Clinical features of polymyalgia rheumatica patients in Japan: Analysis of real-world data from 2015 to 2020

OBJECTIVES

To assess clinical features in patients with polymyalgia rheumatica (PMR) in Japan by the International Classification of Disease (ICD)-10 code assignment.

METHODS

Demographics, treatment patterns, and concomitant diseases (identified using ICD-10 code only) in patients who were assigned the PMR ICD-10 code M35.3 at least once between 1 January 2015 and 31 December 2020 were aggregated from a nationwide medical information database owned by the Health, Clinic, and Education Information Evaluation Institute.

RESULTS

The cumulative number of patients with PMR was 6325 (mean [standard deviation] age, 74.3 [11.4] years; male:female, 1:1.3). Most patients were >50 years (96.5%) with >33% between 70 and 79 years. Glucocorticoids were prescribed in ∼54% of patients within 30 days of PMR code assignment. All other drug types were prescribed in <5% of patients. Hypertension, diabetes mellitus, rheumatoid arthritis, and osteoporosis were noted in >25% and giant cell arteritis in 1% of patients. During the study period, 4075 patients were newly assigned the PMR code and 62% were prescribed glucocorticoids within 30 days.

CONCLUSIONS

This is the first retrospective real-world data analysis describing the clinical features of PMR in a large patient population from Japan. Further studies of prevalence, incidence, and clinical features are warranted in patients with PMR.

Polymyalgia rheumatica

Polymyalgia rheumatica is an inflammatory disease producing pain and stiffness, mainly in the shoulders and pelvic girdle, in people older than 50 years. Elevation of acute phase reactants is common due to the inflammatory nature of the disease. Since there are no specific diagnostic tests, diagnosis requires the exclusion of other diseases with similar presentations. Imaging has helped to identify the pathological substrate of polymyalgia rheumatica and it is increasingly used to support clinical diagnosis or to detect coexistent giant cell arteritis. Although polymyalgia rheumatica does not clearly impair survival or organ function, it can have a detrimental effect on quality of life. Glucocorticoids at 12·5-25·0 mg prednisone per day are effective in inducing remission in most individuals but, when tapered, relapses occur in 40-60% of those affected and side-effects are common. Assessment of disease activity can be difficult because pain related to common comorbidities such as osteoarthritis and tendinopathies, can return when glucocorticoids are reduced, and acute phase reactants are increased less during flares in individuals undergoing treatment or might increase for other reasons. The role of imaging in assessing disease activity is not yet completely defined. In the search for more efficient and safer therapies, tocilizumab and sarilumab have shown efficacy in randomised controlled trials and additional targeted therapies are emerging. However, judicious risk-benefit balance is essential in applying therapeutic innovations to people with polymyalgia rheumatica.

Unmet need in the treatment of polymyalgia rheumatica and giant cell arteritis

For decades, aside from prednisone and the occasional use of immune suppressive drugs such as methotrexate, there was little to offer patients with polymyalgia rheumatica (PMR) and giant cell arteritis (GCA). However, there is a great interest in various steroid sparing treatments in both these conditions. This paper aims to provide an overview of our current knowledge of PMR and GCA, examining their similarities and distinctions in terms of clinical presentation, diagnosis, and treatment, with emphasis placed on reviewing recent and ongoing research efforts on emerging treatment. Multiple recent and ongoing clinical trials are demonstrating new therapeutics that will provide benefit and contribute to the evolution of clinical guidelines and standard of care for patients with GCA and/or PMR.

An update on polymyalgia rheumatica

Polymyalgia rheumatica (PMR) is the most common inflammatory rheumatic disease affecting people older than 50 years and is 2-3 times more common in women. The most common symptoms are pain and morning stiffness in the shoulder and pelvic girdle and the onset may be acute or develop over a few days to weeks. General symptoms such as fatigue, fever and weight loss may occur, likely driven by systemic IL-6 signalling. The pathology includes synovial and periarticular inflammation and muscular vasculopathy. A new observation is that PMR may appear as a side effect of cancer treatment with checkpoint inhibitors. The diagnosis of PMR relies mainly on symptoms and signs combined with laboratory markers of inflammation. Imaging modalities including ultrasound, magnetic resonance imaging and positron emission tomography with computed tomography are promising new tools in the investigation of suspected PMR. However, they are still limited by availability, high cost and unclear performance in the diagnostic workup. Glucocorticoid (GC) therapy is effective in PMR, with most patients responding promptly to 15-25 mg prednisolone per day. There are challenges in the management of patients with PMR as relapses do occur and patients with PMR may need to stay on GC for extended periods. This is associated with high rates of GC-related comorbidities, such as diabetes and osteoporosis, and there are limited data on the use of disease-modifying antirheumatic drugs and biologics as GC sparing agents. Finally, PMR is associated with giant cell arteritis that may complicate the disease course and require more intense and prolonged treatment.

Fracture Risk and Its Prevention Patterns in Korean Patients with Polymyalgia Rheumatica: a Retrospective Cohort Study

BACKGROUND

To evaluate the incidence of fractures and fracture risk factors in Korean patients with polymyalgia rheumatica (PMR).

METHODS

All PMR patients who visited a rheumatology clinic at a tertiary referral hospital between March 2005 and March 2018 were retrospectively assessed. We estimated bone mineral density (BMD) screening rate within 6 months of the first visit and classified the patients according to the performance and results of BMD screening. Incidence rates (IRs) of fractures were calculated in each group and risk factors for fractures were identified using Poisson regression analysis.

RESULTS

A total of 95 PMR patients with median (interquartile range) age of 64.0 (56.0-72.0) years were included. Baseline BMD was assessed in only 55.8% of these patients (n = 53); 24 patients with osteoporosis, 20 with osteopenia, and 9 with normal BMD. During 433.1 person-years (PYs) of observation, 17 fractures occurred in 12 patients (IR, 3.93 [95% confidence interval (CI), 2.46-6.26]/100 PYs); 8.32 (95% CI, 4.09-16.90)/100 PYs in the osteopenia group, 3.40 (95% CI, 1.30-8.90)/100 PYs in the osteoporosis group, and 3.37 (95% CI, 1.53-7.39)/100 PYs in the no BMD test group. Risk factors for fractures were female sex, advanced age (≥ 65 years), longer follow-up duration, initial glucocorticoid dose ≥ 10 mg/day, and higher cumulative glucocorticoid dose over the first 6 months.

CONCLUSION

The incidence rate of fractures in Korean patients with PMR was 3.93/100 PYs. Female sex, advanced age, longer follow-up duration, and increased glucocorticoid dose are risk factors for osteoporotic fracture.