Comparison of the therapeutic effects of 15 mg and 30 mg initial dosage of prednisolone daily in patients with subacute thyroiditis: protocol for a multicenter, randomized, open, parallel control study.

Background: Subacute thyroiditis (SAT) is the most common cause of thyroid pain. Several clinical guidelines recommend that patients who fail to respond to full doses of non-steroidal anti-inflammatory drugs (NSAIDs) should be treated instead with oral corticosteroid therapy. However, albeit strong recommendations, the treatment protocol is based on low-quality evidence and high-quality clinical trials are lacking with respect to the optimal initiation dosage and usage of corticosteroid. We aimed to evaluate whether 15 mg/day of prednisolone (PSL) as the initial dosage could provide non-inferiority effectiveness but with lower risk and more safety compared with 30 mg/day of PSL as the initial dosage.

Methods/design: This is a multicenter, open-label, randomized, parallel trial that will be conducted at five academic hospitals in China. A total of 90 adult patients diagnosed with SAT who present moderate to severe pain or fail to respond to full doses of NSAIDs will be randomly assigned with a 1:1 ratio to the low initial PSL dosage group (15 mg daily) and standard initial PSL dosage group (30 mg daily). The primary endpoint is the time period (days) required for PSL treatment (including PSL treatment for recurrence).

Discussion: Our randomized controlled trial will try to determine the optimal protocol in the treatment of SAT by providing high-quality evidence.

Trials Registration: Chinese Clinical Trial Register, ChiCTR1900023884. Registered on 15 June 2019.