Rheumatoid Arthritis: Trends in Antirheumatic Drug Use, C-reactive Protein Levels, and Surgical Burden

Development of a Machine Learning Model to Predict the Use of Surgery in Patients With Rheumatoid Arthritis

OBJECTIVE

One in five patients with rheumatoid arthritis (RA) rely on surgery to restore joint function. However, variable response to disease-modifying antirheumatic drugs (DMARDs) complicates surgical planning, and it is difficult to predict which patients may ultimately require surgery. We used machine learning to develop predictive models for the likelihood of undergoing an operation related to RA and which type of operation patients who require surgery undergo.

METHODS

We used electronic health record data to train two extreme gradient boosting machine learning models. The first model predicted patients' probabilities of undergoing surgery ≥5 years after their initial clinic visit. The second model predicted whether patients who underwent surgery would undergo a major joint replacement versus a less intensive procedure. Predictors included demographics, comorbidities, and medication data. The primary outcome was model discrimination, measured by area under the receiver operating characteristic curve (AUC).

RESULTS

We identified 5,481 patients, of whom 278 (5.1%) underwent surgery. There was no significant difference in the frequency of DMARD or steroid prescriptions between patients who did and did not have surgery, though nonsteroidal anti-inflammatory drug prescriptions were more common among patients who did have surgery (P = 0.03). The model predicting use of surgery had an AUC of 0.90 ± 0.02. The model predicting type of surgery had an AUC of 0.58 ± 0.10.

CONCLUSIONS

Predictive models using clinical data have the potential to facilitate identification of patients who may undergo rheumatoid-related surgery, but not what type of procedure they will need. Integrating similar models into practice has the potential to improve surgical planning.

Effects of biologics on reducing the risks of total knee replacement and total hip replacement in rheumatoid arthritis

OBJECTIVES

RA damages the joints and increases the risks of total knee replacement (TKR) and total hip replacement (THR). However, the benefits of biologics in preventing TKR or THR remain unclear.

METHODS

This retrospective nationwide study used the 2000-2013 claims-based National Health Insurance dataset. Biologics are reimbursed for refractory cases. The risks of TKR and THR in the biologic cohort were compared with those of age- and sex-matched csDMARD cohort. A multivariate Cox regression model was used to investigate the benefits of bDMARDs for TKR and THR.

RESULTS

TKR was performed in 5979 biologic cases and 11,958 matched controls, of which 249(4.16%) and 871(7.28%) cases received TKR, respectively. THR was performed in 6245 biologic cases and 12,490 matched controls, of which 159(2.55%) and 516(4.13%) cases had THR, respectively. The biologic cohort had significantly lower incidence rates of TKR (11.73 vs. 16.33/1000 person-years, P < 0.001) and THR (7.09 vs. 9.16/1000 person-years, P < 0.001). After adjustment for confounding factors, the regular bDMARD subgroup (average dose >0.95 defined daily dose/day) had significantly lower risks of TKR (aHR: 0.55, 95% CI: 0.38-0.81) and THR (aHR: 0.63, 95% CI: 0.40-0.98). Those without methotrexate use, with steroid use, with biologic switch, and overlapping antiphospholipid syndrome had significantly higher risks of TKR and THR.

CONCLUSIONS

Compared with the csDMARD cohort, the risks of TKR and THR in the bDMARD cohort were the same as those in the low to moderate dose subgroups and significantly lower in those with regular bDMARD use.

Has the incidence of total joint arthroplasty in rheumatoid arthritis decreased in the era of biologics use? A population-based cohort study

OBJECTIVES

To determine whether the introduction of biological disease-modifying anti-rheumatic drugs (bDMARDs) was associated with reduced incidences of total hip and knee arthroplasty (THA/TKA) among patients with rheumatoid arthritis (RA) compared with osteoarthritis (OA).

METHODS

Using a population-based cohort in British Columbia, Canada, RA and OA patients diagnosed between 1995-2007 were divided into semi-annual cohorts according to diagnosis date. For each cohort, we calculated 8-year incidence rates of THA and TKA. We compared levels and trends of THA/TKA incidence in RA/OA patients diagnosed during pre-bDMARDs (1995-2001) and post-bDMARDs (2003-2007) periods using interrupted time-series analysis, adjusting for baseline characteristics. Adjusted 8-year TJA incidence estimated for RA/OA cohorts diagnosed five years after bDMARDs introduction were compared with expected rates assuming no bDMARDs introduction, based on extrapolation of pre-bDMARDs trends.

