Effectiveness of daily versus non‐daily granulocyte colony‐stimulating factors in patients with solid tumours undergoing chemotherapy: a multivariate analysis of data from current practice We conducted a multicentre, retrospective, observational study including patients with solid tumours (excluding breast cancer) that received granulocyte colony‐stimulating factors (G‐CSF) and chemotherapy. We investigated the effectiveness of daily vs. non‐daily G‐CSFs (pegfilgrastim) adjusting by potential confounders. The study included 391 patients (211 daily G‐CSF; 180 pegfilgrastim), from whom 47.3% received primary prophylaxis (PP) (57.8% pegfilgrastim), 26.3% secondary prophylaxis (SP: initiation after cycle 1 and no reactive treatment in any cycle) (51.5% pegfilgrastim) and 26.3% reactive treatment (19.4% pegfilgrastim). Only 42.2% of patients with daily G‐CSF and 46.2% with pegfilgrastim initiated prophylaxis within 72 h after chemotherapy, and only 10.5% of patients with daily G‐CSF received it for ≥7 days. In the multivariate models, daily G‐CSF was associated with higher risk of grade 3‐4 neutropenia (G3‐4N) vs. pegfilgrastim odds ratio (OR): 1.73, 95% confidence interval (CI): 1.004–2.97. Relative to SP, PP protected against G3‐4N (OR for SP vs. PP: 6.0, 95%CI: 3.2–11.4) and febrile neutropenia (OR: 3.1, 95%CI: 1.1–8.8), and was associated to less chemotherapy dose delays and reductions (OR for relative dose intensity <85% for SP vs. PP: 3.1, 95%CI: 1.7–5.4) and higher response rate (OR: 2.1, 95%CI: 1.2–3.7). Data suggest that pegfilgrastim, compared with a daily G‐CSF, and PP, compared with SP, could be more effective in preventing neutropenia and its related events in the clinical practice.