Heterogeneity of treatment effect of higher dose dexamethasone by geographic region (Europe vs. India) in patients with COVID-19 and severe hypoxemia – a post hoc evaluation of the COVID STEROID 2 trial

Background In the COVID-STEROID 2 trial there was suggestion of heterogeneity of treatment effects (HTE) between patients enrolled from Europe vs. India on the primary outcome. Whether there was HTE for the remaining patient-centred outcomes is unclear. Methods In this post hoc analysis of the COVID-STEROID 2 trial, which compared 12 mg vs. 6 mg dexamethasone in adults with COVID-19 and severe hypoxemia, we evaluated HTE by geographical region (Europe vs. India) for secondary outcomes with analyses adjusted for stratification variables. Results are presented as risk differences (RDs) or mean differences (MDs) with 99% confidence intervals (CIs) and P-values from interaction tests. Findings There were differences in mortality at day 28 (RD for Europe −8.3% (99% CI: −17.7 to 1.0) vs. India 0.1% (99% CI: −10.0 to 10.0)), mortality at day 90 (RD for Europe −7.4% (99% CI: −17.1 to 2.0) vs. India −1.4% (99% CI: −12.8 to 9.8)), mortality at day 180 (RD for Europe −6.7% (99% CI: −16.4 to 2.9) vs. India −1.0% (99% CI: −12.3 to 10.3)), and number of days alive without life support at day 90 (MD for Europe 6.1 days (99% CI: −1.3 to 13.4) vs. India 1.7 days (99% CI: −8.4 to 11.8)). For serious adverse reactions, the direction was reversed (RD for Europe −1.0% (99% CI: −7.1 to 5.2) vs. India −5.3% (99% CI: −16.2 to 5.0). Interpretation Our analysis suggests higher dose dexamethasone may have less beneficial effects for patients in India as compared with those in Europe; however, the evidence is weak, and this could represent a chance finding.
Background: In the COVID-STEROID 2 trial there was suggestion of heterogeneity of treatment effects (HTE) between patients enrolled from Europe vs. India on the primary outcome. Whether there was HTE for the remaining patient-centred outcomes is unclear. Methods: In this post hoc analysis of the COVID-STEROID 2 trial, which compared 12 mg vs. 6 mg dexamethasone in adults with COVID-19 and severe hypoxemia, we evaluated HTE by geographical region (Europe vs. India) for secondary outcomes with analyses adjusted for stratification variables. Results are presented as risk differences (RDs) or mean differences (MDs) with 99% confidence intervals (CIs) and P-values from interaction tests. Findings: There were differences in mortality at day 28 (RD for Europe −8.3% (99% CI: −17.7 to 1.0) vs. India 0.1% (99% CI: −10.0 to 10.0)), mortality at day 90 (RD for Europe −7.4% (99% CI: −17.1 to 2.0) vs. India −1.4% (99% CI: −12.8 to 9.8)), mortality at day 180 (RD for Europe −6.7% (99% CI: −16.4 to 2.9) vs. India −1.0% (99% CI: −12.3 to 10.3)), and number of days alive without life support at day 90 (MD for Europe 6.1 days (99% CI: −1.3 to 13.4) vs. India 1.7 days (99% CI: −8.4 to 11.8)). For serious adverse reactions, the direction was reversed (RD for Europe −1.0% (99% CI: −7.1 to 5.2) vs. India −5.3% (99% CI: −16.2 to 5.0). Interpretation: Our analysis suggests higher dose dexamethasone may have less beneficial effects for patients in India as compared with those in Europe; however, the evidence is weak, and this could represent a chance finding. Funding: None for this analysis. The COVID STEROID 2 trial was funded by The Novo Nordisk Foundation and supported by Rigshospitalet's Research Council.