RESULTS

We identified 60,227 RA and 288,260 OA incident cases. For cohorts diagnosed pre-bDMARDs, 8-year THA/TKA incidence rates increased over time in both RA and OA. For cohorts diagnosed post-bDMARDs, these rates decreased over time in RA but continued to increase for OA. For RA, differences between the post- and pre-bDMARDs secular trends in incidence rates were -0.49 (p = 0.002) for THA and -0.36 (p = 0.003) for TKA, compared to + 0.40 (p = 0.006) and +0.54 (p < 0.001), respectively, for OA. For RA cohorts diagnosed five years after bDMARDs introduction, 8-year incidence were 26.9% and 12.6% lower for THA and TKA, respectively, than expected rates. In contrast, corresponding rates in OA were higher by 11.7% and 16.6%, respectively.

CONCLUSION

Arthritis onset after bDMARDs introduction is associated with a significant reduction in THA/TKA incidence in RA, but not in OA. The reduction reflects a significant improvement in RA treatment during the biological era.

Orthopedic Surgery in Rheumatoid Arthritis: Results from the Spanish National Registry of Hospitalized Patients over 17 Years

OBJECTIVE

To analyze the trend of orthopedic surgery (OS) rates on patients with rheumatoid arthritis (RA).

METHODS

Retrospective observational study based on information provided by the Spanish National System of Hospital Data Surveillance. All hospitalizations of patients with RA for orthopedic surgery [total hip arthroplasty (THA), total knee arthroplasty (TKA), arthrodesis, and upper limb arthroplasty (ULA)] during 1999-2015 were analyzed. The age-adjusted rate was calculated. Generalized linear models were used for trend analysis.

RESULTS

There were 21,088 OS in patients over 20 years of age (77.9% women). OS rate adjusted by age was 754.63/100,000 RA patients/year (women 707.4, men 861.1). Neither an increasing nor a decreasing trend was noted for the total OS. However, trend and age interacted, so in the age ranges 20-40 years and 40-60 years, an annual reduction of 2.69% and 2.97%, respectively, was noted. In the age ranges over 80 years and 60-80 years, we noted an annual increase of 5.40% and 1.09%, respectively. The average age at time of OS increased 5.5 years during the period analyzed. For specific surgeries, a global annual reduction was noted in rates for arthrodesis. In THA, there was an annual reduction in patients under 80 years. In TKA and ULA, there was an annual reduction in patients under 60 years.

CONCLUSION

Although the overall OS rate has not changed, there is a decrease in the rate of arthrodesis at all ages, THA in patients under 80 years of age, as well as TKA and ULA in patients under 60 years of age.

The impact of hindfoot deformities for the recurrence of hallux valgus after joint-preserving surgeries for rheumatoid forefoot deformities

BACKGROUND

Recurrence of hallux valgus (HV) is a common complication after forefoot surgery for rheumatoid forefoot deformities. The aim of this study is to evaluate the impact of hindfoot malalignment on recurrence.

METHODS

This was a retrospective observational study designed to analyze the radiographic outcomes of 87 feet in 64 patients with rheumatoid arthritis treated with a joint-preserving surgery for HV deformity. Differences in hindfoot alignment preoperatively between the recurrence and nonrecurrence groups was compared.

RESULTS

There were no significant differences in hindfoot alignment preoperatively between groups. To estimate the impact of technical problems, the HV and intermetatarsal angles measured from radiographs 3 months postoperatively were compared between groups. The HV angles in the recurrence group were significantly larger than those in the nonrecurrence group (p=0.02).

CONCLUSIONS

There were no significant differences between preoperative hindfoot malalignment and postoperative recurrence of HV in rheumatoid forefoot surgeries.

Development of heart failure in patients with rheumatoid arthritis: A Danish population-based study

BACKGROUND

To investigate the incidence of heart failure (HF) and ischaemic heart disease (IHD) in different time spans following incident rheumatoid arthritis (RA) and, furthermore, to investigate the impact of IHD on the development of HF and the impact of different treatment era of RA.

MATERIALS AND METHODS

This matched cohort study used nationwide, prospectively collected data. From the total Danish population of approximately 5.7 million inhabitants, we identified 51 859 patients (between 1995 and July 2016) with incident RA and a sex- and age-matched cohort from the general population (256 653 persons).

RESULTS

The hazard ratio (HR) for HF among RA patients compared with persons from comparison cohort was 2.28 within the first year of index date, 1.39 within the 1-5 years of index date and 1.38 within the 5-10 years of index date. No difference was identified regarding different treatment era of RA. For IHD, the subdistribution hazard ratio (sHR) was 1.93 within the first year of index date, 1.26 within the 1-5 years of index date and 1.31 within the 5-10 years of index date. Coronary revascularization was also more common within the first year after diagnosis of RA. An increased risk of percutaneous coronary intervention and coronary artery bypass grafting within 10 years following the RA diagnosis was observed. HR for new onset of HF in RA without IHD was 1.23, while the HR for new onset of HF in patients with RA and IHD was 2.06.

