Hip Fracture on Postoperative Mortality: A Nationwide Cohort Study.

Purpose: It remains uncertain how a history of stroke impacts the prognosis for patients with hip fracture. This study aimed to evaluate mortality following hip fracture surgery by comparing patients with and without a history of stroke. Patients and Methods: All patients aged 65 years or above in Denmark receiving hip fracture surgery between 2010 and 2018. For every patient, 10 individuals from the general population without hip fracture were sampled. Comparators had a similar stroke history, age, and sex on the date of hip fracture surgery (index date). We established four cohorts: hip fracture patients with/without stroke and non-hip fracture patients with/without stroke. Outcomes were all-cause mortality at 0-30 days, 31-365 days and 1 to 5 years. Direct standardized mortality rates (MR) with 95% confidence intervals (CI) were computed. We calculated the interaction contrast to estimate excess absolute mortality among patients with both hip fracture and stroke. Through a Cox proportional hazards model, we estimated the hazard ratio (HR) and the attributable proportion as a measure of excess relative mortality attributable to interaction. Results: Of the hip fracture patients, 8433 had a stroke history and 44,997 did not. Of the non-hip fracture patients, 84,330 had a stroke history and 449,962 did not. Corresponding 30-day MRs/100 person years were 148.4 (95% CI: 138.8-158.7), 124.3 (95% CI: 120.7-128.1), 14.3 (95% CI: 13.4-15.2) and 8.4 (95% CI: 8.1-8.7). The interaction contrast was 18.2 (95% CI: 7.5-28.8), and the attributable proportion was 9.0% (95% CI: 2.9-15.1). No interaction was present beyond 30 days. Conclusion: We observed excess short-term mortality in patients with stroke and hip fracture, but the effect disappeared at later follow-up periods. Clinicians are encouraged to pay rigorous attention to early complications among hip fracture patients with stroke, as this may serve as a way to reduce mortality.

Do changes in outcomes following primary and revision hip replacement differ and relate to markers of socioeconomic status? A 1-year population-based cohort study.

BACKGROUND AND PURPOSE: There is little evidence on improvement after revision total hip replacement (THR). Moreover, improvements may be associated with socioeconomic status (SES). We investigated whether changes in Harris Hip Score (HHS) differ among patients undergoing primary and revision THR, and their association with markers of SES. PATIENTS AND METHODS: We conducted a populationbased cohort study on 16,932 patients undergoing primary and/or revision THR from 1995 to 2018 due to hip osteoarthritis. The patients were identified in the Danish Hip Arthroplasty Registry. Outcome was defined as mean change in HHS (0-100) from baseline to 1-year follow-up, and its association with SES markers (education, cohabiting, and wealth) was analyzed using multiple linear regression adjusting for sex, age, comorbidities, and baseline HHS. RESULTS: At 1-year follow-up, HHS improved clinically relevant for patients undergoing both primary THR: mean 43 (95% CI 43-43) and revision THR: mean 31 (CI 29-33); however, the increase was 12 points (CI 10-14) higher for primary THR. For primary THR, improvements were 0.9 points (CI 0.4-1.5) higher for patients with high educational level compared with low educational level, 0.4 points (CI 0.0-0.8) higher for patients cohabiting compared with living alone, and 2.6 points higher (CI 2.1-3.0) for patients with high wealth compared with low wealth. INTERPRETATION: Patients undergoing primary THR achieve higher improvements on HHS than patients undergoing revision THR, and the improvements are negatively related to markers of low SES. Health professionals should be aware of these characteristics and be able to identify patients who may benefit from extra rehabilitation to improve outcomes after THR to ensure equality in health.

Comorbidity and Quality of In-Hospital Care for Hip Fracture Patients.

