Use of acid-suppressive therapy before anti-reflux surgery in 2922 patients: a nationwide register-based study in Denmark A. Lødrup* ,† , A. Potteg  ard ‡ , J. Hallas ‡,§ & P. Bytzer* ,¶ *Department of Medicine, Køge University Hospital, Køge, Denmark. † Diagnostic Center, Silkeborg Hospital, Silkeborg, Denmark. ‡ Clinical Pharmacology, Department of Public Health, University of Southern Denmark, Odense, Denmark. § Department of Clinical Chemistry & Pharmacology, Odense University Hospital, Odense, Denmark. ¶ Department of Clinical Medicine, Copenhagen University, Copenhagen, Denmark. Correspondence to: Dr A. Lødrup, Diagnostic Center, Silkeborg Hospital, Falkevej 3, Silkeborg DK-8600, Denmark. E-mail: loedrup.ab@gmail.com Publication data Submitted 12 March 2015 First decision 24 March 2015 Resubmitted 9 April 2015 Resubmitted 16 April 2015 Accepted 16 April 2015 This article was accepted for publication after full peer-review. SUMMARY Background Guidelines recommend that patients with gastro-oesophageal reflux disease are adequately treated with acid-suppressive therapy before undergoing anti-reflux surgery. Little is known of the use of acid-suppressive drugs before anti-reflux surgery. Aim This study aimed to determine the use of proton pump inhibitors and H 2 - receptor antagonists in the year before anti-reflux surgery. Methods A nationwide retrospective study of all patients aged ≥18 undergoing first- time anti-reflux surgery in Denmark during 2000–2012 using data from three different sources: the Danish National Register of Patients, the Danish National Prescription Register, and the Danish Person Register. Results The study population thus included 2922 patients (median age: 48 years, 55.7% male). The annual proportion of patients redeeming ≥180 DDD of acid-suppressive therapy increased from 17.0% 5 years before anti-reflux surgery to 64.9% 1 year before. The probability for inadequate dosing 1 year before surgery (<180 DDD) was significantly increased for younger patients, patients operated in the period 2000–2003, patients who had not undergone pre-surgical manometry, pH- or impedance monitoring, and patients who had not redeemed prescriptions on NSAID or anti-platelet drugs. Conclusion Compliance with medical therapy should be evaluated thoroughly before planning anti-reflux surgery, as a high proportion of patients receive inade- quate dosing of acid-suppressive therapy prior to the operation. Aliment Pharmacol Ther ª 2015 John Wiley & Sons Ltd 1 doi:10.1111/apt.13230 Alimentary Pharmacology and Therapeutics