What is the prognosis for a 66‑year‑old man with a 16‑year history of dermatomyositis on chronic prednisone who now has bilateral partial Achilles tendon tears?

Prognosis of Dermatomyositis with Bilateral Achilles Tendon Tears on Chronic Prednisone

The prognosis for this patient is guarded, with significant concerns for persistent disability and ongoing complications from both the underlying dermatomyositis and chronic corticosteroid use, particularly given the development of bilateral Achilles tendon tears which represent a serious steroid-induced complication. 1

Disease-Related Mortality and Morbidity

Overall survival in dermatomyositis shows disease-related mortality of at least 10%, primarily from associated malignancy and pulmonary complications. 2 Given this patient's 16-year disease duration, the risk of malignancy-associated dermatomyositis remains a concern and requires ongoing surveillance. 3

Key Mortality Factors

• Pulmonary complications represent a major cause of death in dermatomyositis patients 2
• Infection risk is elevated, with a 5% mortality rate specifically attributed to infections in treated dermatomyositis patients 4
• Cardiac involvement, if present, significantly worsens prognosis 3

Functional Prognosis and Disability

Despite treatment, 80% of dermatomyositis patients have a polycyclic or chronic continuous disease course, with only 20% achieving sustained remission off medications. 2

Expected Functional Outcomes

• 65% of patients achieve normal muscle strength at long-term follow-up 2
• Only 34% have no or slight disability, indicating that the majority experience persistent functional limitations 2
• Male sex is associated with worse disability (OR 3.1), which is relevant for this patient 2
• Higher age predicts persistent muscle weakness (OR 3.6), placing this 66-year-old at increased risk 2
• Many patients are left with residual weakness even after disease control 3

Corticosteroid-Related Complications

The bilateral Achilles tendon tears represent a serious manifestation of long-term corticosteroid toxicity, which is a major cause of morbidity in dermatomyositis patients. 1

Steroid-Induced Complications Already Present

• Tendon rupture (bilateral Achilles tears in this case) represents severe soft tissue damage from chronic prednisone 1
• Osteoporosis and compression fractures are primary adverse outcomes from prolonged corticosteroid use 1
• Avascular necrosis risk is elevated 1
• Corticosteroid-induced myopathy may compound the underlying disease-related weakness 1

Additional Steroid Complications to Monitor

• Weight gain, hypertension, diabetes, dyslipidemia, and cataracts are common with long-term use 1

Disease Course Expectations

The most significant improvement in muscle strength typically occurs within the first 6-12 months following initial treatment, suggesting this patient is now in a maintenance phase after 16 years. 4

Ongoing Treatment Requirements

• 41% of patients with favorable clinical outcomes still require ongoing immunosuppressive therapy 2
• 80% of patients require continued medication due to polycyclic or chronic continuous disease course 2
• The patient will likely need indefinite immunosuppression given the disease duration 1

Specific Concerns for This Patient

Tendon Healing Prognosis

• Bilateral Achilles tendon tears on chronic prednisone have poor healing potential due to impaired collagen synthesis and tissue repair mechanisms
• Surgical repair, if needed, carries higher complication rates in immunosuppressed patients on corticosteroids
• Rehabilitation will be prolonged and functional recovery may be incomplete

Mobility and Quality of Life Impact

• Bilateral Achilles involvement severely limits ambulation, stair climbing, and activities of daily living
• Risk of falls and further injury is substantially elevated during the recovery period
• Quality of life is significantly impaired, as only 16% of dermatomyositis patients achieve normal physical function scores 2

Risk Stratification

Poor Prognostic Indicators Present

• Male sex (associated with worse disability) 2
• Age 66 years (higher age predicts persistent weakness) 2
• 16-year disease duration with ongoing treatment requirements 2
• Severe corticosteroid complication (bilateral tendon tears) indicating cumulative steroid toxicity 1

Monitoring Requirements

• Regular assessment of muscle strength and functional capacity 5
• Surveillance for malignancy given the dermatomyositis diagnosis 3
• Monitoring for additional steroid complications including bone density assessment 1
• Evaluation for cardiac and pulmonary involvement which impact mortality 3, 2
• Infection surveillance given immunosuppression and infection-related mortality risk 4

Treatment Optimization Considerations

Steroid-sparing agents should be optimized to minimize further corticosteroid exposure and prevent additional complications. 1

• Consider methotrexate, azathioprine, or mycophenolate mofetil if not already maximized 1, 4
• IVIG therapy may allow corticosteroid dose reduction 4
• Calcium, vitamin D, and bisphosphonates are essential for bone protection 1
• Pneumocystis prophylaxis should be considered if prednisone ≥20 mg for ≥4 weeks 1

Summary of Prognosis

This patient faces a guarded prognosis with high likelihood of persistent disability, ongoing medication requirements, and risk of additional complications. The bilateral Achilles tendon tears represent a sentinel event indicating severe cumulative steroid toxicity after 16 years of treatment. While disease-related mortality is approximately 10%, the quality of life and functional outcomes are concerning, with the majority of patients experiencing persistent limitations despite treatment. 2, 1 The combination of male sex, advanced age, long disease duration, and severe steroid complications places this patient at the higher end of risk for poor functional outcomes. 2