OBJECTIVES: We examined whether the comorbidity burden of patients with hip fracture was associated with quality of in-hospital care reflected by fulfillment of process performance measures. DESIGN: Population-based cohort study using prospectively collected data from the Danish Multidisciplinary Hip Fracture Registry (DMHFR). SETTING AND PARTICIPANTS: Patients aged 65 years or older with an incident hip fracture from 2014 to 2018 registered in the DMHFR (n = 31,443). METHODS: Comorbidity was measured using the Charlson Comorbidity Index based on hospital diagnoses. Quality of in-hospital care was defined as fulfillment of eligible process performance measures, including preoperative optimization, early surgery, early mobilization, pain assessment, basic mobility, nutritional risk, need for anti-osteoporotic medication, fall prevention, and a post-discharge rehabilitation program, reflecting guideline-recommended in-hospital care. The outcomes were (1) an all-or-none composite measure defined as fulfillment of all relevant process performance measures, and (2) fulfillment of the individual process performance measures. Using binary regression, we calculated relative risk (RR) for the association between comorbidity level and outcomes. RESULTS: The overall proportion of patients with hip fracture who fulfilled the all-or-none measure was 31%. Among patients with no comorbidity, 34% fulfilled the all-or-none measure versus 29% among patients with high comorbidity (Charlson ≥ 3). This corresponds to a 15% lower chance (RR = 0.85, 95% confidence interval 0.81-0.89). Increasing comorbidity was also associated with lower fulfillment of the individual process performance measures. The largest difference was seen for preoperative optimization, early surgery, and early mobilization, where patients with high comorbidity had 6% to 11% lower chance of fulfillment of these process performance measures compared with patients without comorbidity. CONCLUSION AND IMPLICATIONS: Increasing level of comorbidity was associated with lower quality of in-hospital care among patients with hip fracture. Our results highlight the need for tailored clinical initiatives to ensure that comorbid patients also benefit from the positive progress in hip fracture care in recent years.

Postoperative complications, mortality, and quality of in-hospital care among hip fracture patients with Parkinson's disease.

AIM: The aim of this study was to investigate the association between Parkinson's disease (PD) and postoperative complications, mortality, and quality of in-hospital care in patients with hip fracture. METHODS: We included patients aged 65+ years with an incident hip fracture from 2004-2017, registered in the Danish Multidisciplinary Hip Fracture Registry. Patients with PD were identified using diagnosis codes prior to hip fracture. Using log-binomial regression, we calculated both 30-day crude and adjusted risk ratios (aRR) with 95% confidence intervals (CIs) for the following outcomes: any hospital-treated infections, pneumonia, urinary tract infection, sepsis, community-treated infections, cardiovascular events, mortality, and fulfilment of quality indicators of in-hospital care. Analyses were adjusted for age, sex and Charlson comorbidity index score. RESULTS: We identified 77,550 hip fracture patients of which 1,915 had PD. Compared to non-PD, patients with PD had higher risk of any hospital-treated - (aRR = 1.27 (CI: 1.10-1.45) and community-treated infection (aRR = 1.22 (CI: 1.13-1.32)), pneumonia (aRR = 1.38 (1.11-1.69)), urinary tract infection (aRR of 1.58 (CI: 1.28-1.92)) and sepsis (aRR = 1.18 (CI: 0.67-1.89)), but a reduced risk of cardiovascular events (aRR = 0.59 (CI: 0.41-0.82)). The aRR for 30-day mortality was 1.11 (CI: 0.97-1.27) for PD vs non-PD patients, and the aHR for 1-year mortality was 1.19 (CI: 1.09-1.30). The aRRs for fulfillment of all relevant quality indicators was about 1 for PD vs non-PD patients. CONCLUSION: Hip fracture patients with PD have a higher risk of infections and mortality within 30 days after surgery after adjustment for sex, age, and comorbidity. They do, however, receive comparable quality of in-hospital care after hip fracture compared to non-PD patients.

The epidemiology of desmoid tumors in Denmark.

INTRODUCTION/AIM: The epidemiology, demographic, clinical, treatment, and healthcare resource utilization (HRU) characteristics of desmoid tumor (DT) patients treated at two sarcoma centers in Denmark is described. METHODS: Using Danish health registers, we studied DT patients treated at two sarcoma centers between 2009 and 2018. For each patient, ten persons from the general population were randomly matched on birth year, sex, and region of residence. RESULTS: Of the 179 DT patients identified, 76% were female and the median patient age was 38 years at diagnosis (interquartile range: 31-50). An average annual incidence of DTs over the study period was 3.2 per 1000,000 individuals with the observed annual incidence of DTs ranging from 2.2 (2011) to 4.3 (2017) per 1000,000 individuals. No notable linear time trend in incidence was observed. Anatomical DT sites included extra-abdominal (49%), abdominal wall (40%), and intra-abdominal or retroperitoneal areas (8%). In total, 56% of patients were initially treated surgically. However, while 75% of patients diagnosed with DT between 2009 and 2014 were initially treated surgically, this was true for only 32% of patients diagnosed with DT between 2015 and 2018. A total of 56% of DT patients used chemotherapeutic agents, tyrosine kinase inhibitors, NSAIDs, opioids, antidepressants, or steroids at some point during the three years before their DT diagnoses. In contrast, 70% of surgically treated and 63% of non-surgically treated patients used one of these drugs in the subsequent three years, including NSAIDs (45% surgical vs. 33% non-surgical), opioids (39% surgical vs. 27% non-surgical), and steroids (22% surgical vs. 18% non-surgical). The average number of inpatient and outpatient visits, days of hospitalization, and additional surgical procedures were higher among DT patients than the comparison cohort. CONCLUSION: DTs are rare but have a large impact on patients' health, HRU, and medication utilization.

