Background Systemic corticosteroid administration for severe acute exacerbations of COPD (AECOPD) reduces the duration of hospital stays. Corticosteroid-sparing regimens have showed non-inferiority to higher accumulated dose regimens regarding re-exacerbation risk in patients with AECOPD. However, it remains unclear whether 14-day or 2-5-day regimens would result in shorter admission durations and changes in mortality risk. We explored this by analysing the number of days alive and out of hospital based on two randomised controlled trials with different corticosteroid regimens. Methods We pooled individual patient data from the two available multicentre randomised trials on corticosteroid-sparing regimens for AECOPD: the REDUCE (n = 314) and CORTICO-COP (n = 318) trials. In the 14-day regimen group, patients were older, fewer patients received pre-treatment with antibiotics and more patients received pre-treatment with systemic corticosteroids. Patients randomly allocated to the 14-day and 2-5-day regimens were compared, with adjustment for baseline differences. Results The number of days alive and out of hospital within 14 days from recruitment was higher for the 2-5 day regimen group (mean 8.4 days; 95% confidence interval [CI] 8.0-8.8) than the 14-day regimen patient group (4.2 days; 95% CI3.4-4.9; p < 0.001). The 14-day AECOPD group had longer hospital stays (mean difference, 5.4 days [standard error +/- 0.6]; p < 0.0001) and decreased likelihood of discharge within 30 days (hazard ratio [HR] 0.5; 95% CI 0.4-0.6; p < 0.0001). Comparing the 14-day regimen and the 2-5 day regimen group showed no differences in the composite endpoint 'death or ICU admission' (odds ratio [OR] 1.4; 95% CI 0.8-2.3; p = 0.15), new or aggravated hypertension (OR 1.5; 95% CI 0.9-2.7; p = 0.15), or mortality risk (HR 0.8; 95% CI 0.4-1.5; p = 0.45) during the 6-month follow-up period. Conclusion 14-day corticosteroid regimens were associated with longer hospital stays and fewer days alive and out of hospital within 14 days, with no apparent 6-month benefit regarding death or admission to ICU in COPD patients. Our results favour 2-5 day regimens for treating COPD exacerbations. However, prospective studies are needed to validate these findings.