CONCLUSIONS

Rheumatoid arthritis patients had higher rates of HF and IHD throughout the entire observation period compared to the comparison cohort. RA was associated with a larger risk of developing HF.

Aerobic capacity over 16 years in patients with rheumatoid arthritis: Relationship to disease activity and risk factors for cardiovascular disease

The aim of this study was to analyse the change in aerobic capacity from disease onset of rheumatoid arthritis (RA) over 16.2 years, and its associations with disease activity and cardiovascular risk factors. Twenty-five patients (20 f/5 m), diagnosed with RA 1995-2002 were tested at disease onset and after mean 16.2 years. Parameters measured were: sub-maximal ergometer test for aerobic capacity, functional ability, self-efficacy, ESR, CRP and DAS28. At follow-up, cardiovascular risk factors were assessed as blood lipids, glucose concentrations, waist circumference, body mass index (BMI), body composition, pulse wave analysis and carotid intima-media thickness. Aerobic capacity [median (IQR)] was 32.3 (27.9-42.1) ml O₂/kg x min at disease onset, and 33.2 (28.4-38.9) at follow-up (p>0.05). Baseline aerobic capacity was associated with follow-up values of: BMI (r_s = -.401, p = .047), waist circumference (r_s = -.498, p = .011), peripheral pulse pressure (r_s = -.415, p = .039) self-efficacy (r_s = .420, p = .037) and aerobic capacity (r_s = .557, p = .004). In multiple regression models adjusted for baseline aerobic capacity, disease activity at baseline and over time predicted aerobic capacity at follow-up (AUC DAS28, 0-24 months; β = -.14, p = .004). At follow-up, aerobic capacity was inversely associated with blood glucose levels (r_s = -.508, p = .016), BMI (r_s = -.434, p = .030), body fat% (r_s = -.419, p = .037), aortic pulse pressure (r_s = -.405, p = .044), resting heart rate (r_s = -.424, p = .034) and self-efficacy (r_s = .464, p = .020) at follow-up. We conclude that the aerobic capacity was maintained over 16 years. High baseline aerobic capacity associated with favourable measures of cardiovascular risk factors at follow-up. Higher disease activity in early stages of RA predicted lower aerobic capacity after 16.2 years.

Incidence of hip and knee replacement in patients with rheumatoid arthritis following the introduction of biological DMARDs: an interrupted time-series analysis using nationwide Danish healthcare registers

OBJECTIVES

To study the impact of the introduction of biological disease-modifying anti-rheumatic drugs (bDMARDs) and associated rheumatoid arthritis (RA) management guidelines on the incidence of total hip (THR) and knee replacements (TKR) in Denmark.

METHODS

Nationwide register-based cohort and interrupted time-series analysis. Patients with incident RA between 1996 and 2011 were identified in the Danish National Patient Register. Patients with RA were matched on age, sex and municipality with up to 10 general population comparators (GPCs). Standardised 5-year incidence rates of THR and TKR per 1000 person-years were calculated for patients with RA and GPCs in 6-month periods. Levels and trends in the pre-bDMARD (1996-2001) were compared with the bDMARD era (2003-2016) using segmented linear regression interrupted by a 1-year lag period (2002).

RESULTS

We identified 30 404 patients with incident RA and 297 916 GPCs. In 1996, the incidence rate of THR and TKR was 8.72 and 5.87, respectively, among patients with RA, and 2.89 and 0.42 in GPCs. From 1996 to 2016, the incidence rate of THR decreased among patients with RA, but increased among GPCs. Among patients with RA, the incidence rate of TKR increased from 1996 to 2001, but started to decrease from 2003 and throughout the bDMARD era. The incidence of TKR increased among GPCs from 1996 to 2016.

CONCLUSION

We report that the incidence rate of THR and TKR was 3-fold and 14-fold higher, respectively among patients with RA compared with GPCs in 1996. In patients with RA, introduction of bDMARDs was associated with a decreasing incidence rate of TKR, whereas the incidence of THR had started to decrease before bDMARD introduction.

Venous thromboembolism and risk of cancer in patients with rheumatoid arthritis

Essentials Can venous thromboembolism (VTE) in rheumatoid arthritis (RA) patients be marker of cancer? RA patients with VTE and comparison cohorts from population-based registries were compared. Increased risk of cancer in RA patients with VTE during the first year of VTE was observed. Risk of cancer in RA patients was increased also during the longer period following VTE.