Socioeconomic status and use of analgesic drugs before and after primary hip arthroplasty: a population-based cohort study of 103,209 patients during 1996-2018.

Background and purpose - Total hip arthroplasty (THA) is an effective and common procedure. However, persistent pain and analgesic requirement up to 2 years after THA surgery are common. We examined the trends in the utilization of analgesics before and after THA, overall, and in relation to socioeconomic status (SES) in a populationbased cohort. Patients and methods - We used the Danish Hip Arthroplasty Register to identify 103,209 patients who underwent THA between 1996 and 2018. Data on prescriptions and SES markers was obtained from Danish medical databases. Prevalence rates of redeemed prescriptions for analgesics with 95% confidence intervals were calculated for 4 quarters before and 4 quarters after THA for the entire THA population, and by 3 SES markers (education, cohabiting status, and wealth). Results - Overall, the prevalence of analgesic use prior to surgery was 42% at 9-12 months and 59% at 0-3 months before the THA. The prevalence of analgesics reached its highest at 64% 0-3 months after THA but declined to 27% at 9-12 months after THA. Low education, living alone, and having low wealth (low SES) were associated with higher prevalence of analgesics use both before and after THA. Interpretation - 59% of patients used analgesics 0-3 months before surgery, which could indicate that THA might not be considered the last option for treatment and that surgery criteria might depend more on factors such as patient preferences or hip function. Moreover, health professionals should prioritize the use of a detailed plan when phasing out analgesics after THA to counteract unnecessary use, especially when treating patients with low SES.

Risk of mortality and reoperation in hip fracture patients undergoing cemented versus uncemented hemiarthroplasty : a population-based study from Danish National Registries.

AIMS: The aim of this study was to assess the association of mortality and reoperation when comparing cemented and uncemented hemiarthroplasty (HA) in hip fracture patients aged over 65 years. METHODS: This was a population-based cohort study on hip fracture patients using prospectively gathered data from several national registries in Denmark from 2004 to 2015 with up to five years follow-up. The primary outcome was mortality and the secondary outcome was reoperation. Hazard ratios (HRs) for mortality and subdistributional hazard ratios (sHRs) for reoperations are shown with 95% confidence intervals (CIs). RESULTS: A total of 17,671 patients with primary HA were identified (9,484 uncemented and 8,187 cemented HAs). Compared to uncemented HA, surgery with cemented HA was associated with an absolute risk difference of 0.4% for mortality within the period zero to one day after surgery and an adjusted HR of 1.70 (95% CI 1.22 to 2.38). After seven days, there was no longer any association, with an adjusted HR of 1.07 (95% CI 0.90 to 1.28). This continued until five years after surgery with a HR of 1.01 (95% CI 0.96 to 1.06). There was a higher proportion of reoperations due to any reason after five years in the uncemented group with 10.2% compared to the cemented group with 6.1%. This yielded an adjusted sHR of 0.65 (95% CI 0.57 to 0.75) and difference continued up until five years after the surgery, demonstrating a sHR of 0.70 (95% CI 0.59 to 0.83). CONCLUSION: In a non-selected cohort of hip fracture patients, surgery with cemented HA was associated with a higher relative mortality during the first postoperative day compared to surgery with uncemented HA, but there was no difference after seven days up until five years after. In contrast, surgery with cemented HA was associated with lower risk of reoperation up to five years postoperatively compared with surgery with uncemented HA. There was a higher relative mortality on the first postoperative day for cemented HA versus uncemented HA. There was no difference in mortality after seven days up until five years after surgery. There were 6.1% reoperations for cemented HA compared to 10.2% for uncemented HA after five years. Cite this article: Bone Joint J 2022;104-B(1):127-133.