Real-world implications of IMACS malignancy screening guidelines for idiopathic inflammatory myopathies: An evaluation of compliance and economic impact at a tertiary referral center.

AIM: An inaugural set of consensus guidelines for malignancy screening in idiopathic inflammatory myopathy (IIM) were recently published by an international working group. These guidelines propose different investigation strategies based on "high", "intermediate" or "standard" malignancy risk groups. This study compares current malignancy screening practices at an Australian tertiary referral center with the recommendations outlined in these guidelines. METHODS: We conducted a retrospective analysis of newly diagnosed IIM patients. Relevant demographic and clinical data regarding malignancy screening were recorded. Existing practice was compared with the guidelines using descriptive statistics; costs were calculated using the Australian Medicare Benefit Schedule. RESULTS: Of the 47 patients identified (66% female, median age: 63 years [IQR: 55.5-70], median disease duration: 4 years [IQR: 3-6]), only one had a screening-detected malignancy. Twenty patients (43%) were at high risk, while 20 (43%) were at intermediate risk; the remaining seven (15%) had IBM, for which the proposed guidelines do not recommend screening. Only three (6%) patients underwent screening fully compatible with International Myositis Assessment and Clinical Studies recommendations. The majority (N = 39, 83%) were under-screened; the remaining five (11%) overscreened patients had IBM. The main reason for guideline non-compliance was the lack of repeated annual screening in the 3 years post-diagnosis for high-risk individuals (0% compliance). The mean cost of screening was substantially lower than those projected by following the guidelines ($481.52 [SD 423.53] vs $1341 [SD 935.67] per patient), with the highest disparity observed in high-risk female patients ($2314.29/patient). CONCLUSION: Implementation of the proposed guidelines will significantly impact clinical practice and result in a potentially substantial additional economic burden.

Diagnosing and characterizing inflammatory myopathies at an Australian tertiary public hospital: Resource utilization and direct healthcare costs.

AIM: To determine the direct health service costs and resource utilization associated with diagnosing and characterizing idiopathic inflammatory myopathies (IIMs), and to assess for limitations and diagnostic delay in current practice. METHODS: A retrospective, single-center cohort analysis of all patients diagnosed with IIMs between January 2012 and December 2021 in a large tertiary public hospital was conducted. Demographics, resource utilization and costs associated with diagnosing IIM and characterizing disease manifestations were identified using the hospital's electronic medical record and Health Intelligence Unit, and the Medicare Benefits Schedule. RESULTS: Thirty-eight IIM patients were identified. IIM subtypes included dermatomyositis (34.2%), inclusion body myositis (18.4%), immune-mediated necrotizing myopathy (18.4%), polymyositis (15.8%), and anti-synthetase syndrome (13.2%). The median time from symptom onset to diagnosis was 212 days (IQR: 118-722), while the median time from hospital presentation to diagnosis was 30 days (8-120). Seventy-six percent of patients required emergent hospitalization during their diagnosis, with a median length of stay of 8 days (4-15). The average total cost of diagnosing IIM was $15 618 AUD (STD: 11331) per patient. Fifty percent of patients underwent both MRI and EMG to identify affected muscles, 10% underwent both pan-CT and PET-CT for malignancy detection, and 5% underwent both open surgical and percutaneous muscle biopsies. Autoimmune serology was unnecessarily repeated in 37% of patients. CONCLUSION: The diagnosis of IIMs requires substantial and costly resource use; however, our study has identified potential limitations in current practice and highlighted the need for streamlined diagnostic algorithms to improve patient outcomes and reduce healthcare-related economic burden.