Unclear reporting of secondary outcome in randomized trial of Lv et al.

To the editor: We read with interest the randomized controlled trial published by Lv and colleagues [1]. This single-centre trial randomized 117 patients admitted to the intensive care unit with sepsis to moderate-dose vitamin C (total daily dose not explicitly stated, but likely 6 g) or placebo. The trial found a statistically significant difference in 28-day mortality (15/61 [24.6%] in vitamin C group vs. 24/56 [42.9%] in the placebo group, p = 0.002).

Change in sepsis-related organ failure assessment (SOFA) score [2] in the first 72 h after intensive care unit admission was a secondary outcome; higher SOFA scores denote worse organ dysfunction and are associated with increased risk of mortality. Comparable baseline SOFA scores were reported (mean ± standard deviation, 8.6 ± 2.9 [vitamin C] vs. 8.9 ± 3.1 [placebo]); however, reporting of follow-up data is inconsistent. The results text and Table 2 indicate that patients receiving vitamin C had greater organ failure at 72 h than controls (median [quartile 1, quartile 3] SOFA score 4.2 [1.2, 6.6] vs. 2.1 [1.1, 4.3], p = 0.001). Conversely, the results and conclusion of the abstract, along with the discussion and conclusion of the paper, suggest that patients receiving vitamin C had a greater change in 72-h vs. baseline SOFA score compared to controls (change in SOFA score, as reported in the abstract, 4.2 vs. 2.1, with values implied to be reductions and the larger reduction in the vitamin C group).

The issue is important to resolve, both for the interpretation of this trial and of published meta-analyses, which have assumed that the SOFA data reported by Lv and colleagues refer to change in SOFA at 72 h [3].

We attempted to contact the authors on two occasions to clarify their data, with no success.