SUMMARY

Background It is unknown whether venous thromboembolism (VTE) in rheumatoid arthritis (RA) patients can be a marker of occult cancer. Objectives To examine risk of cancer subsequent to VTE among RA patients compared with risk of cancer in an RA cohort without VTE and in a general population without RA and without VTE. Patients/Methods All RA patients with a first-time diagnosis of VTE (index date) during 1978-2013 and comparison cohorts were identified from population-based registries in Denmark. Results We identified three cohorts: 2497 RA patients with VTE, 11 672 RA patients without VTE and 12 730 persons from the general population. The cumulative incidence of cancer within the first year of the index date was 3.2% among RA with VTE, 2.2% among RA without VTE, and 2.0% in the general population cohort. Incidence rate ratios (IRRs) were 1.79 (95% confidence interval [CI], 1.37-2.33) for RA patients with VTE vs. RA patients without VTE and 2.12 (95% CI, 1.63-2.76) for RA patients with VTE vs. the general population. The IRR of cancer at > 1 to 36 years from the index date among RA patients with VTE was 1.16 (95% CI, 1.00-1.34) compared with the RA patients without VTE and 1.33 (95% CI, 1.15-1.53) compared with the general population. Conclusions We found an increased risk of cancer in RA patients with VTE during the first year following VTE and also during the longer follow-up period. Thus, VTE may not only be a result of inflammation and immunological dysfunctions associated with RA, but may also be a marker for occult cancer.

Use of Disease-modifying Antirheumatic Drugs for Inflammatory Arthritis in US Veterans: Effect of Specialty Care and Geographic Distance

Objective.

To evaluate the effect of access to and distance from rheumatology care on the use of disease-modifying antirheumatic drugs (DMARD) in US veterans with inflammatory arthritis (IA).

Methods.

Provider encounters and DMARD dispensations for IA (rheumatoid arthritis, psoriatic arthritis, and ankylosing spondylitis) were evaluated in national Veterans Affairs (VA) datasets between January 1, 2015, and December 31, 2015.

Results.

Among 12,589 veterans with IA, 23.5% saw a rheumatology provider. In the general IA population, 25.3% and 13.6% of veterans were exposed to a synthetic DMARD (sDMARD) and biologic DMARD (bDMARD), respectively. DMARD exposure was 2.6- to 3.4-fold higher in the subpopulation using rheumatology providers, compared to the general IA population. The distance between veterans’ homes and the closest VA rheumatology site was < 40 miles (Near) for 55.9%, 40–99 miles (Intermediate) for 31.7%, and ≥ 100 miles (Far) for 12.4%. Veterans in the Intermediate and Far groups were less likely to see a rheumatology provider than veterans in the Near group (RR = 0.72 and RR = 0.49, respectively). Exposure to bDMARD was 34% less frequent in the Far group than the Near group. In the subpopulation who used rheumatology care, the bDMARD exposure discrepancy did not persist between distance groups.

Conclusion.

Use of rheumatology care and DMARD was low for veterans with IA. DMARD exposure was strongly associated with rheumatology care use. Veterans in the general IA population living far from rheumatology sites accessed rheumatology care and bDMARD less frequently than veterans living close to rheumatology sites.

Decreased Cardiovascular Mortality in Patients with Incident Rheumatoid Arthritis (RA) in Recent Years: Dawn of a New Era in Cardiovascular Disease in RA?

OBJECTIVE

To assess trends in cardiovascular (CV) mortality in patients with incident rheumatoid arthritis (RA) in 2000-07 versus the previous decades, compared with non-RA subjects.

METHODS

The study population consisted of Olmsted County, Minnesota, USA residents with incident RA (age ≥ 18 yrs, 1987 American College of Rheumatology criteria was met in 1980-2007) and non-RA subjects from the same underlying population with similar age, sex, and calendar year of index. All subjects were followed until death, migration, or December 31, 2014. Followup was truncated for comparability. Aalen-Johansen methods were used to estimate CV mortality rates, adjusting for competing risk of other causes. Cox proportional hazards models were used to compare CV mortality by decade.

RESULTS

The study included 813 patients with RA and 813 non-RA subjects (mean age 55.9 yrs; 68% women for both groups). Patients with incident RA in 2000-07 had markedly lower 10-year overall CV mortality (2.7%, 95% CI 0.6-4.9%) and coronary heart disease (CHD) mortality (1.1%, 95% CI 0.0-2.7%) than patients diagnosed in 1990-99 (7.1%, 95% CI 3.9-10.1% and 4.5%, 95% CI 1.9-7.1%, respectively; HR for overall CV death: 0.43, 95% CI 0.19-0.94; CHD death: HR 0.21, 95% CI 0.05-0.95). This improvement in CV mortality persisted after accounting for CV risk factors. Ten-year overall CV mortality and CHD mortality in 2000-07 RA incidence cohort was similar to non-RA subjects (p = 0.95 and p = 0.79, respectively).

CONCLUSION

Our findings suggest significantly improved overall CV mortality, particularly CHD mortality, in patients with RA in recent years. Further studies are needed to examine the reasons for this improvement.