Laboratory Changes Following Helicobacter pylori Treatment-Compatible Prescribing: A Retrospective Paired Cohort Study

Background and Objectives: Helicobacter pylori infection is associated with iron-deficiency anaemia, but haemoglobin response after treatment is heterogeneous and often overlaps with iron therapy. We estimated within-patient laboratory change after treatment-compatible prescribing in routine care. Materials and Methods: This single-centre retrospective paired cohort study compared the last haemoglobin value during days −180 to −1 with the value closest to day +90 within days +30 to +180. Mean paired change and 95% confidence interval (CI) were estimated in 258 patients. Timing and other sensitivity analyses, five secondary outcomes with Benjamini–Hochberg adjustment, and post hoc recorded-iron groups were evaluated. Prescribing records did not confirm ingestion, adherence, completion, or eradication. Results: Mean haemoglobin increased by 2.76 g/L (95% CI 1.29 to 4.23; p = 0.000273). Post hoc mean changes were 0.02 g/L without recorded iron, 8.07 g/L with iron recorded during days −90 to −1, and 12.89 g/L with iron recorded after index but not during those days. Mean corpuscular volume was the only secondary outcome significant after adjustment; no exploratory outcome remained significant after correction. Conclusions: Haemoglobin increased after treatment-compatible prescribing, concentrated in post hoc recorded-iron groups; given incomplete follow-up and no untreated comparator, this quantifies post-prescribing change, not the effect of treatment or eradication.